citus/src/backend/distributed/commands/multi_copy.c

3997 lines
115 KiB
C

/*-------------------------------------------------------------------------
*
* multi_copy.c
* This file contains implementation of COPY utility for distributed
* tables.
*
* The CitusCopyFrom function should be called from the utility hook to process
* COPY ... FROM commands on distributed tables. CitusCopyFrom parses the input
* from stdin, a program, or a file, and decides to copy new rows to existing
* shards or new shards based on the partition method of the distributed table.
*
* If this is the first command in the transaction, we open a new connection for
* every shard placement. Otherwise we open as many connections as we can to
* not conflict with previous commands in transactions, in which case some shards
* may share connections. See the comments of CopyConnectionState for how we
* operate in that case.
*
* We use the PQputCopyData function to copy the data. Because PQputCopyData
* transmits data asynchronously, the workers will ingest data at least partially
* in parallel.
*
* For hash-partitioned tables, if it fails to connect to a worker, the master
* rollbacks the distributed transaction, similar to the way DML statements
* are handled. If a failure occurs after connecting, the transaction
* is rolled back on all the workers. Note that,
* in the case of append-partitioned tables, if a fail occurs, immediately
* metadata changes are rolled back on the master node, but shard placements
* are left on the worker nodes.
*
* By default, COPY uses normal transactions on the workers. In the case of
* hash or range-partitioned tables, this can cause a problem when some of the
* transactions fail to commit while others have succeeded. To ensure no data
* is lost, COPY uses two-phase commit.
*
* Parsing options are processed and enforced on the node where copy command
* is run, while constraints are enforced on the worker. In either case,
* failure causes the whole COPY to roll back.
*
* Copyright (c) Citus Data, Inc.
*
* With contributions from Postgres Professional.
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "libpq-fe.h"
#include "miscadmin.h"
#include "pgstat.h"
#include <arpa/inet.h> /* for htons */
#include <netinet/in.h> /* for htons */
#include <string.h>
#include "distributed/pg_version_constants.h"
#include "access/htup_details.h"
#include "access/htup.h"
#include "access/sdir.h"
#include "access/sysattr.h"
#include "access/xact.h"
#include "catalog/namespace.h"
#include "catalog/pg_attribute.h"
#include "catalog/pg_type.h"
#include "commands/copy.h"
#include "commands/defrem.h"
#include "commands/progress.h"
#include "distributed/citus_safe_lib.h"
#include "distributed/commands/multi_copy.h"
#include "distributed/commands/utility_hook.h"
#include "distributed/intermediate_results.h"
#include "distributed/listutils.h"
#include "distributed/local_executor.h"
#include "distributed/log_utils.h"
#include "distributed/coordinator_protocol.h"
#include "distributed/metadata_cache.h"
#include "distributed/multi_executor.h"
#include "distributed/multi_partitioning_utils.h"
#include "distributed/multi_physical_planner.h"
#include "distributed/multi_router_planner.h"
#include "distributed/multi_executor.h"
#include "distributed/listutils.h"
#include "distributed/locally_reserved_shared_connections.h"
#include "distributed/placement_connection.h"
#include "distributed/relation_access_tracking.h"
#include "distributed/remote_commands.h"
#include "distributed/remote_transaction.h"
#include "distributed/replication_origin_session_utils.h"
#include "distributed/resource_lock.h"
#include "distributed/shard_pruning.h"
#include "distributed/shared_connection_stats.h"
#include "distributed/version_compat.h"
#include "distributed/worker_protocol.h"
#include "distributed/local_multi_copy.h"
#include "distributed/hash_helpers.h"
#include "distributed/transmit.h"
#include "executor/executor.h"
#include "foreign/foreign.h"
#include "libpq/libpq.h"
#include "libpq/pqformat.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "parser/parse_func.h"
#include "parser/parse_type.h"
#include "tcop/cmdtag.h"
#include "tsearch/ts_locale.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/syscache.h"
#include "utils/memutils.h"
/* constant used in binary protocol */
static const char BinarySignature[11] = "PGCOPY\n\377\r\n\0";
/* if true, skip validation of JSONB columns during COPY */
bool SkipJsonbValidationInCopy = true;
/* custom Citus option for appending to a shard */
#define APPEND_TO_SHARD_OPTION "append_to_shard"
/*
* Data size threshold to switch over the active placement for a connection.
* If this is too low, overhead of starting COPY commands will hurt the
* performance. If this is too high, buffered data will use lots of memory.
* 4MB is a good balance between memory usage and performance. Note that this
* is irrelevant in the common case where we open one connection per placement.
*/
int CopySwitchOverThresholdBytes = 4 * 1024 * 1024;
#define FILE_IS_OPEN(x) (x > -1)
typedef struct CopyShardState CopyShardState;
typedef struct CopyPlacementState CopyPlacementState;
/*
* Multiple shard placements can share one connection. Each connection has one
* of those placements as the activePlacementState, and others in the
* bufferedPlacementList. When we want to send a tuple to a CopyPlacementState,
* we check if it is the active one in its connectionState, and in this case we
* directly put data on wire. Otherwise, we buffer it so we can put it on wire
* later, when copy ends or a switch-over happens. See CitusSendTupleToPlacements()
* for more details.
*
* This is done so we are compatible with adaptive_executor. If a previous command
* in the current transaction has been executed using adaptive_executor.c, then
* CopyGetPlacementConnection() might return the same connection for multiple
* placements. We support that case by the buffering mechanism described above.
*
* If no previous command in the current transaction has used adaptive_executor.c,
* then CopyGetPlacementConnection() returns one connection per placement and no
* buffering happens and we put the copy data directly on connection.
*/
typedef struct CopyConnectionState
{
/* Used as hash key. Equal to PQsocket(connection->pgConn). */
int socket;
MultiConnection *connection;
/*
* Placement for which we have an active COPY going on over connection.
* Can be NULL.
*/
CopyPlacementState *activePlacementState;
/*
* Other placements that we are buffering data for. Later when a switch-over
* happens, we remove an item from this list and set it to activePlacementState.
* In this case, old activePlacementState isn't NULL, is added to this list.
*/
dlist_head bufferedPlacementList;
/* length of bufferedPlacementList, to avoid iterations over the list when needed */
int bufferedPlacementCount;
} CopyConnectionState;
struct CopyPlacementState
{
/* Connection state to which the placemement is assigned to. */
CopyConnectionState *connectionState;
/* State of shard to which the placement belongs to. */
CopyShardState *shardState;
/* node group ID of the placement */
int32 groupId;
/*
* Buffered COPY data. When the placement is activePlacementState of
* some connection, this is empty. Because in that case we directly
* send the data over connection.
*/
StringInfo data;
/* List node for CopyConnectionState->bufferedPlacementList. */
dlist_node bufferedPlacementNode;
};
struct CopyShardState
{
/* Used as hash key. */
uint64 shardId;
/* used for doing local copy, either for a shard or a co-located file */
CopyOutState copyOutState;
/* used when copy is targeting co-located file */
FileCompat fileDest;
/* containsLocalPlacement is true if we have a local placement for the shard id of this state */
bool containsLocalPlacement;
/* List of CopyPlacementStates for all active placements of the shard. */
List *placementStateList;
};
/*
* Represents the state for allowing copy via local
* execution.
*/
typedef enum LocalCopyStatus
{
LOCAL_COPY_REQUIRED,
LOCAL_COPY_OPTIONAL,
LOCAL_COPY_DISABLED
} LocalCopyStatus;
/* Local functions forward declarations */
static void CopyToExistingShards(CopyStmt *copyStatement,
QueryCompletion *completionTag);
static bool IsCopyInBinaryFormat(CopyStmt *copyStatement);
static List * FindJsonbInputColumns(TupleDesc tupleDescriptor,
List *inputColumnNameList);
static List * RemoveOptionFromList(List *optionList, char *optionName);
static bool BinaryOutputFunctionDefined(Oid typeId);
static bool BinaryInputFunctionDefined(Oid typeId);
static void SendCopyBinaryHeaders(CopyOutState copyOutState, int64 shardId,
List *connectionList);
static void SendCopyBinaryFooters(CopyOutState copyOutState, int64 shardId,
List *connectionList);
static StringInfo ConstructCopyStatement(CopyStmt *copyStatement, int64 shardId);
static void SendCopyDataToAll(StringInfo dataBuffer, int64 shardId, List *connectionList);
static void SendCopyDataToPlacement(StringInfo dataBuffer, int64 shardId,
MultiConnection *connection);
static uint32 AvailableColumnCount(TupleDesc tupleDescriptor);
static Oid TypeForColumnName(Oid relationId, TupleDesc tupleDescriptor, char *columnName);
static Oid * TypeArrayFromTupleDescriptor(TupleDesc tupleDescriptor);
static CopyCoercionData * ColumnCoercionPaths(TupleDesc destTupleDescriptor,
TupleDesc inputTupleDescriptor,
Oid destRelId, List *columnNameList,
Oid *finalColumnTypeArray);
static FmgrInfo * TypeOutputFunctions(uint32 columnCount, Oid *typeIdArray,
bool binaryFormat);
#if PG_VERSION_NUM < PG_VERSION_14
static List * CopyGetAttnums(TupleDesc tupDesc, Relation rel, List *attnamelist);
#endif
static bool CopyStatementHasFormat(CopyStmt *copyStatement, char *formatName);
static void CitusCopyFrom(CopyStmt *copyStatement, QueryCompletion *completionTag);
static void EnsureCopyCanRunOnRelation(Oid relationId);
static HTAB * CreateConnectionStateHash(MemoryContext memoryContext);
static HTAB * CreateShardStateHash(MemoryContext memoryContext);
static CopyConnectionState * GetConnectionState(HTAB *connectionStateHash,
MultiConnection *connection);
static CopyShardState * GetShardState(uint64 shardId, HTAB *shardStateHash,
HTAB *connectionStateHash,
bool *found, bool shouldUseLocalCopy, CopyOutState
copyOutState, bool isColocatedIntermediateResult,
bool isPublishable);
static MultiConnection * CopyGetPlacementConnection(HTAB *connectionStateHash,
ShardPlacement *placement,
bool colocatedIntermediateResult);
static bool HasReachedAdaptiveExecutorPoolSize(List *connectionStateHash);
static MultiConnection * GetLeastUtilisedCopyConnection(List *connectionStateList,
char *nodeName, int nodePort);
static List * ConnectionStateList(HTAB *connectionStateHash);
static List * ConnectionStateListToNode(HTAB *connectionStateHash,
const char *hostname, int32 port);
static void InitializeCopyShardState(CopyShardState *shardState,
HTAB *connectionStateHash,
uint64 shardId,
bool canUseLocalCopy,
CopyOutState copyOutState,
bool colocatedIntermediateResult, bool
isPublishable);
static void StartPlacementStateCopyCommand(CopyPlacementState *placementState,
CopyStmt *copyStatement,
CopyOutState copyOutState);
static void EndPlacementStateCopyCommand(CopyPlacementState *placementState,
CopyOutState copyOutState);
static void UnclaimCopyConnections(List *connectionStateList);
static void ShutdownCopyConnectionState(CopyConnectionState *connectionState,
CitusCopyDestReceiver *copyDest);
static SelectStmt * CitusCopySelect(CopyStmt *copyStatement);
static void CitusCopyTo(CopyStmt *copyStatement, QueryCompletion *completionTag);
static int64 ForwardCopyDataFromConnection(CopyOutState copyOutState,
MultiConnection *connection);
/* Private functions copied and adapted from copy.c in PostgreSQL */
static void SendCopyBegin(CopyOutState cstate);
static void SendCopyEnd(CopyOutState cstate);
static void CopySendData(CopyOutState outputState, const void *databuf, int datasize);
static void CopySendString(CopyOutState outputState, const char *str);
static void CopySendChar(CopyOutState outputState, char c);
static void CopySendInt32(CopyOutState outputState, int32 val);
static void CopySendInt16(CopyOutState outputState, int16 val);
static void CopySendEndOfRow(CopyOutState cstate, bool includeEndOfLine);
static void CopyAttributeOutText(CopyOutState outputState, char *string);
static inline void CopyFlushOutput(CopyOutState outputState, char *start, char *pointer);
static bool CitusSendTupleToPlacements(TupleTableSlot *slot,
CitusCopyDestReceiver *copyDest);
static void AddPlacementStateToCopyConnectionStateBuffer(CopyConnectionState *
connectionState,
CopyPlacementState *
placementState);
static void RemovePlacementStateFromCopyConnectionStateBuffer(CopyConnectionState *
connectionState,
CopyPlacementState *
placementState);
static uint64 ProcessAppendToShardOption(Oid relationId, CopyStmt *copyStatement);
static uint64 ShardIdForTuple(CitusCopyDestReceiver *copyDest, Datum *columnValues,
bool *columnNulls);
/* CitusCopyDestReceiver functions */
static void CitusCopyDestReceiverStartup(DestReceiver *copyDest, int operation,
TupleDesc inputTupleDesc);
static bool CitusCopyDestReceiverReceive(TupleTableSlot *slot,
DestReceiver *copyDest);
static void CitusCopyDestReceiverShutdown(DestReceiver *destReceiver);
static void CitusCopyDestReceiverDestroy(DestReceiver *destReceiver);
static bool ContainsLocalPlacement(int64 shardId);
static void CompleteCopyQueryTagCompat(QueryCompletion *completionTag, uint64
processedRowCount);
static void FinishLocalCopy(CitusCopyDestReceiver *copyDest);
static void CreateLocalColocatedIntermediateFile(CitusCopyDestReceiver *copyDest,
CopyShardState *shardState);
static void FinishLocalColocatedIntermediateFiles(CitusCopyDestReceiver *copyDest);
static void CloneCopyOutStateForLocalCopy(CopyOutState from, CopyOutState to);
static LocalCopyStatus GetLocalCopyStatus(void);
static bool ShardIntervalListHasLocalPlacements(List *shardIntervalList);
static void LogLocalCopyToRelationExecution(uint64 shardId);
static void LogLocalCopyToFileExecution(uint64 shardId);
/* exports for SQL callable functions */
PG_FUNCTION_INFO_V1(citus_text_send_as_jsonb);
/*
* CitusCopyFrom implements the COPY table_name FROM. It dispacthes the copy
* statement to related subfunctions based on where the copy command is run
* and the partition method of the distributed table.
*/
static void
CitusCopyFrom(CopyStmt *copyStatement, QueryCompletion *completionTag)
{
UseCoordinatedTransaction();
/* disallow COPY to/from file or program except for superusers */
if (copyStatement->filename != NULL && !superuser())
{
if (copyStatement->is_program)
{
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to COPY to or from an external program"),
errhint("Anyone can COPY to stdout or from stdin. "
"psql's \\copy command also works for anyone.")));
}
else
{
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to COPY to or from a file"),
errhint("Anyone can COPY to stdout or from stdin. "
"psql's \\copy command also works for anyone.")));
}
}
Oid relationId = RangeVarGetRelid(copyStatement->relation, NoLock, false);
EnsureCopyCanRunOnRelation(relationId);
CitusTableCacheEntry *cacheEntry = GetCitusTableCacheEntry(relationId);
/* disallow modifications to a partition table which have rep. factor > 1 */
EnsurePartitionTableNotReplicated(relationId);
if (IsCitusTableTypeCacheEntry(cacheEntry, HASH_DISTRIBUTED) ||
IsCitusTableTypeCacheEntry(cacheEntry, RANGE_DISTRIBUTED) ||
IsCitusTableTypeCacheEntry(cacheEntry, APPEND_DISTRIBUTED) ||
!HasDistributionKeyCacheEntry(cacheEntry))
{
CopyToExistingShards(copyStatement, completionTag);
}
else
{
ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("unsupported partition method")));
}
XactModificationLevel = XACT_MODIFICATION_DATA;
}
/*
* EnsureCopyCanRunOnRelation throws error is the database in read-only mode.
*/
static void
EnsureCopyCanRunOnRelation(Oid relationId)
{
/* first, do the regular check and give consistent errors with regular queries */
EnsureModificationsCanRunOnRelation(relationId);
/*
* We use 2PC for all COPY commands. It means that we cannot allow any COPY
* on replicas even if the user allows via WritableStandbyCoordinator GUC.
*/
if (RecoveryInProgress() && WritableStandbyCoordinator)
{
ereport(ERROR, (errmsg("COPY command to Citus tables is not allowed in "
"read-only mode"),
errhint("All COPY commands to citus tables happen via 2PC, "
"and 2PC requires the database to be in a writable state."),
errdetail("the database is read-only")));
}
}
/*
* CopyToExistingShards implements the COPY table_name FROM ... for hash or
* range-partitioned tables where there are already shards into which to copy
* rows.
*/
static void
CopyToExistingShards(CopyStmt *copyStatement, QueryCompletion *completionTag)
{
Oid tableId = RangeVarGetRelid(copyStatement->relation, NoLock, false);
List *columnNameList = NIL;
int partitionColumnIndex = INVALID_PARTITION_COLUMN_INDEX;
bool isInputFormatBinary = IsCopyInBinaryFormat(copyStatement);
uint64 processedRowCount = 0;
ErrorContextCallback errorCallback;
/* allocate column values and nulls arrays */
Relation distributedRelation = table_open(tableId, RowExclusiveLock);
TupleDesc tupleDescriptor = RelationGetDescr(distributedRelation);
uint32 columnCount = tupleDescriptor->natts;
Datum *columnValues = palloc0(columnCount * sizeof(Datum));
bool *columnNulls = palloc0(columnCount * sizeof(bool));
/* set up a virtual tuple table slot */
TupleTableSlot *tupleTableSlot = MakeSingleTupleTableSlot(tupleDescriptor,
&TTSOpsVirtual);
tupleTableSlot->tts_nvalid = columnCount;
tupleTableSlot->tts_values = columnValues;
tupleTableSlot->tts_isnull = columnNulls;
/* determine the partition column index in the tuple descriptor */
Var *partitionColumn = PartitionColumn(tableId, 0);
if (partitionColumn != NULL)
{
partitionColumnIndex = partitionColumn->varattno - 1;
}
/* build the list of column names for remote COPY statements */
for (int columnIndex = 0; columnIndex < columnCount; columnIndex++)
{
Form_pg_attribute currentColumn = TupleDescAttr(tupleDescriptor, columnIndex);
char *columnName = NameStr(currentColumn->attname);
if (currentColumn->attisdropped ||
currentColumn->attgenerated == ATTRIBUTE_GENERATED_STORED
)
{
continue;
}
columnNameList = lappend(columnNameList, columnName);
}
EState *executorState = CreateExecutorState();
MemoryContext executorTupleContext = GetPerTupleMemoryContext(executorState);
ExprContext *executorExpressionContext = GetPerTupleExprContext(executorState);
/* set up the destination for the COPY */
const bool publishableData = true;
CitusCopyDestReceiver *copyDest = CreateCitusCopyDestReceiver(tableId, columnNameList,
partitionColumnIndex,
executorState, NULL,
publishableData);
/* if the user specified an explicit append-to_shard option, write to it */
uint64 appendShardId = ProcessAppendToShardOption(tableId, copyStatement);
if (appendShardId != INVALID_SHARD_ID)
{
copyDest->appendShardId = appendShardId;
}
DestReceiver *dest = (DestReceiver *) copyDest;
dest->rStartup(dest, 0, tupleDescriptor);
/*
* Below, we change a few fields in the Relation to control the behaviour
* of BeginCopyFrom. However, we obviously should not do this in relcache
* and therefore make a copy of the Relation.
*/
Relation copiedDistributedRelation = (Relation) palloc(sizeof(RelationData));
Form_pg_class copiedDistributedRelationTuple =
(Form_pg_class) palloc(CLASS_TUPLE_SIZE);
/*
* There is no need to deep copy everything. We will just deep copy of the fields
* we will change.
*/
*copiedDistributedRelation = *distributedRelation;
*copiedDistributedRelationTuple = *distributedRelation->rd_rel;
copiedDistributedRelation->rd_rel = copiedDistributedRelationTuple;
copiedDistributedRelation->rd_att = CreateTupleDescCopyConstr(tupleDescriptor);
/*
* BeginCopyFrom opens all partitions of given partitioned table with relation_open
* and it expects its caller to close those relations. We do not have direct access
* to opened relations, thus we are changing relkind of partitioned tables so that
* Postgres will treat those tables as regular relations and will not open its
* partitions.
*/
if (PartitionedTable(tableId))
{
copiedDistributedRelationTuple->relkind = RELKIND_RELATION;
}
/*
* We make an optimisation to skip JSON parsing for JSONB columns, because many
* Citus users have large objects in this column and parsing it on the coordinator
* causes significant CPU overhead. We do this by forcing BeginCopyFrom and
* NextCopyFrom to parse the column as text and then encoding it as JSON again
* by using citus_text_send_as_jsonb as the binary output function.
*
* The main downside of enabling this optimisation is that it defers validation
* until the object is parsed by the worker, which is unable to give an accurate
* line number.
*/
if (SkipJsonbValidationInCopy && !isInputFormatBinary)
{
CopyOutState copyOutState = copyDest->copyOutState;
ListCell *jsonbColumnIndexCell = NULL;
/* get the column indices for all JSONB columns that appear in the input */
List *jsonbColumnIndexList = FindJsonbInputColumns(
copiedDistributedRelation->rd_att,
copyStatement->attlist);
foreach(jsonbColumnIndexCell, jsonbColumnIndexList)
{
int jsonbColumnIndex = lfirst_int(jsonbColumnIndexCell);
Form_pg_attribute currentColumn =
TupleDescAttr(copiedDistributedRelation->rd_att, jsonbColumnIndex);
if (jsonbColumnIndex == partitionColumnIndex)
{
/*
* In the curious case of using a JSONB column as partition column,
* we leave it as is because we want to make sure the hashing works
* correctly.
*/
continue;
}
ereport(DEBUG1, (errmsg("parsing JSONB column %s as text",
NameStr(currentColumn->attname))));
/* parse the column as text instead of JSONB */
currentColumn->atttypid = TEXTOID;
if (copyOutState->binary)
{
Oid textSendAsJsonbFunctionId = CitusTextSendAsJsonbFunctionId();
/*
* If we're using binary encoding between coordinator and workers
* then we should honour the format expected by jsonb_recv, which
* is a version number followed by text. We therefore use an output
* function which sends the text as if it were jsonb, namely by
* prepending a version number.
*/
fmgr_info(textSendAsJsonbFunctionId,
&copyDest->columnOutputFunctions[jsonbColumnIndex]);
}
else
{
Oid textoutFunctionId = TextOutFunctionId();
fmgr_info(textoutFunctionId,
&copyDest->columnOutputFunctions[jsonbColumnIndex]);
}
}
}
/* initialize copy state to read from COPY data source */
CopyFromState copyState = BeginCopyFrom_compat(NULL,
copiedDistributedRelation,
NULL,
copyStatement->filename,
copyStatement->is_program,
NULL,
copyStatement->attlist,
copyStatement->options);
/* set up callback to identify error line number */
errorCallback.callback = CopyFromErrorCallback;
errorCallback.arg = (void *) copyState;
errorCallback.previous = error_context_stack;
error_context_stack = &errorCallback;
while (true)
{
ResetPerTupleExprContext(executorState);
MemoryContext oldContext = MemoryContextSwitchTo(executorTupleContext);
/* parse a row from the input */
bool nextRowFound = NextCopyFrom(copyState, executorExpressionContext,
columnValues, columnNulls);
if (!nextRowFound)
{
MemoryContextSwitchTo(oldContext);
break;
}
CHECK_FOR_INTERRUPTS();
MemoryContextSwitchTo(oldContext);
dest->receiveSlot(tupleTableSlot, dest);
++processedRowCount;
#if PG_VERSION_NUM >= PG_VERSION_14
pgstat_progress_update_param(PROGRESS_COPY_TUPLES_PROCESSED, processedRowCount);
#endif
}
EndCopyFrom(copyState);
/* all lines have been copied, stop showing line number in errors */
error_context_stack = errorCallback.previous;
/* finish the COPY commands */
dest->rShutdown(dest);
dest->rDestroy(dest);
ExecDropSingleTupleTableSlot(tupleTableSlot);
FreeExecutorState(executorState);
table_close(distributedRelation, NoLock);
CHECK_FOR_INTERRUPTS();
if (completionTag != NULL)
{
CompleteCopyQueryTagCompat(completionTag, processedRowCount);
}
}
/*
* IsCopyInBinaryFormat determines whether the given COPY statement has the
* WITH (format binary) option.
*/
static bool
IsCopyInBinaryFormat(CopyStmt *copyStatement)
{
ListCell *optionCell = NULL;
foreach(optionCell, copyStatement->options)
{
DefElem *defel = lfirst_node(DefElem, optionCell);
if (strcmp(defel->defname, "format") == 0 &&
strcmp(defGetString(defel), "binary") == 0)
{
return true;
}
}
return false;
}
/*
* FindJsonbInputColumns finds columns in the tuple descriptor that have
* the JSONB type and appear in inputColumnNameList. If the list is empty then
* all JSONB columns are returned.
*/
static List *
FindJsonbInputColumns(TupleDesc tupleDescriptor, List *inputColumnNameList)
{
List *jsonbColumnIndexList = NIL;
int columnCount = tupleDescriptor->natts;
for (int columnIndex = 0; columnIndex < columnCount; columnIndex++)
{
Form_pg_attribute currentColumn = TupleDescAttr(tupleDescriptor, columnIndex);
if (currentColumn->attisdropped)
{
continue;
}
if (currentColumn->atttypid != JSONBOID)
{
continue;
}
if (inputColumnNameList != NIL)
{
ListCell *inputColumnCell = NULL;
bool isInputColumn = false;
foreach(inputColumnCell, inputColumnNameList)
{
char *inputColumnName = strVal(lfirst(inputColumnCell));
if (namestrcmp(&currentColumn->attname, inputColumnName) == 0)
{
isInputColumn = true;
break;
}
}
if (!isInputColumn)
{
continue;
}
}
jsonbColumnIndexList = lappend_int(jsonbColumnIndexList, columnIndex);
}
return jsonbColumnIndexList;
}
static void
CompleteCopyQueryTagCompat(QueryCompletion *completionTag, uint64 processedRowCount)
{
SetQueryCompletion(completionTag, CMDTAG_COPY, processedRowCount);
}
/*
* RemoveOptionFromList removes an option from a list of options in a
* COPY .. WITH (..) statement by name and returns the resulting list.
*/
static List *
RemoveOptionFromList(List *optionList, char *optionName)
{
ListCell *optionCell = NULL;
foreach(optionCell, optionList)
{
DefElem *option = (DefElem *) lfirst(optionCell);
if (strncmp(option->defname, optionName, NAMEDATALEN) == 0)
{
return list_delete_cell(optionList, optionCell);
}
}
return optionList;
}
/*
* CanUseBinaryCopyFormat iterates over columns of the relation and looks for a
* column whose type is array of user-defined type or composite type. If it finds
* such column, that means we cannot use binary format for COPY, because binary
* format sends Oid of the types, which are generally not same in master and
* worker nodes for user-defined types. If the function can not detect a binary
* output function for any of the column, it returns false.
*/
bool
CanUseBinaryCopyFormat(TupleDesc tupleDescription)
{
bool useBinaryCopyFormat = true;
int totalColumnCount = tupleDescription->natts;
for (int columnIndex = 0; columnIndex < totalColumnCount; columnIndex++)
{
Form_pg_attribute currentColumn = TupleDescAttr(tupleDescription, columnIndex);
if (currentColumn->attisdropped ||
currentColumn->attgenerated == ATTRIBUTE_GENERATED_STORED
)
{
continue;
}
Oid typeId = currentColumn->atttypid;
if (!CanUseBinaryCopyFormatForType(typeId))
{
useBinaryCopyFormat = false;
break;
}
}
return useBinaryCopyFormat;
}
/*
* CanUseBinaryCopyFormatForTargetList returns true if we can use binary
* copy format for all columns of the given target list.
*/
bool
CanUseBinaryCopyFormatForTargetList(List *targetEntryList)
{
ListCell *targetEntryCell = NULL;
foreach(targetEntryCell, targetEntryList)
{
TargetEntry *targetEntry = (TargetEntry *) lfirst(targetEntryCell);
Node *targetExpr = (Node *) targetEntry->expr;
Oid columnType = exprType(targetExpr);
if (!CanUseBinaryCopyFormatForType(columnType))
{
return false;
}
}
return true;
}
/*
* CanUseBinaryCopyFormatForType determines whether it is safe to use the
* binary copy format for the given type. See contents of the function for
* details of when it's safe to use binary copy.
*/
bool
CanUseBinaryCopyFormatForType(Oid typeId)
{
if (!BinaryOutputFunctionDefined(typeId))
{
return false;
}
if (!BinaryInputFunctionDefined(typeId))
{
return false;
}
/*
* A row type can contain any types, possibly types that don't have
* the binary input and output functions defined.
*/
if (type_is_rowtype(typeId))
{
/*
* TODO: Inspect the types inside the record and check if all of them
* can be binary encoded. If so, it's safe to use binary encoding.
*
* IMPORTANT: When implementing this todo keep the following in mind:
*
* In PG versions before PG14 the record_recv function would error out
* more than necessary.
*
* It errors out when any of the columns in the row have a type oid
* that doesn't match with the oid in the received data. This happens
* pretty much always for non built in types, because their oids differ
* between postgres intallations. So for those Postgres versions we
* would need a check like the following for each column:
*
* if (columnType >= FirstNormalObjectId) {
* return false
* }
*/
return false;
}
HeapTuple typeTup = typeidType(typeId);
Form_pg_type type = (Form_pg_type) GETSTRUCT(typeTup);
Oid elementType = type->typelem;
#if PG_VERSION_NUM < PG_VERSION_14
char typeCategory = type->typcategory;
#endif
ReleaseSysCache(typeTup);
#if PG_VERSION_NUM < PG_VERSION_14
/*
* In PG versions before PG14 the array_recv function would error out more
* than necessary.
*
* It errors out when the element type its oids don't match with the oid in
* the received data. This happens pretty much always for non built in
* types, because their oids differ between postgres intallations. So we
* skip binary encoding when the element type is a non built in type.
*/
if (typeCategory == TYPCATEGORY_ARRAY && elementType >= FirstNormalObjectId)
{
return false;
}
#endif
/*
* Any type that is a wrapper around an element type (e.g. arrays and
* ranges) require the element type to also has support for binary
* encoding.
*/
if (elementType != InvalidOid)
{
if (!CanUseBinaryCopyFormatForType(elementType))
{
return false;
}
}
/*
* For domains, make sure that the underlying type can be binary copied.
*/
Oid baseTypeId = getBaseType(typeId);
if (typeId != baseTypeId)
{
if (!CanUseBinaryCopyFormatForType(baseTypeId))
{
return false;
}
}
return true;
}
/*
* BinaryOutputFunctionDefined checks whether binary output function is defined
* for the given type.
*/
static bool
BinaryOutputFunctionDefined(Oid typeId)
{
Oid typeFunctionId = InvalidOid;
Oid typeIoParam = InvalidOid;
int16 typeLength = 0;
bool typeByVal = false;
char typeAlign = 0;
char typeDelim = 0;
get_type_io_data(typeId, IOFunc_send, &typeLength, &typeByVal,
&typeAlign, &typeDelim, &typeIoParam, &typeFunctionId);
return OidIsValid(typeFunctionId);
}
/*
* BinaryInputFunctionDefined checks whether binary output function is defined
* for the given type.
*/
static bool
BinaryInputFunctionDefined(Oid typeId)
{
Oid typeFunctionId = InvalidOid;
Oid typeIoParam = InvalidOid;
int16 typeLength = 0;
bool typeByVal = false;
char typeAlign = 0;
char typeDelim = 0;
get_type_io_data(typeId, IOFunc_receive, &typeLength, &typeByVal,
&typeAlign, &typeDelim, &typeIoParam, &typeFunctionId);
return OidIsValid(typeFunctionId);
}
/* Send copy binary headers to given connections */
static void
SendCopyBinaryHeaders(CopyOutState copyOutState, int64 shardId, List *connectionList)
{
resetStringInfo(copyOutState->fe_msgbuf);
AppendCopyBinaryHeaders(copyOutState);
SendCopyDataToAll(copyOutState->fe_msgbuf, shardId, connectionList);
}
/* Send copy binary footers to given connections */
static void
SendCopyBinaryFooters(CopyOutState copyOutState, int64 shardId, List *connectionList)
{
resetStringInfo(copyOutState->fe_msgbuf);
AppendCopyBinaryFooters(copyOutState);
SendCopyDataToAll(copyOutState->fe_msgbuf, shardId, connectionList);
}
/*
* ConstructCopyStatement constructs the text of a COPY statement for a particular
* shard.
*/
static StringInfo
ConstructCopyStatement(CopyStmt *copyStatement, int64 shardId)
{
StringInfo command = makeStringInfo();
char *schemaName = copyStatement->relation->schemaname;
char *relationName = copyStatement->relation->relname;
char *shardName = pstrdup(relationName);
AppendShardIdToName(&shardName, shardId);
char *shardQualifiedName = quote_qualified_identifier(schemaName, shardName);
appendStringInfo(command, "COPY %s ", shardQualifiedName);
if (copyStatement->attlist != NIL)
{
ListCell *columnNameCell = NULL;
bool appendedFirstName = false;
foreach(columnNameCell, copyStatement->attlist)
{
char *columnName = strVal(lfirst(columnNameCell));
const char *quotedColumnName = quote_identifier(columnName);
if (!appendedFirstName)
{
appendStringInfo(command, "(%s", quotedColumnName);
appendedFirstName = true;
}
else
{
appendStringInfo(command, ", %s", quotedColumnName);
}
}
appendStringInfoString(command, ") ");
}
if (copyStatement->is_from)
{
appendStringInfoString(command, "FROM STDIN");
}
else
{
appendStringInfoString(command, "TO STDOUT");
}
if (copyStatement->options != NIL)
{
ListCell *optionCell = NULL;
appendStringInfoString(command, " WITH (");
foreach(optionCell, copyStatement->options)
{
DefElem *defel = (DefElem *) lfirst(optionCell);
if (optionCell != list_head(copyStatement->options))
{
appendStringInfoString(command, ", ");
}
appendStringInfo(command, "%s", defel->defname);
if (defel->arg == NULL)
{
/* option without value */
}
else if (IsA(defel->arg, String))
{
char *value = defGetString(defel);
/* make sure strings are quoted (may contain reserved characters) */
appendStringInfo(command, " %s", quote_literal_cstr(value));
}
else if (IsA(defel->arg, List))
{
List *nameList = defGetStringList(defel);
appendStringInfo(command, " (%s)", NameListToQuotedString(nameList));
}
else
{
char *value = defGetString(defel);
/* numeric options or * should not have quotes */
appendStringInfo(command, " %s", value);
}
}
appendStringInfoString(command, ")");
}
return command;
}
/*
* SendCopyDataToAll sends copy data to all connections in a list.
*/
static void
SendCopyDataToAll(StringInfo dataBuffer, int64 shardId, List *connectionList)
{
ListCell *connectionCell = NULL;
foreach(connectionCell, connectionList)
{
MultiConnection *connection = (MultiConnection *) lfirst(connectionCell);
SendCopyDataToPlacement(dataBuffer, shardId, connection);
}
}
/*
* SendCopyDataToPlacement sends serialized COPY data to a specific shard placement
* over the given connection.
*/
static void
SendCopyDataToPlacement(StringInfo dataBuffer, int64 shardId, MultiConnection *connection)
{
if (!PutRemoteCopyData(connection, dataBuffer->data, dataBuffer->len))
{
ereport(ERROR, (errcode(ERRCODE_IO_ERROR),
errmsg("failed to COPY to shard " INT64_FORMAT " on %s:%d",
shardId, connection->hostname, connection->port),
errdetail("failed to send %d bytes %s", dataBuffer->len,
dataBuffer->data)));
}
}
/*
* EndRemoteCopy ends the COPY input on all connections, and unclaims connections.
* This reports an error on failure.
*/
void
EndRemoteCopy(int64 shardId, List *connectionList)
{
ListCell *connectionCell = NULL;
foreach(connectionCell, connectionList)
{
MultiConnection *connection = (MultiConnection *) lfirst(connectionCell);
bool raiseInterrupts = true;
/* end the COPY input */
if (!PutRemoteCopyEnd(connection, NULL))
{
ereport(ERROR, (errcode(ERRCODE_IO_ERROR),
errmsg("failed to COPY to shard " INT64_FORMAT " on %s:%d",
shardId, connection->hostname, connection->port)));
}
/* check whether there were any COPY errors */
PGresult *result = GetRemoteCommandResult(connection, raiseInterrupts);
if (PQresultStatus(result) != PGRES_COMMAND_OK)
{
ReportCopyError(connection, result);
}
PQclear(result);
ForgetResults(connection);
UnclaimConnection(connection);
}
}
/*
* ReportCopyError tries to report a useful error message for the user from
* the remote COPY error messages.
*/
void
ReportCopyError(MultiConnection *connection, PGresult *result)
{
char *remoteMessage = PQresultErrorField(result, PG_DIAG_MESSAGE_PRIMARY);
if (remoteMessage != NULL)
{
/* probably a constraint violation, show remote message and detail */
char *remoteDetail = PQresultErrorField(result, PG_DIAG_MESSAGE_DETAIL);
bool haveDetail = remoteDetail != NULL;
ereport(ERROR, (errmsg("%s", remoteMessage),
haveDetail ? errdetail("%s", remoteDetail) :
0));
}
else
{
/* trim the trailing characters */
remoteMessage = pchomp(PQerrorMessage(connection->pgConn));
ereport(ERROR, (errcode(ERRCODE_IO_ERROR),
errmsg("failed to complete COPY on %s:%d", connection->hostname,
connection->port),
errdetail("%s", remoteMessage)));
}
}
/*
* ConversionPathForTypes fills *result with all the data necessary for converting
* Datums of type inputType to Datums of type destType.
*/
void
ConversionPathForTypes(Oid inputType, Oid destType, CopyCoercionData *result)
{
Oid coercionFuncId = InvalidOid;
CoercionPathType coercionType = COERCION_PATH_RELABELTYPE;
if (destType == inputType)
{
result->coercionType = COERCION_PATH_RELABELTYPE;
return;
}
coercionType = find_coercion_pathway(destType, inputType,
COERCION_EXPLICIT,
&coercionFuncId);
switch (coercionType)
{
case COERCION_PATH_NONE:
{
ereport(ERROR, (errmsg("cannot cast %d to %d", inputType, destType)));
return;
}
case COERCION_PATH_ARRAYCOERCE:
{
Oid inputBaseType = get_base_element_type(inputType);
Oid destBaseType = get_base_element_type(destType);
CoercionPathType baseCoercionType = COERCION_PATH_NONE;
if (inputBaseType != InvalidOid && destBaseType != InvalidOid)
{
baseCoercionType = find_coercion_pathway(inputBaseType, destBaseType,
COERCION_EXPLICIT,
&coercionFuncId);
}
if (baseCoercionType != COERCION_PATH_COERCEVIAIO)
{
ereport(ERROR, (errmsg("can not run query which uses an implicit coercion"
" between array types")));
}
}
/* fallthrough */
case COERCION_PATH_COERCEVIAIO:
{
result->coercionType = COERCION_PATH_COERCEVIAIO;
{
bool typisvarlena = false; /* ignored */
Oid iofunc = InvalidOid;
getTypeOutputInfo(inputType, &iofunc, &typisvarlena);
fmgr_info(iofunc, &(result->outputFunction));
}
{
Oid iofunc = InvalidOid;
getTypeInputInfo(destType, &iofunc, &(result->typioparam));
fmgr_info(iofunc, &(result->inputFunction));
}
return;
}
case COERCION_PATH_FUNC:
{
result->coercionType = COERCION_PATH_FUNC;
fmgr_info(coercionFuncId, &(result->coerceFunction));
return;
}
case COERCION_PATH_RELABELTYPE:
{
result->coercionType = COERCION_PATH_RELABELTYPE;
return; /* the types are binary compatible, no need to call a function */
}
default:
Assert(false); /* there are no other options for this enum */
}
}
/*
* Returns the type of the provided column of the provided tuple. Throws an error if the
* column does not exist or is dropped.
*
* tupleDescriptor and relationId must refer to the same table.
*/
static Oid
TypeForColumnName(Oid relationId, TupleDesc tupleDescriptor, char *columnName)
{
AttrNumber destAttrNumber = get_attnum(relationId, columnName);
if (destAttrNumber == InvalidAttrNumber)
{
ereport(ERROR, (errmsg("invalid attr? %s", columnName)));
}
Form_pg_attribute attr = TupleDescAttr(tupleDescriptor, destAttrNumber - 1);
return attr->atttypid;
}
/*
* Walks a TupleDesc and returns an array of the types of each attribute.
* Returns InvalidOid in the place of dropped or generated attributes.
*/
static Oid *
TypeArrayFromTupleDescriptor(TupleDesc tupleDescriptor)
{
int columnCount = tupleDescriptor->natts;
Oid *typeArray = palloc0(columnCount * sizeof(Oid));
for (int columnIndex = 0; columnIndex < columnCount; columnIndex++)
{
Form_pg_attribute attr = TupleDescAttr(tupleDescriptor, columnIndex);
if (attr->attisdropped ||
attr->attgenerated == ATTRIBUTE_GENERATED_STORED
)
{
typeArray[columnIndex] = InvalidOid;
}
else
{
typeArray[columnIndex] = attr->atttypid;
}
}
return typeArray;
}
/*
* ColumnCoercionPaths scans the input and output tuples looking for mismatched types,
* it then returns an array of coercion functions to use on the input tuples, and an
* array of types which descript the output tuple
*/
static CopyCoercionData *
ColumnCoercionPaths(TupleDesc destTupleDescriptor, TupleDesc inputTupleDescriptor,
Oid destRelId, List *columnNameList,
Oid *finalColumnTypeArray)
{
int columnCount = inputTupleDescriptor->natts;
CopyCoercionData *coercePaths = palloc0(columnCount * sizeof(CopyCoercionData));
Oid *inputTupleTypes = TypeArrayFromTupleDescriptor(inputTupleDescriptor);
ListCell *currentColumnName = list_head(columnNameList);
for (int columnIndex = 0; columnIndex < columnCount; columnIndex++)
{
Oid inputTupleType = inputTupleTypes[columnIndex];
char *columnName = lfirst(currentColumnName);
if (inputTupleType == InvalidOid)
{
/* TypeArrayFromTupleDescriptor decided to skip this column */
continue;
}
Oid destTupleType = TypeForColumnName(destRelId, destTupleDescriptor, columnName);
finalColumnTypeArray[columnIndex] = destTupleType;
ConversionPathForTypes(inputTupleType, destTupleType,
&coercePaths[columnIndex]);
currentColumnName = lnext(columnNameList, currentColumnName);
if (currentColumnName == NULL)
{
/* the rest of inputTupleDescriptor are dropped columns, return early! */
break;
}
}
return coercePaths;
}
/*
* TypeOutputFunctions takes an array of types and returns an array of output functions
* for those types.
*/
static FmgrInfo *
TypeOutputFunctions(uint32 columnCount, Oid *typeIdArray, bool binaryFormat)
{
FmgrInfo *columnOutputFunctions = palloc0(columnCount * sizeof(FmgrInfo));
for (uint32 columnIndex = 0; columnIndex < columnCount; columnIndex++)
{
FmgrInfo *currentOutputFunction = &columnOutputFunctions[columnIndex];
Oid columnTypeId = typeIdArray[columnIndex];
bool typeVariableLength = false;
Oid outputFunctionId = InvalidOid;
if (columnTypeId == InvalidOid)
{
/* TypeArrayFromTupleDescriptor decided to skip this column */
continue;
}
else if (binaryFormat)
{
getTypeBinaryOutputInfo(columnTypeId, &outputFunctionId, &typeVariableLength);
}
else
{
getTypeOutputInfo(columnTypeId, &outputFunctionId, &typeVariableLength);
}
fmgr_info(outputFunctionId, currentOutputFunction);
}
return columnOutputFunctions;
}
/*
* ColumnOutputFunctions is a wrapper around TypeOutputFunctions, it takes a
* tupleDescriptor and returns an array of output functions, one for each column in
* the tuple.
*/
FmgrInfo *
ColumnOutputFunctions(TupleDesc rowDescriptor, bool binaryFormat)
{
uint32 columnCount = (uint32) rowDescriptor->natts;
Oid *columnTypes = TypeArrayFromTupleDescriptor(rowDescriptor);
FmgrInfo *outputFunctions =
TypeOutputFunctions(columnCount, columnTypes, binaryFormat);
return outputFunctions;
}
/*
* citus_text_send_as_jsonb sends a text as if it was a JSONB. This should only
* be used if the text is indeed valid JSON.
*/
Datum
citus_text_send_as_jsonb(PG_FUNCTION_ARGS)
{
text *inputText = PG_GETARG_TEXT_PP(0);
StringInfoData buf;
int version = 1;
pq_begintypsend(&buf);
pq_sendint(&buf, version, 1);
pq_sendtext(&buf, VARDATA_ANY(inputText), VARSIZE_ANY_EXHDR(inputText));
PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}
/*
* AppendCopyRowData serializes one row using the column output functions,
* and appends the data to the row output state object's message buffer.
* This function is modeled after the CopyOneRowTo() function in
* commands/copy.c, but only implements a subset of that functionality.
* Note that the caller of this function should reset row memory context
* to not bloat memory usage.
*/
void
AppendCopyRowData(Datum *valueArray, bool *isNullArray, TupleDesc rowDescriptor,
CopyOutState rowOutputState, FmgrInfo *columnOutputFunctions,
CopyCoercionData *columnCoercionPaths)
{
uint32 totalColumnCount = (uint32) rowDescriptor->natts;
uint32 availableColumnCount = AvailableColumnCount(rowDescriptor);
uint32 appendedColumnCount = 0;
MemoryContext oldContext = MemoryContextSwitchTo(rowOutputState->rowcontext);
if (rowOutputState->binary)
{
CopySendInt16(rowOutputState, availableColumnCount);
}
for (uint32 columnIndex = 0; columnIndex < totalColumnCount; columnIndex++)
{
Form_pg_attribute currentColumn = TupleDescAttr(rowDescriptor, columnIndex);
Datum value = valueArray[columnIndex];
bool isNull = isNullArray[columnIndex];
bool lastColumn = false;
if (!isNull && columnCoercionPaths != NULL)
{
value = CoerceColumnValue(value, &columnCoercionPaths[columnIndex]);
}
if (currentColumn->attisdropped ||
currentColumn->attgenerated == ATTRIBUTE_GENERATED_STORED
)
{
continue;
}
else if (rowOutputState->binary)
{
if (!isNull)
{
FmgrInfo *outputFunctionPointer = &columnOutputFunctions[columnIndex];
bytea *outputBytes = SendFunctionCall(outputFunctionPointer, value);
CopySendInt32(rowOutputState, VARSIZE(outputBytes) - VARHDRSZ);
CopySendData(rowOutputState, VARDATA(outputBytes),
VARSIZE(outputBytes) - VARHDRSZ);
}
else
{
CopySendInt32(rowOutputState, -1);
}
}
else
{
if (!isNull)
{
FmgrInfo *outputFunctionPointer = &columnOutputFunctions[columnIndex];
char *columnText = OutputFunctionCall(outputFunctionPointer, value);
CopyAttributeOutText(rowOutputState, columnText);
}
else
{
CopySendString(rowOutputState, rowOutputState->null_print_client);
}
lastColumn = ((appendedColumnCount + 1) == availableColumnCount);
if (!lastColumn)
{
CopySendChar(rowOutputState, rowOutputState->delim[0]);
}
}
appendedColumnCount++;
}
if (!rowOutputState->binary)
{
/* append default line termination string depending on the platform */
#ifndef WIN32
CopySendChar(rowOutputState, '\n');
#else
CopySendString(rowOutputState, "\r\n");
#endif
}
MemoryContextSwitchTo(oldContext);
}
/*
* CoerceColumnValue follows the instructions in *coercionPath and uses them to convert
* inputValue into a Datum of the correct type.
*/
Datum
CoerceColumnValue(Datum inputValue, CopyCoercionData *coercionPath)
{
switch (coercionPath->coercionType)
{
case 0:
{
return inputValue; /* this was a dropped column */
}
case COERCION_PATH_RELABELTYPE:
{
return inputValue; /* no need to do anything */
}
case COERCION_PATH_FUNC:
{
FmgrInfo *coerceFunction = &(coercionPath->coerceFunction);
Datum outputValue = FunctionCall1(coerceFunction, inputValue);
return outputValue;
}
case COERCION_PATH_COERCEVIAIO:
{
FmgrInfo *outFunction = &(coercionPath->outputFunction);
Datum textRepr = FunctionCall1(outFunction, inputValue);
FmgrInfo *inFunction = &(coercionPath->inputFunction);
Oid typioparam = coercionPath->typioparam;
Datum outputValue = FunctionCall3(inFunction, textRepr, typioparam,
Int32GetDatum(-1));
return outputValue;
}
default:
{
/* this should never happen */
ereport(ERROR, (errmsg("unsupported coercion type")));
}
}
}
/*
* AvailableColumnCount returns the number of columns in a tuple descriptor, excluding
* columns that were dropped.
*/
static uint32
AvailableColumnCount(TupleDesc tupleDescriptor)
{
uint32 columnCount = 0;
for (uint32 columnIndex = 0; columnIndex < tupleDescriptor->natts; columnIndex++)
{
Form_pg_attribute currentColumn = TupleDescAttr(tupleDescriptor, columnIndex);
if (!currentColumn->attisdropped &&
currentColumn->attgenerated != ATTRIBUTE_GENERATED_STORED
)
{
columnCount++;
}
}
return columnCount;
}
/*
* AppendCopyBinaryHeaders appends binary headers to the copy buffer in
* headerOutputState.
*/
void
AppendCopyBinaryHeaders(CopyOutState headerOutputState)
{
const int32 zero = 0;
MemoryContext oldContext = MemoryContextSwitchTo(headerOutputState->rowcontext);
/* Signature */
CopySendData(headerOutputState, BinarySignature, 11);
/* Flags field (no OIDs) */
CopySendInt32(headerOutputState, zero);
/* No header extension */
CopySendInt32(headerOutputState, zero);
MemoryContextSwitchTo(oldContext);
}
/*
* AppendCopyBinaryFooters appends binary footers to the copy buffer in
* footerOutputState.
*/
void
AppendCopyBinaryFooters(CopyOutState footerOutputState)
{
int16 negative = -1;
MemoryContext oldContext = MemoryContextSwitchTo(footerOutputState->rowcontext);
CopySendInt16(footerOutputState, negative);
MemoryContextSwitchTo(oldContext);
}
/* *INDENT-OFF* */
/*
* Send copy start/stop messages for frontend copies. These have changed
* in past protocol redesigns.
*/
static void
SendCopyBegin(CopyOutState cstate)
{
#if PG_VERSION_NUM < PG_VERSION_14
if (PG_PROTOCOL_MAJOR(FrontendProtocol) < 3) {
/* old way */
if (cstate->binary)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("COPY BINARY is not supported to stdout or from stdin")));
pq_putemptymessage('H');
/* grottiness needed for old COPY OUT protocol */
pq_startcopyout();
cstate->copy_dest = COPY_OLD_FE;
return;
}
#endif
StringInfoData buf;
int natts = list_length(cstate->attnumlist);
int16 format = (cstate->binary ? 1 : 0);
int i;
pq_beginmessage(&buf, 'H');
pq_sendbyte(&buf, format); /* overall format */
pq_sendint16(&buf, natts);
for (i = 0; i < natts; i++)
pq_sendint16(&buf, format); /* per-column formats */
pq_endmessage(&buf);
cstate->copy_dest = COPY_FRONTEND;
}
/* End a copy stream sent to the client */
static void
SendCopyEnd(CopyOutState cstate)
{
#if PG_VERSION_NUM < PG_VERSION_14
if (cstate->copy_dest != COPY_NEW_FE)
{
CopySendData(cstate, "\\.", 2);
/* Need to flush out the trailer (this also appends a newline) */
CopySendEndOfRow(cstate, true);
pq_endcopyout(false);
return;
}
#endif
/* Shouldn't have any unsent data */
Assert(cstate->fe_msgbuf->len == 0);
/* Send Copy Done message */
pq_putemptymessage('c');
}
/* Append data to the copy buffer in outputState */
static void
CopySendData(CopyOutState outputState, const void *databuf, int datasize)
{
appendBinaryStringInfo(outputState->fe_msgbuf, databuf, datasize);
}
/* Append a striong to the copy buffer in outputState. */
static void
CopySendString(CopyOutState outputState, const char *str)
{
appendBinaryStringInfo(outputState->fe_msgbuf, str, strlen(str));
}
/* Append a char to the copy buffer in outputState. */
static void
CopySendChar(CopyOutState outputState, char c)
{
appendStringInfoCharMacro(outputState->fe_msgbuf, c);
}
/* Append an int32 to the copy buffer in outputState. */
static void
CopySendInt32(CopyOutState outputState, int32 val)
{
uint32 buf = htonl((uint32) val);
CopySendData(outputState, &buf, sizeof(buf));
}
/* Append an int16 to the copy buffer in outputState. */
static void
CopySendInt16(CopyOutState outputState, int16 val)
{
uint16 buf = htons((uint16) val);
CopySendData(outputState, &buf, sizeof(buf));
}
/* Send the row to the appropriate destination */
static void
CopySendEndOfRow(CopyOutState cstate, bool includeEndOfLine)
{
StringInfo fe_msgbuf = cstate->fe_msgbuf;
switch (cstate->copy_dest)
{
#if PG_VERSION_NUM < PG_VERSION_14
case COPY_OLD_FE:
/* The FE/BE protocol uses \n as newline for all platforms */
if (!cstate->binary && includeEndOfLine)
CopySendChar(cstate, '\n');
if (pq_putbytes(fe_msgbuf->data, fe_msgbuf->len))
{
/* no hope of recovering connection sync, so FATAL */
ereport(FATAL,
(errcode(ERRCODE_CONNECTION_FAILURE),
errmsg("connection lost during COPY to stdout")));
}
break;
#endif
case COPY_FRONTEND:
/* The FE/BE protocol uses \n as newline for all platforms */
if (!cstate->binary && includeEndOfLine)
CopySendChar(cstate, '\n');
/* Dump the accumulated row as one CopyData message */
(void) pq_putmessage('d', fe_msgbuf->data, fe_msgbuf->len);
break;
case COPY_FILE:
case COPY_CALLBACK:
Assert(false); /* Not yet supported. */
break;
}
resetStringInfo(fe_msgbuf);
}
/*
* Send text representation of one column, with conversion and escaping.
*
* NB: This function is based on commands/copy.c and doesn't fully conform to
* our coding style. The function should be kept in sync with copy.c.
*/
static void
CopyAttributeOutText(CopyOutState cstate, char *string)
{
char *pointer = NULL;
char c = '\0';
char delimc = cstate->delim[0];
if (cstate->need_transcoding)
{
pointer = pg_server_to_any(string, strlen(string), cstate->file_encoding);
}
else
{
pointer = string;
}
/*
* We have to grovel through the string searching for control characters
* and instances of the delimiter character. In most cases, though, these
* are infrequent. To avoid overhead from calling CopySendData once per
* character, we dump out all characters between escaped characters in a
* single call. The loop invariant is that the data from "start" to "pointer"
* can be sent literally, but hasn't yet been.
*
* As all encodings here are safe, i.e. backend supported ones, we can
* skip doing pg_encoding_mblen(), because in valid backend encodings,
* extra bytes of a multibyte character never look like ASCII.
*/
char *start = pointer;
while ((c = *pointer) != '\0')
{
if ((unsigned char) c < (unsigned char) 0x20)
{
/*
* \r and \n must be escaped, the others are traditional. We
* prefer to dump these using the C-like notation, rather than
* a backslash and the literal character, because it makes the
* dump file a bit more proof against Microsoftish data
* mangling.
*/
switch (c)
{
case '\b':
c = 'b';
break;
case '\f':
c = 'f';
break;
case '\n':
c = 'n';
break;
case '\r':
c = 'r';
break;
case '\t':
c = 't';
break;
case '\v':
c = 'v';
break;
default:
/* If it's the delimiter, must backslash it */
if (c == delimc)
break;
/* All ASCII control chars are length 1 */
pointer++;
continue; /* fall to end of loop */
}
/* if we get here, we need to convert the control char */
CopyFlushOutput(cstate, start, pointer);
CopySendChar(cstate, '\\');
CopySendChar(cstate, c);
start = ++pointer; /* do not include char in next run */
}
else if (c == '\\' || c == delimc)
{
CopyFlushOutput(cstate, start, pointer);
CopySendChar(cstate, '\\');
start = pointer++; /* we include char in next run */
}
else
{
pointer++;
}
}
CopyFlushOutput(cstate, start, pointer);
}
/* *INDENT-ON* */
/* Helper function to send pending copy output */
static inline void
CopyFlushOutput(CopyOutState cstate, char *start, char *pointer)
{
if (pointer > start)
{
CopySendData(cstate, start, pointer - start);
}
}
/*
* CreateCitusCopyDestReceiver creates a DestReceiver that copies into
* a distributed table.
*
* The caller should provide the list of column names to use in the
* remote COPY statement, and the partition column index in the tuple
* descriptor (*not* the column name list).
*
* If intermediateResultIdPrefix is not NULL, the COPY will go into a set
* of intermediate results that are co-located with the actual table.
* The names of the intermediate results with be of the form:
* intermediateResultIdPrefix_<shardid>
*/
CitusCopyDestReceiver *
CreateCitusCopyDestReceiver(Oid tableId, List *columnNameList, int partitionColumnIndex,
EState *executorState,
char *intermediateResultIdPrefix, bool isPublishable)
{
CitusCopyDestReceiver *copyDest = (CitusCopyDestReceiver *) palloc0(
sizeof(CitusCopyDestReceiver));
/* set up the DestReceiver function pointers */
copyDest->pub.receiveSlot = CitusCopyDestReceiverReceive;
copyDest->pub.rStartup = CitusCopyDestReceiverStartup;
copyDest->pub.rShutdown = CitusCopyDestReceiverShutdown;
copyDest->pub.rDestroy = CitusCopyDestReceiverDestroy;
copyDest->pub.mydest = DestCopyOut;
/* set up output parameters */
copyDest->distributedRelationId = tableId;
copyDest->columnNameList = columnNameList;
copyDest->partitionColumnIndex = partitionColumnIndex;
copyDest->executorState = executorState;
copyDest->colocatedIntermediateResultIdPrefix = intermediateResultIdPrefix;
copyDest->memoryContext = CurrentMemoryContext;
copyDest->isPublishable = isPublishable;
return copyDest;
}
/*
* GetLocalCopyStatus returns the status for executing copy locally.
* If LOCAL_COPY_DISABLED or LOCAL_COPY_REQUIRED, the caller has to
* follow that. Else, the caller may decide to use local or remote
* execution depending on other information.
*/
static LocalCopyStatus
GetLocalCopyStatus(void)
{
if (!EnableLocalExecution ||
GetCurrentLocalExecutionStatus() == LOCAL_EXECUTION_DISABLED)
{
return LOCAL_COPY_DISABLED;
}
else if (GetCurrentLocalExecutionStatus() == LOCAL_EXECUTION_REQUIRED)
{
/*
* For various reasons, including the transaction visibility
* rules (e.g., read-your-own-writes), we have to use local
* execution again if it has already happened within this
* transaction block.
*
* We might error out later in the execution if it is not suitable
* to execute the tasks locally.
*/
Assert(IsMultiStatementTransaction() || InCoordinatedTransaction());
/*
* TODO: A future improvement could be to keep track of which placements
* have been locally executed. At this point, only use local execution for
* those placements. That'd help to benefit more from parallelism.
*/
return LOCAL_COPY_REQUIRED;
}
else if (IsMultiStatementTransaction())
{
return LOCAL_COPY_REQUIRED;
}
return LOCAL_COPY_OPTIONAL;
}
/*
* ShardIntervalListHasLocalPlacements returns true if any of the input
* shard placement has a local placement;
*/
static bool
ShardIntervalListHasLocalPlacements(List *shardIntervalList)
{
int32 localGroupId = GetLocalGroupId();
ShardInterval *shardInterval = NULL;
foreach_ptr(shardInterval, shardIntervalList)
{
if (ActiveShardPlacementOnGroup(localGroupId, shardInterval->shardId) != NULL)
{
return true;
}
}
return false;
}
/*
* CitusCopyDestReceiverStartup implements the rStartup interface of
* CitusCopyDestReceiver. It opens the relation, acquires necessary
* locks, and initializes the state required for doing the copy.
*/
static void
CitusCopyDestReceiverStartup(DestReceiver *dest, int operation,
TupleDesc inputTupleDescriptor)
{
CitusCopyDestReceiver *copyDest = (CitusCopyDestReceiver *) dest;
Oid tableId = copyDest->distributedRelationId;
char *relationName = get_rel_name(tableId);
Oid schemaOid = get_rel_namespace(tableId);
char *schemaName = get_namespace_name(schemaOid);
List *columnNameList = copyDest->columnNameList;
List *attributeList = NIL;
ListCell *columnNameCell = NULL;
const char *delimiterCharacter = "\t";
const char *nullPrintCharacter = "\\N";
/* look up table properties */
Relation distributedRelation = table_open(tableId, RowExclusiveLock);
CitusTableCacheEntry *cacheEntry = GetCitusTableCacheEntry(tableId);
copyDest->distributedRelation = distributedRelation;
copyDest->tupleDescriptor = inputTupleDescriptor;
/* load the list of shards and verify that we have shards to copy into */
List *shardIntervalList = LoadShardIntervalList(tableId);
if (shardIntervalList == NIL)
{
if (IsCitusTableTypeCacheEntry(cacheEntry, HASH_DISTRIBUTED))
{
ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("could not find any shards into which to copy"),
errdetail("No shards exist for distributed table \"%s\".",
relationName),
errhint("Run master_create_worker_shards to create shards "
"and try again.")));
}
else
{
ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("could not find any shards into which to copy"),
errdetail("No shards exist for distributed table \"%s\".",
relationName)));
}
}
/* error if any shard missing min/max values */
if (cacheEntry->hasUninitializedShardInterval)
{
if (IsCitusTableTypeCacheEntry(cacheEntry, HASH_DISTRIBUTED) ||
IsCitusTableTypeCacheEntry(cacheEntry, RANGE_DISTRIBUTED))
{
ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("could not start copy"),
errdetail("Distributed relation \"%s\" has shards "
"with missing shardminvalue/shardmaxvalue.",
relationName)));
}
}
/* prevent concurrent placement changes and non-commutative DML statements */
LockShardListMetadata(shardIntervalList, ShareLock);
/*
* Prevent concurrent UPDATE/DELETE on replication factor >1
* (see AcquireExecutorMultiShardLocks() at multi_router_executor.c)
*/
SerializeNonCommutativeWrites(shardIntervalList, RowExclusiveLock);
UseCoordinatedTransaction();
/* all modifications use 2PC */
Use2PCForCoordinatedTransaction();
/* define how tuples will be serialised */
CopyOutState copyOutState = (CopyOutState) palloc0(sizeof(CopyOutStateData));
copyOutState->delim = (char *) delimiterCharacter;
copyOutState->null_print = (char *) nullPrintCharacter;
copyOutState->null_print_client = (char *) nullPrintCharacter;
copyOutState->binary = CanUseBinaryCopyFormat(inputTupleDescriptor);
copyOutState->fe_msgbuf = makeStringInfo();
copyOutState->rowcontext = GetPerTupleMemoryContext(copyDest->executorState);
copyDest->copyOutState = copyOutState;
copyDest->multiShardCopy = false;
/* prepare functions to call on received tuples */
{
TupleDesc destTupleDescriptor = distributedRelation->rd_att;
int columnCount = inputTupleDescriptor->natts;
Oid *finalTypeArray = palloc0(columnCount * sizeof(Oid));
copyDest->columnCoercionPaths =
ColumnCoercionPaths(destTupleDescriptor, inputTupleDescriptor,
tableId, columnNameList, finalTypeArray);
copyDest->columnOutputFunctions =
TypeOutputFunctions(columnCount, finalTypeArray, copyOutState->binary);
}
/* wrap the column names as Values */
foreach(columnNameCell, columnNameList)
{
char *columnName = (char *) lfirst(columnNameCell);
String *columnNameValue = makeString(columnName);
attributeList = lappend(attributeList, columnNameValue);
}
if (IsCitusTableTypeCacheEntry(cacheEntry, DISTRIBUTED_TABLE) &&
!IsCitusTableTypeCacheEntry(cacheEntry, SINGLE_SHARD_DISTRIBUTED) &&
copyDest->partitionColumnIndex == INVALID_PARTITION_COLUMN_INDEX)
{
ereport(ERROR, (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("the partition column of table %s should have a value",
quote_qualified_identifier(schemaName, relationName))));
}
/* define the template for the COPY statement that is sent to workers */
CopyStmt *copyStatement = makeNode(CopyStmt);
bool colocatedIntermediateResults =
copyDest->colocatedIntermediateResultIdPrefix != NULL;
if (colocatedIntermediateResults)
{
copyStatement->relation = makeRangeVar(NULL,
copyDest->
colocatedIntermediateResultIdPrefix,
-1);
DefElem *formatResultOption = makeDefElem("format", (Node *) makeString("result"),
-1);
copyStatement->options = list_make1(formatResultOption);
}
else
{
copyStatement->relation = makeRangeVar(schemaName, relationName, -1);
copyStatement->options = NIL;
if (copyOutState->binary)
{
DefElem *binaryFormatOption =
makeDefElem("format", (Node *) makeString("binary"), -1);
copyStatement->options = lappend(copyStatement->options, binaryFormatOption);
}
}
copyStatement->query = NULL;
copyStatement->attlist = attributeList;
copyStatement->is_from = true;
copyStatement->is_program = false;
copyStatement->filename = NULL;
copyDest->copyStatement = copyStatement;
copyDest->shardStateHash = CreateShardStateHash(TopTransactionContext);
copyDest->connectionStateHash = CreateConnectionStateHash(TopTransactionContext);
RecordRelationAccessIfNonDistTable(tableId, PLACEMENT_ACCESS_DML);
/*
* Colocated intermediate results do not honor citus.max_shared_pool_size,
* so we don't need to reserve any connections. Each result file is sent
* over a single connection.
*/
if (!colocatedIntermediateResults)
{
/*
* For all the primary (e.g., writable) remote nodes, reserve a shared
* connection. We do this upfront because we cannot know which nodes
* are going to be accessed. Since the order of the reservation is
* important, we need to do it right here. For the details on why the
* order important, see EnsureConnectionPossibilityForNodeList().
*
* We don't need to care about local node because we either get a
* connection or use local connection, so it cannot be part of
* the starvation. As an edge case, if it cannot get a connection
* and cannot switch to local execution (e.g., disabled by user),
* COPY would fail hinting the user to change the relevant settiing.
*/
EnsureConnectionPossibilityForRemotePrimaryNodes();
}
LocalCopyStatus localCopyStatus = GetLocalCopyStatus();
if (localCopyStatus == LOCAL_COPY_DISABLED)
{
copyDest->shouldUseLocalCopy = false;
}
else if (localCopyStatus == LOCAL_COPY_REQUIRED)
{
copyDest->shouldUseLocalCopy = true;
}
else if (localCopyStatus == LOCAL_COPY_OPTIONAL)
{
/*
* At this point, there is no requirements for doing the copy locally.
* However, if there are local placements, we can try to reserve
* a connection to local node. If we cannot reserve, we can still use
* local execution.
*
* NB: It is not advantageous to use remote execution just with a
* single remote connection. In other words, a single remote connection
* would not perform better than local execution. However, we prefer to
* do this because it is likely that the COPY would get more connections
* to parallelize the operation. In the future, we might relax this
* requirement and failover to local execution as on connection attempt
* failures as the executor does.
*/
if (ShardIntervalListHasLocalPlacements(shardIntervalList))
{
bool reservedConnection = TryConnectionPossibilityForLocalPrimaryNode();
copyDest->shouldUseLocalCopy = !reservedConnection;
}
}
}
/*
* CitusCopyDestReceiverReceive implements the receiveSlot function of
* CitusCopyDestReceiver. It takes a TupleTableSlot and sends the contents to
* the appropriate shard placement(s).
*/
static bool
CitusCopyDestReceiverReceive(TupleTableSlot *slot, DestReceiver *dest)
{
bool result = false;
CitusCopyDestReceiver *copyDest = (CitusCopyDestReceiver *) dest;
PG_TRY();
{
result = CitusSendTupleToPlacements(slot, copyDest);
}
PG_CATCH();
{
/*
* We might be able to recover from errors with ROLLBACK TO SAVEPOINT,
* so unclaim the connections before throwing errors.
*/
List *connectionStateList = ConnectionStateList(copyDest->connectionStateHash);
UnclaimCopyConnections(connectionStateList);
PG_RE_THROW();
}
PG_END_TRY();
return result;
}
/*
* CitusSendTupleToPlacements sends the given TupleTableSlot to the appropriate
* shard placement(s).
*/
static bool
CitusSendTupleToPlacements(TupleTableSlot *slot, CitusCopyDestReceiver *copyDest)
{
TupleDesc tupleDescriptor = copyDest->tupleDescriptor;
CopyStmt *copyStatement = copyDest->copyStatement;
CopyOutState copyOutState = copyDest->copyOutState;
FmgrInfo *columnOutputFunctions = copyDest->columnOutputFunctions;
CopyCoercionData *columnCoercionPaths = copyDest->columnCoercionPaths;
ListCell *placementStateCell = NULL;
bool cachedShardStateFound = false;
bool firstTupleInShard = false;
EState *executorState = copyDest->executorState;
MemoryContext executorTupleContext = GetPerTupleMemoryContext(executorState);
MemoryContext oldContext = MemoryContextSwitchTo(executorTupleContext);
slot_getallattrs(slot);
Datum *columnValues = slot->tts_values;
bool *columnNulls = slot->tts_isnull;
int64 shardId = ShardIdForTuple(copyDest, columnValues, columnNulls);
/* connections hash is kept in memory context */
MemoryContextSwitchTo(copyDest->memoryContext);
bool isColocatedIntermediateResult =
copyDest->colocatedIntermediateResultIdPrefix != NULL;
CopyShardState *shardState = GetShardState(shardId, copyDest->shardStateHash,
copyDest->connectionStateHash,
&cachedShardStateFound,
copyDest->shouldUseLocalCopy,
copyDest->copyOutState,
isColocatedIntermediateResult,
copyDest->isPublishable);
if (!cachedShardStateFound)
{
firstTupleInShard = true;
}
if (firstTupleInShard && !copyDest->multiShardCopy &&
hash_get_num_entries(copyDest->shardStateHash) == 2)
{
Oid relationId = copyDest->distributedRelationId;
/* mark as multi shard to skip doing the same thing over and over */
copyDest->multiShardCopy = true;
if (MultiShardConnectionType != SEQUENTIAL_CONNECTION)
{
/* when we see multiple shard connections, we mark COPY as parallel modify */
RecordParallelModifyAccess(relationId);
}
}
if (isColocatedIntermediateResult && copyDest->shouldUseLocalCopy &&
shardState->containsLocalPlacement)
{
if (firstTupleInShard)
{
CreateLocalColocatedIntermediateFile(copyDest, shardState);
}
WriteTupleToLocalFile(slot, copyDest, shardId,
shardState->copyOutState, &shardState->fileDest);
}
else if (copyDest->shouldUseLocalCopy && shardState->containsLocalPlacement)
{
WriteTupleToLocalShard(slot, copyDest, shardId, shardState->copyOutState);
}
foreach(placementStateCell, shardState->placementStateList)
{
CopyPlacementState *currentPlacementState = lfirst(placementStateCell);
CopyConnectionState *connectionState = currentPlacementState->connectionState;
CopyPlacementState *activePlacementState = connectionState->activePlacementState;
bool switchToCurrentPlacement = false;
bool sendTupleOverConnection = false;
if (activePlacementState == NULL)
{
switchToCurrentPlacement = true;
}
else if (currentPlacementState != activePlacementState &&
currentPlacementState->data->len > CopySwitchOverThresholdBytes)
{
switchToCurrentPlacement = true;
/* before switching, make sure to finish the copy */
EndPlacementStateCopyCommand(activePlacementState, copyOutState);
AddPlacementStateToCopyConnectionStateBuffer(connectionState,
activePlacementState);
}
if (switchToCurrentPlacement)
{
StartPlacementStateCopyCommand(currentPlacementState, copyStatement,
copyOutState);
RemovePlacementStateFromCopyConnectionStateBuffer(connectionState,
currentPlacementState);
connectionState->activePlacementState = currentPlacementState;
/* send previously buffered tuples */
SendCopyDataToPlacement(currentPlacementState->data, shardId,
connectionState->connection);
resetStringInfo(currentPlacementState->data);
/* additionaly, we need to send the current tuple too */
sendTupleOverConnection = true;
}
else if (currentPlacementState != activePlacementState)
{
/* buffer data */
StringInfo copyBuffer = copyOutState->fe_msgbuf;
resetStringInfo(copyBuffer);
AppendCopyRowData(columnValues, columnNulls, tupleDescriptor,
copyOutState, columnOutputFunctions,
columnCoercionPaths);
appendBinaryStringInfo(currentPlacementState->data, copyBuffer->data,
copyBuffer->len);
}
else
{
Assert(currentPlacementState == activePlacementState);
sendTupleOverConnection = true;
}
if (sendTupleOverConnection)
{
resetStringInfo(copyOutState->fe_msgbuf);
AppendCopyRowData(columnValues, columnNulls, tupleDescriptor,
copyOutState, columnOutputFunctions, columnCoercionPaths);
SendCopyDataToPlacement(copyOutState->fe_msgbuf, shardId,
connectionState->connection);
}
}
MemoryContextSwitchTo(oldContext);
copyDest->tuplesSent++;
/*
* Release per tuple memory allocated in this function. If we're writing
* the results of an INSERT ... SELECT then the SELECT execution will use
* its own executor state and reset the per tuple expression context
* separately.
*/
ResetPerTupleExprContext(executorState);
return true;
}
/*
* AddPlacementStateToCopyConnectionStateBuffer is a helper function to add a placement
* state to connection state's placement buffer. In addition to that, keep the counter
* up to date.
*/
static void
AddPlacementStateToCopyConnectionStateBuffer(CopyConnectionState *connectionState,
CopyPlacementState *placementState)
{
dlist_push_head(&connectionState->bufferedPlacementList,
&placementState->bufferedPlacementNode);
connectionState->bufferedPlacementCount++;
}
/*
* RemovePlacementStateFromCopyConnectionStateBuffer is a helper function to removes a placement
* state from connection state's placement buffer. In addition to that, keep the counter
* up to date.
*/
static void
RemovePlacementStateFromCopyConnectionStateBuffer(CopyConnectionState *connectionState,
CopyPlacementState *placementState)
{
dlist_delete(&placementState->bufferedPlacementNode);
connectionState->bufferedPlacementCount--;
}
/*
* ProcessAppendToShardOption returns the value of append_to_shard if set,
* and removes the option from the options list.
*/
static uint64
ProcessAppendToShardOption(Oid relationId, CopyStmt *copyStatement)
{
uint64 appendShardId = INVALID_SHARD_ID;
bool appendToShardSet = false;
DefElem *defel = NULL;
foreach_ptr(defel, copyStatement->options)
{
if (strncmp(defel->defname, APPEND_TO_SHARD_OPTION, NAMEDATALEN) == 0)
{
appendShardId = defGetInt64(defel);
appendToShardSet = true;
break;
}
}
if (appendToShardSet)
{
if (!IsCitusTableType(relationId, APPEND_DISTRIBUTED))
{
ereport(ERROR, (errmsg(APPEND_TO_SHARD_OPTION " is only valid for "
"append-distributed tables")));
}
/* throws an error if shard does not exist */
ShardInterval *shardInterval = LoadShardInterval(appendShardId);
/* also check whether shard belongs to table */
if (shardInterval->relationId != relationId)
{
ereport(ERROR, (errmsg("shard " UINT64_FORMAT " does not belong to table %s",
appendShardId, get_rel_name(relationId))));
}
copyStatement->options =
RemoveOptionFromList(copyStatement->options, APPEND_TO_SHARD_OPTION);
}
else if (IsCitusTableType(relationId, APPEND_DISTRIBUTED))
{
ereport(ERROR, (errmsg("COPY into append-distributed table requires using the "
APPEND_TO_SHARD_OPTION " option")));
}
return appendShardId;
}
/*
* ContainsLocalPlacement returns true if the current node has
* a local placement for the given shard id.
*/
static bool
ContainsLocalPlacement(int64 shardId)
{
ListCell *placementCell = NULL;
List *activePlacementList = ActiveShardPlacementList(shardId);
int32 localGroupId = GetLocalGroupId();
foreach(placementCell, activePlacementList)
{
ShardPlacement *placement = (ShardPlacement *) lfirst(placementCell);
if (placement->groupId == localGroupId)
{
return true;
}
}
return false;
}
/*
* ShardIdForTuple returns id of the shard to which the given tuple belongs to.
*/
static uint64
ShardIdForTuple(CitusCopyDestReceiver *copyDest, Datum *columnValues, bool *columnNulls)
{
int partitionColumnIndex = copyDest->partitionColumnIndex;
Datum partitionColumnValue = 0;
CopyCoercionData *columnCoercionPaths = copyDest->columnCoercionPaths;
CitusTableCacheEntry *cacheEntry =
GetCitusTableCacheEntry(copyDest->distributedRelationId);
if (IsCitusTableTypeCacheEntry(cacheEntry, APPEND_DISTRIBUTED))
{
return copyDest->appendShardId;
}
/*
* Find the partition column value and corresponding shard interval
* for non-reference tables.
* Get the existing (and only a single) shard interval for the reference
* tables. Note that, reference tables has NULL partition column values so
* skip the check.
*/
if (partitionColumnIndex != INVALID_PARTITION_COLUMN_INDEX)
{
CopyCoercionData *coercePath = &columnCoercionPaths[partitionColumnIndex];
if (columnNulls[partitionColumnIndex])
{
Oid relationId = copyDest->distributedRelationId;
char *relationName = get_rel_name(relationId);
Oid schemaOid = get_rel_namespace(relationId);
char *schemaName = get_namespace_name(schemaOid);
char *qualifiedTableName = quote_qualified_identifier(schemaName,
relationName);
ereport(ERROR, (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("the partition column of table %s cannot be NULL",
qualifiedTableName)));
}
/* find the partition column value */
partitionColumnValue = columnValues[partitionColumnIndex];
/* annoyingly this is evaluated twice, but at least we don't crash! */
partitionColumnValue = CoerceColumnValue(partitionColumnValue, coercePath);
}
/*
* Find the shard interval and id for the partition column value for
* non-reference tables.
*
* For reference table, this function blindly returns the tables single
* shard.
*/
ShardInterval *shardInterval = FindShardInterval(partitionColumnValue, cacheEntry);
if (shardInterval == NULL)
{
ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("could not find shard for partition column "
"value")));
}
return shardInterval->shardId;
}
/*
* CitusCopyDestReceiverShutdown implements the rShutdown interface of
* CitusCopyDestReceiver. It ends the COPY on all the open connections and closes
* the relation.
*/
static void
CitusCopyDestReceiverShutdown(DestReceiver *destReceiver)
{
CitusCopyDestReceiver *copyDest = (CitusCopyDestReceiver *) destReceiver;
HTAB *connectionStateHash = copyDest->connectionStateHash;
ListCell *connectionStateCell = NULL;
Relation distributedRelation = copyDest->distributedRelation;
List *connectionStateList = ConnectionStateList(connectionStateHash);
FinishLocalColocatedIntermediateFiles(copyDest);
FinishLocalCopy(copyDest);
PG_TRY();
{
foreach(connectionStateCell, connectionStateList)
{
CopyConnectionState *connectionState =
(CopyConnectionState *) lfirst(connectionStateCell);
ShutdownCopyConnectionState(connectionState, copyDest);
}
}
PG_CATCH();
{
/*
* We might be able to recover from errors with ROLLBACK TO SAVEPOINT,
* so unclaim the connections before throwing errors.
*/
UnclaimCopyConnections(connectionStateList);
PG_RE_THROW();
}
PG_END_TRY();
table_close(distributedRelation, NoLock);
}
/*
* FinishLocalCopy sends the remaining copies for local placements.
*/
static void
FinishLocalCopy(CitusCopyDestReceiver *copyDest)
{
HTAB *shardStateHash = copyDest->shardStateHash;
HASH_SEQ_STATUS status;
CopyShardState *copyShardState;
foreach_htab(copyShardState, &status, shardStateHash)
{
if (copyShardState->copyOutState != NULL &&
copyShardState->copyOutState->fe_msgbuf->len > 0)
{
FinishLocalCopyToShard(copyDest, copyShardState->shardId,
copyShardState->copyOutState);
}
}
}
/*
* CreateLocalColocatedIntermediateFile creates a co-located file for the given
* shard, and appends the binary headers if needed. The function also modifies
* shardState to set the fileDest and copyOutState.
*/
static void
CreateLocalColocatedIntermediateFile(CitusCopyDestReceiver *copyDest,
CopyShardState *shardState)
{
/* make sure the directory exists */
CreateIntermediateResultsDirectory();
const int fileFlags = (O_CREAT | O_RDWR | O_TRUNC);
const int fileMode = (S_IRUSR | S_IWUSR);
StringInfo filePath = makeStringInfo();
appendStringInfo(filePath, "%s_%ld", copyDest->colocatedIntermediateResultIdPrefix,
shardState->shardId);
const char *fileName = QueryResultFileName(filePath->data);
shardState->fileDest =
FileCompatFromFileStart(FileOpenForTransmit(fileName, fileFlags, fileMode));
CopyOutState localFileCopyOutState = shardState->copyOutState;
bool isBinaryCopy = localFileCopyOutState->binary;
if (isBinaryCopy)
{
AppendCopyBinaryHeaders(localFileCopyOutState);
}
}
/*
* FinishLocalColocatedIntermediateFiles iterates over all the colocated
* intermediate files and finishes the COPY on all of them.
*/
static void
FinishLocalColocatedIntermediateFiles(CitusCopyDestReceiver *copyDest)
{
HTAB *shardStateHash = copyDest->shardStateHash;
HASH_SEQ_STATUS status;
CopyShardState *copyShardState;
foreach_htab(copyShardState, &status, shardStateHash)
{
if (copyShardState->copyOutState != NULL &&
FILE_IS_OPEN(copyShardState->fileDest.fd))
{
FinishLocalCopyToFile(copyShardState->copyOutState,
&copyShardState->fileDest);
}
}
}
/*
* ShutdownCopyConnectionState ends the copy command for the current active
* placement on connection, and then sends the rest of the buffers over the
* connection.
*/
static void
ShutdownCopyConnectionState(CopyConnectionState *connectionState,
CitusCopyDestReceiver *copyDest)
{
CopyOutState copyOutState = copyDest->copyOutState;
CopyStmt *copyStatement = copyDest->copyStatement;
dlist_iter iter;
CopyPlacementState *activePlacementState = connectionState->activePlacementState;
if (activePlacementState != NULL)
{
EndPlacementStateCopyCommand(activePlacementState, copyOutState);
if (!copyDest->isPublishable)
{
ResetReplicationOriginRemoteSession(
activePlacementState->connectionState->connection);
}
}
dlist_foreach(iter, &connectionState->bufferedPlacementList)
{
CopyPlacementState *placementState =
dlist_container(CopyPlacementState, bufferedPlacementNode, iter.cur);
uint64 shardId = placementState->shardState->shardId;
StartPlacementStateCopyCommand(placementState, copyStatement,
copyOutState);
SendCopyDataToPlacement(placementState->data, shardId,
connectionState->connection);
EndPlacementStateCopyCommand(placementState, copyOutState);
if (!copyDest->isPublishable)
{
ResetReplicationOriginRemoteSession(connectionState->connection);
}
}
}
/*
* CitusCopyDestReceiverDestroy frees the DestReceiver
*/
static void
CitusCopyDestReceiverDestroy(DestReceiver *destReceiver)
{
CitusCopyDestReceiver *copyDest = (CitusCopyDestReceiver *) destReceiver;
if (copyDest->copyOutState)
{
pfree(copyDest->copyOutState);
}
if (copyDest->columnOutputFunctions)
{
pfree(copyDest->columnOutputFunctions);
}
if (copyDest->columnCoercionPaths)
{
pfree(copyDest->columnCoercionPaths);
}
if (copyDest->shardStateHash)
{
hash_destroy(copyDest->shardStateHash);
}
if (copyDest->connectionStateHash)
{
hash_destroy(copyDest->connectionStateHash);
}
pfree(copyDest);
}
/*
* IsCopyResultStmt determines whether the given copy statement is a
* COPY "resultkey" FROM STDIN WITH (format result) statement, which is used
* to copy query results from the coordinator into workers.
*/
bool
IsCopyResultStmt(CopyStmt *copyStatement)
{
return CopyStatementHasFormat(copyStatement, "result");
}
/*
* CopyStatementHasFormat checks whether the COPY statement has the given
* format.
*/
static bool
CopyStatementHasFormat(CopyStmt *copyStatement, char *formatName)
{
ListCell *optionCell = NULL;
bool hasFormat = false;
/* extract WITH (...) options from the COPY statement */
foreach(optionCell, copyStatement->options)
{
DefElem *defel = (DefElem *) lfirst(optionCell);
if (strncmp(defel->defname, "format", NAMEDATALEN) == 0 &&
strncmp(defGetString(defel), formatName, NAMEDATALEN) == 0)
{
hasFormat = true;
break;
}
}
return hasFormat;
}
/*
* ProcessCopyStmt handles Citus specific concerns for COPY like supporting
* COPYing from distributed tables and preventing unsupported actions. The
* function returns a modified COPY statement to be executed, or NULL if no
* further processing is needed.
*/
Node *
ProcessCopyStmt(CopyStmt *copyStatement, QueryCompletion *completionTag, const
char *queryString)
{
/*
* Handle special COPY "resultid" FROM STDIN WITH (format result) commands
* for sending intermediate results to workers.
*/
if (IsCopyResultStmt(copyStatement))
{
const char *resultId = copyStatement->relation->relname;
if (copyStatement->is_from)
{
ReceiveQueryResultViaCopy(resultId);
}
else
{
SendQueryResultViaCopy(resultId);
}
return NULL;
}
/*
* We check whether a distributed relation is affected. For that, we need to open the
* relation. To prevent race conditions with later lookups, lock the table, and modify
* the rangevar to include the schema.
*/
if (copyStatement->relation != NULL)
{
bool isFrom = copyStatement->is_from;
/* consider using RangeVarGetRelidExtended to check perms before locking */
Relation copiedRelation = table_openrv(copyStatement->relation,
isFrom ? RowExclusiveLock :
AccessShareLock);
bool isCitusRelation = IsCitusTable(RelationGetRelid(copiedRelation));
/* ensure future lookups hit the same relation */
char *schemaName = get_namespace_name(RelationGetNamespace(copiedRelation));
/* ensure we copy string into proper context */
MemoryContext relationContext = GetMemoryChunkContext(
copyStatement->relation);
schemaName = MemoryContextStrdup(relationContext, schemaName);
copyStatement->relation->schemaname = schemaName;
table_close(copiedRelation, NoLock);
if (isCitusRelation)
{
if (copyStatement->is_from)
{
if (copyStatement->whereClause)
{
/*
* Update progress reporting for tuples progressed so that the
* progress is reflected on pg_stat_progress_copy. Citus currently
* does not support COPY .. WHERE clause so TUPLES_EXCLUDED is not
* handled. When we remove this check, we should implement progress
* reporting as well.
*/
ereport(ERROR, (errmsg(
"Citus does not support COPY FROM with WHERE")));
}
/* check permissions, we're bypassing postgres' normal checks */
CheckCopyPermissions(copyStatement);
CitusCopyFrom(copyStatement, completionTag);
return NULL;
}
else if (copyStatement->filename == NULL && !copyStatement->is_program &&
!CopyStatementHasFormat(copyStatement, "binary"))
{
/*
* COPY table TO STDOUT is handled by specialized logic to
* avoid buffering the table on the coordinator. This enables
* pg_dump of large tables.
*/
CitusCopyTo(copyStatement, completionTag);
return NULL;
}
else
{
/*
* COPY table TO PROGRAM / file is handled by wrapping the table
* in a SELECT and going through the resulting COPY logic.
*/
SelectStmt *selectStmt = CitusCopySelect(copyStatement);
/* replace original statement */
copyStatement = copyObject(copyStatement);
copyStatement->relation = NULL;
copyStatement->query = (Node *) selectStmt;
}
}
}
return (Node *) copyStatement;
}
/*
* CitusCopySelect generates a SelectStmt such that table may be replaced in
* "COPY table FROM" for an equivalent result.
*/
static SelectStmt *
CitusCopySelect(CopyStmt *copyStatement)
{
SelectStmt *selectStmt = makeNode(SelectStmt);
selectStmt->fromClause = list_make1(copyObject(copyStatement->relation));
Relation distributedRelation = table_openrv(copyStatement->relation, AccessShareLock);
TupleDesc tupleDescriptor = RelationGetDescr(distributedRelation);
List *targetList = NIL;
for (int i = 0; i < tupleDescriptor->natts; i++)
{
Form_pg_attribute attr = &tupleDescriptor->attrs[i];
if (attr->attisdropped ||
attr->attgenerated
)
{
continue;
}
ColumnRef *column = makeNode(ColumnRef);
column->fields = list_make1(makeString(pstrdup(attr->attname.data)));
column->location = -1;
ResTarget *selectTarget = makeNode(ResTarget);
selectTarget->name = NULL;
selectTarget->indirection = NIL;
selectTarget->val = (Node *) column;
selectTarget->location = -1;
targetList = lappend(targetList, selectTarget);
}
table_close(distributedRelation, NoLock);
selectStmt->targetList = targetList;
return selectStmt;
}
/*
* CitusCopyTo runs a COPY .. TO STDOUT command on each shard to do a full
* table dump.
*/
static void
CitusCopyTo(CopyStmt *copyStatement, QueryCompletion *completionTag)
{
ListCell *shardIntervalCell = NULL;
int64 tuplesSent = 0;
Relation distributedRelation = table_openrv(copyStatement->relation, AccessShareLock);
Oid relationId = RelationGetRelid(distributedRelation);
TupleDesc tupleDescriptor = RelationGetDescr(distributedRelation);
CopyOutState copyOutState = (CopyOutState) palloc0(sizeof(CopyOutStateData));
copyOutState->fe_msgbuf = makeStringInfo();
copyOutState->binary = false;
copyOutState->attnumlist = CopyGetAttnums(tupleDescriptor, distributedRelation,
copyStatement->attlist);
SendCopyBegin(copyOutState);
List *shardIntervalList = LoadShardIntervalList(relationId);
foreach(shardIntervalCell, shardIntervalList)
{
ShardInterval *shardInterval = lfirst(shardIntervalCell);
List *shardPlacementList = ActiveShardPlacementList(shardInterval->shardId);
ListCell *shardPlacementCell = NULL;
int placementIndex = 0;
StringInfo copyCommand = ConstructCopyStatement(copyStatement,
shardInterval->shardId);
foreach(shardPlacementCell, shardPlacementList)
{
ShardPlacement *shardPlacement = lfirst(shardPlacementCell);
int connectionFlags = 0;
char *userName = NULL;
const bool raiseErrors = true;
MultiConnection *connection = GetPlacementConnection(connectionFlags,
shardPlacement,
userName);
/*
* This code-path doesn't support optional connections, so we don't expect
* NULL connections.
*/
Assert(connection != NULL);
if (placementIndex == list_length(shardPlacementList) - 1)
{
/* last chance for this shard */
MarkRemoteTransactionCritical(connection);
}
if (PQstatus(connection->pgConn) != CONNECTION_OK)
{
ReportConnectionError(connection, ERROR);
continue;
}
RemoteTransactionBeginIfNecessary(connection);
if (!SendRemoteCommand(connection, copyCommand->data))
{
ReportConnectionError(connection, ERROR);
continue;
}
PGresult *result = GetRemoteCommandResult(connection, raiseErrors);
if (PQresultStatus(result) != PGRES_COPY_OUT)
{
ReportResultError(connection, result, ERROR);
}
PQclear(result);
tuplesSent += ForwardCopyDataFromConnection(copyOutState, connection);
break;
}
if (shardIntervalCell == list_head(shardIntervalList))
{
/* remove header after the first shard */
copyStatement->options =
RemoveOptionFromList(copyStatement->options, "header");
}
}
SendCopyEnd(copyOutState);
table_close(distributedRelation, AccessShareLock);
if (completionTag != NULL)
{
CompleteCopyQueryTagCompat(completionTag, tuplesSent);
}
}
/*
* ForwardCopyDataFromConnection forwards copy data received over the given connection
* to the client or file descriptor.
*/
static int64
ForwardCopyDataFromConnection(CopyOutState copyOutState, MultiConnection *connection)
{
char *receiveBuffer = NULL;
const int useAsync = 0;
bool raiseErrors = true;
int64 tuplesSent = 0;
/* receive copy data message in a synchronous manner */
int receiveLength = PQgetCopyData(connection->pgConn, &receiveBuffer, useAsync);
while (receiveLength > 0)
{
bool includeEndOfLine = false;
CopySendData(copyOutState, receiveBuffer, receiveLength);
CopySendEndOfRow(copyOutState, includeEndOfLine);
tuplesSent++;
PQfreemem(receiveBuffer);
receiveLength = PQgetCopyData(connection->pgConn, &receiveBuffer, useAsync);
}
if (receiveLength != -1)
{
ReportConnectionError(connection, ERROR);
}
PGresult *result = GetRemoteCommandResult(connection, raiseErrors);
if (!IsResponseOK(result))
{
ReportResultError(connection, result, ERROR);
}
PQclear(result);
ClearResults(connection, raiseErrors);
return tuplesSent;
}
/*
* Check whether the current user has the permission to execute a COPY
* statement, raise ERROR if not. In some cases we have to do this separately
* from postgres' copy.c, because we have to execute the copy with elevated
* privileges.
*
* Copied from postgres, where it's part of DoCopy().
*/
void
CheckCopyPermissions(CopyStmt *copyStatement)
{
/* *INDENT-OFF* */
bool is_from = copyStatement->is_from;
Relation rel;
List *range_table = NIL;
TupleDesc tupDesc;
AclMode required_access = (is_from ? ACL_INSERT : ACL_SELECT);
List *attnums;
ListCell *cur;
rel = table_openrv(copyStatement->relation,
is_from ? RowExclusiveLock : AccessShareLock);
range_table = CreateRangeTable(rel, required_access);
RangeTblEntry *rte = (RangeTblEntry*) linitial(range_table);
tupDesc = RelationGetDescr(rel);
attnums = CopyGetAttnums(tupDesc, rel, copyStatement->attlist);
foreach(cur, attnums)
{
int attno = lfirst_int(cur) - FirstLowInvalidHeapAttributeNumber;
if (is_from)
{
rte->insertedCols = bms_add_member(rte->insertedCols, attno);
}
else
{
rte->selectedCols = bms_add_member(rte->selectedCols, attno);
}
}
ExecCheckRTPerms(range_table, true);
/* TODO: Perform RLS checks once supported */
table_close(rel, NoLock);
/* *INDENT-ON* */
}
/*
* CreateRangeTable creates a range table with the given relation.
*/
List *
CreateRangeTable(Relation rel, AclMode requiredAccess)
{
RangeTblEntry *rte = makeNode(RangeTblEntry);
rte->rtekind = RTE_RELATION;
rte->relid = rel->rd_id;
rte->relkind = rel->rd_rel->relkind;
rte->requiredPerms = requiredAccess;
return list_make1(rte);
}
#if PG_VERSION_NUM < PG_VERSION_14
/* Helper for CheckCopyPermissions(), copied from postgres */
static List *
CopyGetAttnums(TupleDesc tupDesc, Relation rel, List *attnamelist)
{
/* *INDENT-OFF* */
List *attnums = NIL;
if (attnamelist == NIL)
{
/* Generate default column list */
int attr_count = tupDesc->natts;
int i;
for (i = 0; i < attr_count; i++)
{
if (TupleDescAttr(tupDesc, i)->attisdropped)
continue;
if (TupleDescAttr(tupDesc, i)->attgenerated)
continue;
attnums = lappend_int(attnums, i + 1);
}
}
else
{
/* Validate the user-supplied list and extract attnums */
ListCell *l;
foreach(l, attnamelist)
{
char *name = strVal(lfirst(l));
int attnum;
int i;
/* Lookup column name */
attnum = InvalidAttrNumber;
for (i = 0; i < tupDesc->natts; i++)
{
Form_pg_attribute att = TupleDescAttr(tupDesc, i);
if (att->attisdropped)
continue;
if (namestrcmp(&(att->attname), name) == 0)
{
if (att->attgenerated)
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("column \"%s\" is a generated column",
name),
errdetail("Generated columns cannot be used in COPY.")));
attnum = att->attnum;
break;
}
}
if (attnum == InvalidAttrNumber)
{
if (rel != NULL)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
name, RelationGetRelationName(rel))));
else
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" does not exist",
name)));
}
/* Check for duplicates */
if (list_member_int(attnums, attnum))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_COLUMN),
errmsg("column \"%s\" specified more than once",
name)));
attnums = lappend_int(attnums, attnum);
}
}
return attnums;
/* *INDENT-ON* */
}
#endif
/*
* CreateConnectionStateHash constructs a hash table which maps from socket
* number to CopyConnectionState, passing the provided MemoryContext to
* hash_create for hash allocations.
*/
static HTAB *
CreateConnectionStateHash(MemoryContext memoryContext)
{
HASHCTL info;
memset(&info, 0, sizeof(info));
info.keysize = sizeof(int);
info.entrysize = sizeof(CopyConnectionState);
info.hcxt = memoryContext;
int hashFlags = (HASH_ELEM | HASH_CONTEXT | HASH_BLOBS);
HTAB *connectionStateHash = hash_create("Copy Connection State Hash", 128, &info,
hashFlags);
return connectionStateHash;
}
/*
* CreateShardStateHash constructs a hash table which maps from shard
* identifier to CopyShardState, passing the provided MemoryContext to
* hash_create for hash allocations.
*/
static HTAB *
CreateShardStateHash(MemoryContext memoryContext)
{
HASHCTL info;
memset(&info, 0, sizeof(info));
info.keysize = sizeof(uint64);
info.entrysize = sizeof(CopyShardState);
info.hcxt = memoryContext;
int hashFlags = (HASH_ELEM | HASH_CONTEXT | HASH_BLOBS);
HTAB *shardStateHash = hash_create("Copy Shard State Hash", 128, &info, hashFlags);
return shardStateHash;
}
/*
* GetConnectionState finds existing CopyConnectionState for a connection in the
* provided hash. If not found, then a default structure is returned.
*/
static CopyConnectionState *
GetConnectionState(HTAB *connectionStateHash, MultiConnection *connection)
{
bool found = false;
int sock = PQsocket(connection->pgConn);
Assert(sock != -1);
CopyConnectionState *connectionState = (CopyConnectionState *) hash_search(
connectionStateHash, &sock,
HASH_ENTER,
&found);
if (!found)
{
connectionState->socket = sock;
connectionState->connection = connection;
connectionState->activePlacementState = NULL;
connectionState->bufferedPlacementCount = 0;
dlist_init(&connectionState->bufferedPlacementList);
}
return connectionState;
}
/*
* ConnectionStateList returns all CopyConnectionState structures in
* the given hash.
*/
static List *
ConnectionStateList(HTAB *connectionStateHash)
{
List *connectionStateList = NIL;
HASH_SEQ_STATUS status;
hash_seq_init(&status, connectionStateHash);
CopyConnectionState *connectionState = (CopyConnectionState *) hash_seq_search(
&status);
while (connectionState != NULL)
{
connectionStateList = lappend(connectionStateList, connectionState);
connectionState = (CopyConnectionState *) hash_seq_search(&status);
}
return connectionStateList;
}
/*
* ConnectionStateListToNode returns all CopyConnectionState structures in
* the given hash for a given hostname and port values.
*/
static List *
ConnectionStateListToNode(HTAB *connectionStateHash, const char *hostname, int32 port)
{
List *connectionStateList = NIL;
HASH_SEQ_STATUS status;
hash_seq_init(&status, connectionStateHash);
CopyConnectionState *connectionState =
(CopyConnectionState *) hash_seq_search(&status);
while (connectionState != NULL)
{
char *connectionHostname = connectionState->connection->hostname;
if (strncmp(connectionHostname, hostname, MAX_NODE_LENGTH) == 0 &&
connectionState->connection->port == port)
{
connectionStateList = lappend(connectionStateList, connectionState);
}
connectionState = (CopyConnectionState *) hash_seq_search(&status);
}
return connectionStateList;
}
/*
* GetShardState finds existing CopyShardState for a shard in the provided
* hash. If not found, then a new shard state is returned with all related
* CopyPlacementStates initialized.
*/
static CopyShardState *
GetShardState(uint64 shardId, HTAB *shardStateHash,
HTAB *connectionStateHash, bool *found, bool
shouldUseLocalCopy, CopyOutState copyOutState,
bool isColocatedIntermediateResult, bool isPublishable)
{
CopyShardState *shardState = (CopyShardState *) hash_search(shardStateHash, &shardId,
HASH_ENTER, found);
if (!*found)
{
InitializeCopyShardState(shardState, connectionStateHash,
shardId, shouldUseLocalCopy,
copyOutState, isColocatedIntermediateResult,
isPublishable);
}
return shardState;
}
/*
* InitializeCopyShardState initializes the given shardState. It finds all
* placements for the given shardId, assignes connections to them, and
* adds them to shardState->placementStateList.
*/
static void
InitializeCopyShardState(CopyShardState *shardState,
HTAB *connectionStateHash, uint64 shardId,
bool shouldUseLocalCopy,
CopyOutState copyOutState,
bool colocatedIntermediateResult,
bool isPublishable)
{
ListCell *placementCell = NULL;
int failedPlacementCount = 0;
bool hasRemoteCopy = false;
MemoryContext localContext =
AllocSetContextCreateInternal(CurrentMemoryContext,
"InitializeCopyShardState",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
/* release active placement list at the end of this function */
MemoryContext oldContext = MemoryContextSwitchTo(localContext);
List *activePlacementList = ActiveShardPlacementList(shardId);
MemoryContextSwitchTo(oldContext);
shardState->shardId = shardId;
shardState->placementStateList = NIL;
shardState->copyOutState = NULL;
shardState->containsLocalPlacement = ContainsLocalPlacement(shardId);
shardState->fileDest.fd = -1;
foreach(placementCell, activePlacementList)
{
ShardPlacement *placement = (ShardPlacement *) lfirst(placementCell);
if (shouldUseLocalCopy && placement->groupId == GetLocalGroupId())
{
shardState->copyOutState = (CopyOutState) palloc0(sizeof(*copyOutState));
CloneCopyOutStateForLocalCopy(copyOutState, shardState->copyOutState);
if (colocatedIntermediateResult)
{
LogLocalCopyToFileExecution(shardId);
}
else
{
LogLocalCopyToRelationExecution(shardId);
}
continue;
}
hasRemoteCopy = true;
MultiConnection *connection =
CopyGetPlacementConnection(connectionStateHash, placement,
colocatedIntermediateResult);
if (connection == NULL)
{
failedPlacementCount++;
continue;
}
CopyConnectionState *connectionState = GetConnectionState(connectionStateHash,
connection);
/*
* If this is the first time we are using this connection for copying a
* shard, send begin if necessary.
*/
if (connectionState->activePlacementState == NULL)
{
RemoteTransactionBeginIfNecessary(connection);
}
if (!isPublishable)
{
SetupReplicationOriginRemoteSession(connection);
}
CopyPlacementState *placementState = palloc0(sizeof(CopyPlacementState));
placementState->shardState = shardState;
placementState->data = makeStringInfo();
placementState->groupId = placement->groupId;
placementState->connectionState = connectionState;
/*
* We don't set connectionState->activePlacementState here even if it
* is NULL. Later in CitusSendTupleToPlacements() we set it at the
* same time as calling StartPlacementStateCopyCommand() so we actually
* know the COPY operation for the placement is ongoing.
*/
AddPlacementStateToCopyConnectionStateBuffer(connectionState, placementState);
shardState->placementStateList = lappend(shardState->placementStateList,
placementState);
}
/* if all placements failed, error out */
if (failedPlacementCount == list_length(activePlacementList))
{
ereport(ERROR, (errmsg("could not connect to any active placements")));
}
EnsureTaskExecutionAllowed(hasRemoteCopy);
/*
* We just error out and code execution should never reach to this
* point. This is the case for all tables.
*/
Assert(failedPlacementCount == 0);
MemoryContextReset(localContext);
}
/*
* CloneCopyOutStateForLocalCopy creates a shallow copy of the CopyOutState with a new
* fe_msgbuf. We keep a separate CopyOutState for every local shard placement, because
* in case of local copy we serialize and buffer incoming tuples into fe_msgbuf for each
* placement and the serialization functions take a CopyOutState as a parameter.
*/
static void
CloneCopyOutStateForLocalCopy(CopyOutState from, CopyOutState to)
{
to->attnumlist = from->attnumlist;
to->binary = from->binary;
to->copy_dest = from->copy_dest;
to->delim = from->delim;
to->file_encoding = from->file_encoding;
to->need_transcoding = from->need_transcoding;
to->null_print = from->null_print;
to->null_print_client = from->null_print_client;
to->rowcontext = from->rowcontext;
to->fe_msgbuf = makeStringInfo();
}
/*
* LogLocalCopyToRelationExecution logs that the copy will be done
* locally for the given shard.
*/
static void
LogLocalCopyToRelationExecution(uint64 shardId)
{
if (!(LogRemoteCommands || LogLocalCommands))
{
return;
}
ereport(NOTICE, (errmsg("executing the copy locally for shard %lu", shardId)));
}
/*
* LogLocalCopyToFileExecution logs that the copy will be done locally for
* a file colocated to the given shard.
*/
static void
LogLocalCopyToFileExecution(uint64 shardId)
{
if (!(LogRemoteCommands || LogLocalCommands))
{
return;
}
ereport(NOTICE, (errmsg("executing the copy locally for colocated file with "
"shard %lu", shardId)));
}
/*
* CopyGetPlacementConnection assigns a connection to the given placement. If
* a connection has already been assigned the placement in the current transaction
* then it reuses the connection. Otherwise, it requests a connection for placement.
*/
static MultiConnection *
CopyGetPlacementConnection(HTAB *connectionStateHash, ShardPlacement *placement,
bool colocatedIntermediateResult)
{
if (colocatedIntermediateResult)
{
/*
* Colocated intermediate results are just files and not required to use
* the same connections with their co-located shards. So, we are free to
* use any connection we can get.
*
* Also, the current connection re-use logic does not know how to handle
* intermediate results as the intermediate results always truncates the
* existing files. That's why we we use one connection per intermediate
* result.
*
* Also note that we are breaking the guarantees of citus.shared_pool_size
* as we cannot rely on optional connections.
*/
uint32 connectionFlagsForIntermediateResult = 0;
MultiConnection *connection =
GetNodeConnection(connectionFlagsForIntermediateResult, placement->nodeName,
placement->nodePort);
/*
* As noted above, we want each intermediate file to go over
* a separate connection.
*/
ClaimConnectionExclusively(connection);
/* and, we cannot afford to handle failures when anything goes wrong */
MarkRemoteTransactionCritical(connection);
return connection;
}
/*
* Determine whether the task has to be assigned to a particular connection
* due to a preceding access to the placement in the same transaction.
*/
ShardPlacementAccess *placementAccess = CreatePlacementAccess(placement,
PLACEMENT_ACCESS_DML);
uint32 connectionFlags = FOR_DML;
MultiConnection *connection =
GetConnectionIfPlacementAccessedInXact(connectionFlags,
list_make1(placementAccess), NULL);
if (connection != NULL)
{
/*
* Errors are supposed to cause immediate aborts (i.e. we don't
* want to/can't invalidate placements), mark the connection as
* critical so later errors cause failures.
*/
MarkRemoteTransactionCritical(connection);
return connection;
}
/*
* If we exceeded citus.max_adaptive_executor_pool_size, we should re-use the
* existing connections to multiplex multiple COPY commands on shards over a
* single connection.
*/
char *nodeName = placement->nodeName;
int nodePort = placement->nodePort;
List *copyConnectionStateList =
ConnectionStateListToNode(connectionStateHash, nodeName, nodePort);
if (HasReachedAdaptiveExecutorPoolSize(copyConnectionStateList))
{
/*
* If we've already reached the executor pool size, there should be at
* least one connection to any given node.
*
* Note that we don't need to mark the connection as critical, since the
* connection was already returned by this function before.
*/
connection = GetLeastUtilisedCopyConnection(copyConnectionStateList,
nodeName,
nodePort);
/*
* Make sure that the connection management remembers that Citus
* accesses this placement over the connection.
*/
AssignPlacementListToConnection(list_make1(placementAccess), connection);
return connection;
}
if (IsReservationPossible())
{
/*
* Enforce the requirements for adaptive connection management
* (a.k.a., throttle connections if citus.max_shared_pool_size
* reached).
*
* Given that we have done reservations per node, we do not ever
* need to pass WAIT_FOR_CONNECTION, we are sure that there is a
* connection either reserved for this backend or already established
* by the previous commands in the same transaction block.
*/
int adaptiveConnectionManagementFlag = OPTIONAL_CONNECTION;
connectionFlags |= adaptiveConnectionManagementFlag;
}
/*
* For placements that haven't been assigned a connection by a previous command
* in the current transaction, we use a separate connection per placement for
* hash-distributed tables in order to get the maximum performance.
*/
if (placement->partitionMethod == DISTRIBUTE_BY_HASH &&
MultiShardConnectionType != SEQUENTIAL_CONNECTION)
{
/*
* Claiming the connection exclusively (done below) would also have the
* effect of opening multiple connections, but claiming the connection
* exclusively prevents GetConnectionIfPlacementAccessedInXact from returning
* the connection if it is needed for a different shard placement.
*
* By setting the REQUIRE_CLEAN_CONNECTION flag we are guaranteed to get
* connection that will not be returned by GetConnectionIfPlacementAccessedInXact
* for the remainder of the COPY, hence it safe to claim the connection
* exclusively. Claiming a connection exclusively prevents it from being
* used in other distributed queries that happen during the COPY (e.g. if
* the copy logic calls a function to calculate a default value, and the
* function does a distributed query).
*/
connectionFlags |= REQUIRE_CLEAN_CONNECTION;
}
char *nodeUser = CurrentUserName();
connection = GetPlacementConnection(connectionFlags, placement, nodeUser);
if (connection == NULL)
{
if (list_length(copyConnectionStateList) > 0)
{
/*
* The connection manager throttled any new connections, so pick an existing
* connection with least utilization.
*
* Note that we don't need to mark the connection as critical, since the
* connection was already returned by this function before.
*/
connection =
GetLeastUtilisedCopyConnection(copyConnectionStateList, nodeName,
nodePort);
/*
* Make sure that the connection management remembers that Citus
* accesses this placement over the connection.
*/
AssignPlacementListToConnection(list_make1(placementAccess), connection);
}
else
{
/*
* For this COPY command, we have not established any connections
* and adaptive connection management throttled the new connection
* request. This could only happen if this COPY command is the
* second (or later) COPY command in a transaction block as the
* first COPY command always gets a connection per node thanks to
* the connection reservation.
*
* As we know that there has been at least one COPY command happened
* earlier, we need to find the connection to that node, and use it.
*/
connection =
ConnectionAvailableToNode(nodeName, nodePort, CurrentUserName(),
CurrentDatabaseName());
/*
* We do not expect this to happen, but still instead of an assert,
* we prefer explicit error message.
*/
if (connection == NULL)
{
ereport(ERROR, (errmsg("could not find an available connection"),
errhint("Set citus.max_shared_pool_size TO -1 to let "
"COPY command finish")));
}
}
return connection;
}
if (PQstatus(connection->pgConn) != CONNECTION_OK)
{
ReportConnectionError(connection, ERROR);
}
/*
* Errors are supposed to cause immediate aborts (i.e. we don't
* want to/can't invalidate placements), mark the connection as
* critical so later errors cause failures.
*/
MarkRemoteTransactionCritical(connection);
if (MultiShardConnectionType != SEQUENTIAL_CONNECTION)
{
ClaimConnectionExclusively(connection);
}
return connection;
}
/*
* HasReachedAdaptiveExecutorPoolSize returns true if the number of entries in input
* connection list has greater than or equal to citus.max_adaptive_executor_pool_size.
*/
static bool
HasReachedAdaptiveExecutorPoolSize(List *connectionStateList)
{
if (list_length(connectionStateList) >= MaxAdaptiveExecutorPoolSize)
{
/*
* We've not reached MaxAdaptiveExecutorPoolSize number of
* connections, so we're allowed to establish a new
* connection to the given node.
*/
return true;
}
return false;
}
/*
* GetLeastUtilisedCopyConnection returns a MultiConnection to the given node
* with the least number of placements assigned to it.
*
* It is assumed that there exists at least one connection to the node.
*/
static MultiConnection *
GetLeastUtilisedCopyConnection(List *connectionStateList, char *nodeName,
int nodePort)
{
MultiConnection *connection = NULL;
int minPlacementCount = PG_INT32_MAX;
ListCell *connectionStateCell = NULL;
/*
* We only pick the least utilised connection when some connection limits are
* reached such as max_shared_pool_size or max_adaptive_executor_pool_size.
*
* Therefore there should be some connections to choose from.
*/
Assert(list_length(connectionStateList) > 0);
foreach(connectionStateCell, connectionStateList)
{
CopyConnectionState *connectionState = lfirst(connectionStateCell);
int currentConnectionPlacementCount = connectionState->bufferedPlacementCount;
if (connectionState->activePlacementState != NULL)
{
currentConnectionPlacementCount++;
}
Assert(currentConnectionPlacementCount > 0);
if (currentConnectionPlacementCount < minPlacementCount)
{
minPlacementCount = currentConnectionPlacementCount;
connection = connectionState->connection;
}
}
return connection;
}
/*
* StartPlacementStateCopyCommand sends the COPY for the given placement. It also
* sends binary headers if this is a binary COPY.
*/
static void
StartPlacementStateCopyCommand(CopyPlacementState *placementState,
CopyStmt *copyStatement, CopyOutState copyOutState)
{
MultiConnection *connection = placementState->connectionState->connection;
uint64 shardId = placementState->shardState->shardId;
bool raiseInterrupts = true;
bool binaryCopy = copyOutState->binary;
StringInfo copyCommand = ConstructCopyStatement(copyStatement, shardId);
if (!SendRemoteCommand(connection, copyCommand->data))
{
ReportConnectionError(connection, ERROR);
}
PGresult *result = GetRemoteCommandResult(connection, raiseInterrupts);
if (PQresultStatus(result) != PGRES_COPY_IN)
{
ReportResultError(connection, result, ERROR);
}
PQclear(result);
if (binaryCopy)
{
SendCopyBinaryHeaders(copyOutState, shardId, list_make1(connection));
}
}
/*
* EndPlacementStateCopyCommand ends the COPY for the given placement. It also
* sends binary footers if this is a binary COPY.
*/
static void
EndPlacementStateCopyCommand(CopyPlacementState *placementState,
CopyOutState copyOutState)
{
MultiConnection *connection = placementState->connectionState->connection;
uint64 shardId = placementState->shardState->shardId;
bool binaryCopy = copyOutState->binary;
/* send footers and end copy command */
if (binaryCopy)
{
SendCopyBinaryFooters(copyOutState, shardId, list_make1(connection));
}
EndRemoteCopy(shardId, list_make1(connection));
}
/*
* UnclaimCopyConnections unclaims all the connections used for COPY.
*/
static void
UnclaimCopyConnections(List *connectionStateList)
{
ListCell *connectionStateCell = NULL;
foreach(connectionStateCell, connectionStateList)
{
CopyConnectionState *connectionState = lfirst(connectionStateCell);
UnclaimConnection(connectionState->connection);
}
}