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Convert router executor to use new connection API 

This commit slightly changes router executor to use new connection API
for getting the connections.
pull/1053/head
Onder Kalaci 2016-12-19 15:28:19 +02:00
parent 4ea4bfbf45
commit c9e569bf3d
1 changed files with 49 additions and 25 deletions
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74
src/backend/distributed/executor/multi_router_executor.c
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@ -106,8 +106,9 @@ static bool RequiresConsistentSnapshot(Task *task);
static uint64 ReturnRowsFromTuplestore(uint64 tupleCount, TupleDesc tupleDescriptor,
DestReceiver *destination,
Tuplestorestate *tupleStore);
static PGconn * GetConnectionForPlacement(ShardPlacement *placement,
bool isModificationQuery);
static void ManageShardIdParticipantForTransactionBlock(uint64 shardId,
MultiConnection *connection,
bool isModificationQuery);
static void PurgeConnectionForPlacement(PGconn *connection, ShardPlacement *placement);
static void RemoveXactConnection(PGconn *connection);
static void ExtractParametersFromParamListInfo(ParamListInfo paramListInfo,
@ -765,15 +766,24 @@ ExecuteSingleTask(QueryDesc *queryDesc, Task *task,
bool queryOK = false;
bool failOnError = false;
int64 currentAffectedTupleCount = 0;
PGconn *connection = GetConnectionForPlacement(taskPlacement,
isModificationQuery);
PGconn *connection = GetOrEstablishConnection(taskPlacement->nodeName,
taskPlacement->nodePort);
MultiConnection *multiConnection = NULL;
if (connection == NULL)
{
failedPlacementList = lappend(failedPlacementList, taskPlacement);
continue;
}
multiConnection = GetConnectionFromPGconn(connection);
ManageShardIdParticipantForTransactionBlock(task->anchorShardId, multiConnection,
isModificationQuery);
connection = multiConnection->pgConn;
queryOK = SendQueryInSingleRowMode(connection, queryString, paramListInfo);
if (!queryOK)
{
@ -1156,34 +1166,50 @@ ReturnRowsFromTuplestore(uint64 tupleCount, TupleDesc tupleDescriptor,
/*
* GetConnectionForPlacement is the main entry point for acquiring a connection
* within the router executor. By using placements (rather than node names and
* ports) to identify connections, the router executor can keep track of shards
* used by multi-statement transactions and error out if a transaction tries
* to reach a new node altogether). In the single-statement commands context,
* GetConnectionForPlacement simply falls through to GetOrEstablishConnection.
* ManageShardIdParticipantForTransactionBlock for the given shardId and connection
* does the following:
*
* i) if not in a transaction block, simply do nothing and return
* ii) if the query is not modification and no modifications has happened
* so far, do nothing
* iii) if the node has already participated in a modification and the current
* query is also a modification query, record the shard id participant
* iv) if the query is attempting to expand the set of affected worker nodes
* within the transaction block, error out
*/
static PGconn *
GetConnectionForPlacement(ShardPlacement *placement, bool isModificationQuery)
static void
ManageShardIdParticipantForTransactionBlock(uint64 shardId, MultiConnection *connection,
bool isModificationQuery)
{
NodeConnectionKey participantKey;
NodeConnectionEntry *participantEntry = NULL;
bool entryFound = false;
/* if not in a transaction, fall through to connection cache */
if (xactParticipantHash == NULL)
/* we only care about sessions that are in a transaction */
if (!IsTransactionBlock())
{
PGconn *connection = GetOrEstablishConnection(placement->nodeName,
placement->nodePort);
return connection;
return;
}
Assert(IsTransactionBlock());
/* if a SELECT query executed before any modifications do not need to proceed */
if (xactParticipantHash == NULL && !isModificationQuery)
{
return;
}
else if (xactParticipantHash == NULL && isModificationQuery)
{
/*
* We should never get here given that modification queries
* within a transaction should have already created the hash.
* But still an error message is better than an assertion.
*/
ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("no transaction participant found")));
}
MemSet(&participantKey, 0, sizeof(participantKey));
strlcpy(participantKey.nodeName, placement->nodeName, MAX_NODE_LENGTH + 1);
participantKey.nodePort = placement->nodePort;
strlcpy(participantKey.nodeName, connection->hostname, MAX_NODE_LENGTH + 1);
participantKey.nodePort = connection->port;
participantEntry = hash_search(xactParticipantHash, &participantKey, HASH_FIND,
&entryFound);
@ -1192,16 +1218,14 @@ GetConnectionForPlacement(ShardPlacement *placement, bool isModificationQuery)
{
if (isModificationQuery)
{
RecordShardIdParticipant(placement->shardId, participantEntry);
RecordShardIdParticipant(shardId, participantEntry);
}
return participantEntry->connection->pgConn;
}
else
{
ereport(ERROR, (errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST),
errmsg("no transaction participant matches %s:%d",
placement->nodeName, placement->nodePort),
connection->hostname, connection->port),
errdetail("Transactions which modify distributed tables may only "
"target nodes affected by the modification command "
"which began the transaction.")));