external
/
citus
mirror of https://github.com/citusdata/citus.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Skip shard pruning when possible 

We're already traversing the queryTree and finding the distribution
key value, so pass it to the later stages of the planning.
pull/3332/head
Onder Kalaci 2019-12-19 11:20:59 +01:00 committed by Jelte Fennema
parent ca293116fa
commit 7f3ab7892d
6 changed files with 72 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
src/backend/distributed/planner/distributed_planner.c
View File

@ -129,6 +129,7 @@ distributed_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
List *rangeTableList = ExtractRangeTableEntryList(parse);
int rteIdCounter = 1;
bool fastPathRouterQuery = false;
Const *distributionKeyValue = NULL;
if (cursorOptions & CURSOR_OPT_FORCE_DISTRIBUTED)
{
@ -154,7 +155,7 @@ distributed_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
needsDistributedPlanning = ListContainsDistributedTableRTE(rangeTableList);
if (needsDistributedPlanning)
{
fastPathRouterQuery = FastPathRouterQuery(parse);
fastPathRouterQuery = FastPathRouterQuery(parse, &distributionKeyValue);
}
}
}
@ -224,6 +225,8 @@ distributed_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
{
plannerRestrictionContext->fastPathRestrictionContext->fastPathRouterQuery =
true;
plannerRestrictionContext->fastPathRestrictionContext->distributionKeyValue =
distributionKeyValue;
result = FastPathPlanner(originalQuery, parse, boundParams);
}

38
src/backend/distributed/planner/fast_path_router_planner.c
View File

@ -58,8 +58,10 @@
bool EnableFastPathRouterPlanner = true;
static bool ColumnAppearsMultipleTimes(Node *quals, Var *distributionKey);
static bool ConjunctionContainsColumnFilter(Node *node, Var *column);
static bool DistKeyInSimpleOpExpression(Expr *clause, Var *distColumn);
static bool ConjunctionContainsColumnFilter(Node *node, Var *column,
Const **distributionKeyValue);
static bool DistKeyInSimpleOpExpression(Expr *clause, Var *distColumn,
Const **distributionKeyValue);
/*
@ -122,7 +124,9 @@ GeneratePlaceHolderPlannedStmt(Query *parse)
SeqScan *seqScanNode = makeNode(SeqScan);
Plan *plan = &seqScanNode->plan;
AssertArg(FastPathRouterQuery(parse));
Const *distKey PG_USED_FOR_ASSERTS_ONLY = NULL;
AssertArg(FastPathRouterQuery(parse, &distKey));
/* there is only a single relation rte */
seqScanNode->scanrelid = 1;
@ -162,11 +166,12 @@ GeneratePlaceHolderPlannedStmt(Query *parse)
* and it should be ANDed with any other filters. Also, the distribution
* key should only exists once in the WHERE clause. So basically,
* SELECT ... FROM dist_table WHERE dist_key = X
* If the filter is a const, distributionKeyValue is set
* - All INSERT statements (including multi-row INSERTs) as long as the commands
* don't have any sublinks/CTEs etc
*/
bool
FastPathRouterQuery(Query *query)
FastPathRouterQuery(Query *query, Const **distributionKeyValue)
{
FromExpr *joinTree = query->jointree;
Node *quals = NULL;
@ -254,7 +259,7 @@ FastPathRouterQuery(Query *query)
* This is to simplify both of the individual checks and omit various edge cases
* that might arise with multiple distribution keys in the quals.
*/
if (ConjunctionContainsColumnFilter(quals, distributionKey) &&
if (ConjunctionContainsColumnFilter(quals, distributionKey, distributionKeyValue) &&
!ColumnAppearsMultipleTimes(quals, distributionKey))
{
return true;
@ -298,9 +303,11 @@ ColumnAppearsMultipleTimes(Node *quals, Var *distributionKey)
* ConjunctionContainsColumnFilter returns true if the query contains an exact
* match (equal) expression on the provided column. The function returns true only
* if the match expression has an AND relation with the rest of the expression tree.
*
* If the conjuction contains column filter which is const, distributionKeyValue is set.
*/
static bool
ConjunctionContainsColumnFilter(Node *node, Var *column)
ConjunctionContainsColumnFilter(Node *node, Var *column, Const **distributionKeyValue)
{
if (node == NULL)
{
@ -311,7 +318,7 @@ ConjunctionContainsColumnFilter(Node *node, Var *column)
{
OpExpr *opExpr = (OpExpr *) node;
bool distKeyInSimpleOpExpression =
DistKeyInSimpleOpExpression((Expr *) opExpr, column);
DistKeyInSimpleOpExpression((Expr *) opExpr, column, distributionKeyValue);
if (!distKeyInSimpleOpExpression)
{
@ -342,7 +349,8 @@ ConjunctionContainsColumnFilter(Node *node, Var *column)
{
Node *argumentNode = (Node *) lfirst(argumentCell);
if (ConjunctionContainsColumnFilter(argumentNode, column))
if (ConjunctionContainsColumnFilter(argumentNode, column,
distributionKeyValue))
{
return true;
}
@ -357,9 +365,11 @@ ConjunctionContainsColumnFilter(Node *node, Var *column)
* DistKeyInSimpleOpExpression checks whether given expression is a simple operator
* expression with either (dist_key = param) or (dist_key = const). Note that the
* operands could be in the reverse order as well.
*
* When a const is found, distributionKeyValue is set.
*/
static bool
DistKeyInSimpleOpExpression(Expr *clause, Var *distColumn)
DistKeyInSimpleOpExpression(Expr *clause, Var *distColumn, Const **distributionKeyValue)
{
Node *leftOperand = NULL;
Node *rightOperand = NULL;
@ -420,6 +430,14 @@ DistKeyInSimpleOpExpression(Expr *clause, Var *distColumn)
/* at this point we should have the columnInExpr */
Assert(columnInExpr);
bool distColumnExists = equal(distColumn, columnInExpr);
if (distColumnExists && constantClause != NULL &&
distColumn->vartype == constantClause->consttype &&
*distributionKeyValue == NULL)
{
/* if the vartypes do not match, let shard pruning handle it later */
*distributionKeyValue = copyObject(constantClause);
}
return equal(distColumn, columnInExpr);
return distColumnExists;
}

31
src/backend/distributed/planner/multi_router_planner.c
View File

@ -1617,8 +1617,9 @@ ExtractFirstDistributedTableId(Query *query)
List *rangeTableList = query->rtable;
ListCell *rangeTableCell = NULL;
Oid distributedTableId = InvalidOid;
Const *distKey PG_USED_FOR_ASSERTS_ONLY = NULL;
Assert(IsModifyCommand(query) || FastPathRouterQuery(query));
Assert(IsModifyCommand(query) || FastPathRouterQuery(query, &distKey));
foreach(rangeTableCell, rangeTableList)
{
@ -2026,9 +2027,32 @@ PlanRouterQuery(Query *originalQuery,
*/
if (fastPathRouterQuery)
{
List *shardIntervalList =
List *shardIntervalList = NIL;
Const *distributionKeyValue =
plannerRestrictionContext->fastPathRestrictionContext->distributionKeyValue;
if (distributionKeyValue)
{
Oid relationId = ExtractFirstDistributedTableId(originalQuery);
DistTableCacheEntry *cache = DistributedTableCacheEntry(relationId);
ShardInterval *shardInterval =
FindShardInterval(distributionKeyValue->constvalue, cache);
shardIntervalList = list_make1(shardInterval);
if (partitionValueConst != NULL)
{
/* set the outgoing partition column value if requested */
*partitionValueConst = distributionKeyValue;
}
}
else
{
shardIntervalList =
TargetShardIntervalForFastPathQuery(originalQuery, partitionValueConst,
&isMultiShardQuery);
}
/*
* This could only happen when there is a parameter on the distribution key.
@ -2263,7 +2287,8 @@ TargetShardIntervalForFastPathQuery(Query *query, Const **partitionValueConst,
&queryPartitionValueConst);
/* we're only expecting single shard from a single table */
Assert(FastPathRouterQuery(query));
Const *distKey PG_USED_FOR_ASSERTS_ONLY = NULL;
Assert(FastPathRouterQuery(query, &distKey));
if (list_length(prunedShardIntervalList) > 1)
{

8
src/include/distributed/distributed_planner.h
View File

@ -88,6 +88,14 @@ typedef struct JoinRestriction
typedef struct FastPathRestrictionContext
{
bool fastPathRouterQuery;
/*
* While calculating fastPathRouterQuery, we could sometimes be
* able to extract the distribution key value as well (such as when
* there are no prepared statements). Could be NULL when the distribution
* key contains parameter, so check for it before using.
*/
Const *distributionKeyValue;
}FastPathRestrictionContext;
typedef struct PlannerRestrictionContext

2
src/include/distributed/multi_router_planner.h
View File

@ -78,6 +78,6 @@ extern List * WorkersContainingAllShards(List *prunedShardIntervalsList);
extern PlannedStmt * FastPathPlanner(Query *originalQuery, Query *parse, ParamListInfo
boundParams);
extern bool FastPathRouterQuery(Query *query);
extern bool FastPathRouterQuery(Query *query, Const **distributionKeyValue);
#endif /* MULTI_ROUTER_PLANNER_H */

1
src/test/regress/expected/fast_path_router_modify.out
View File

@ -61,6 +61,7 @@ DELETE FROM modify_fast_path WHERE key = 1 and FALSE;
DEBUG: Distributed planning for a fast-path router query
DEBUG: Creating router plan
DEBUG: Plan is router executable
DETAIL: distribution column value: 1
-- UPDATE may include complex target entries
UPDATE modify_fast_path SET value_1 = value_1 + 12 * value_1 WHERE key = 1;
DEBUG: Distributed planning for a fast-path router query