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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
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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;
}

35
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 =
TargetShardIntervalForFastPathQuery(originalQuery, partitionValueConst,
&isMultiShardQuery);
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