diff options
Diffstat (limited to 'src/backend/executor/nodeSubplan.c')
| -rw-r--r-- | src/backend/executor/nodeSubplan.c | 53 |
1 files changed, 51 insertions, 2 deletions
diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c index 9f6e45bcb0b..1cd0988bb49 100644 --- a/src/backend/executor/nodeSubplan.c +++ b/src/backend/executor/nodeSubplan.c @@ -525,7 +525,7 @@ buildSubPlanHash(SubPlanState *node, ExprContext *econtext) node->tab_hash_funcs, node->tab_collations, nbuckets, - 0, + 0, /* no additional data */ node->planstate->state->es_query_cxt, node->tuplesContext, innerecontext->ecxt_per_tuple_memory, @@ -554,7 +554,7 @@ buildSubPlanHash(SubPlanState *node, ExprContext *econtext) node->tab_hash_funcs, node->tab_collations, nbuckets, - 0, + 0, /* no additional data */ node->planstate->state->es_query_cxt, node->tuplesContext, innerecontext->ecxt_per_tuple_memory, @@ -636,6 +636,55 @@ buildSubPlanHash(SubPlanState *node, ExprContext *econtext) MemoryContextSwitchTo(oldcontext); } +/* Planner support routine to estimate space needed for hash table(s) */ +Size +EstimateSubplanHashTableSpace(double nentries, + Size tupleWidth, + bool unknownEqFalse) +{ + Size tab1space, + tab2space; + + /* Estimate size of main hashtable */ + tab1space = EstimateTupleHashTableSpace(nentries, + tupleWidth, + 0 /* no additional data */ ); + + /* Give up if that's already too big */ + if (tab1space >= SIZE_MAX) + return tab1space; + + /* Done if we don't need a hashnulls table */ + if (unknownEqFalse) + return tab1space; + + /* + * Adjust the rowcount estimate in the same way that buildSubPlanHash + * will, except that we don't bother with the special case for a single + * hash column. (We skip that detail because it'd be notationally painful + * for our caller to provide the column count, and this table has + * relatively little impact on the total estimate anyway.) + */ + nentries /= 16; + if (nentries < 1) + nentries = 1; + + /* + * It might be sane to also reduce the tupleWidth, but on the other hand + * we are not accounting for the space taken by the tuples' null bitmaps. + * Leave it alone for now. + */ + tab2space = EstimateTupleHashTableSpace(nentries, + tupleWidth, + 0 /* no additional data */ ); + + /* Guard against overflow */ + if (tab2space >= SIZE_MAX - tab1space) + return SIZE_MAX; + + return tab1space + tab2space; +} + /* * execTuplesUnequal * Return true if two tuples are definitely unequal in the indicated |