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Avoid useless "x = ANY(ARRAY[])" test for empty partition list.

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This arises in practice if the partition only admits NULL values.

Jeevan Ladhe

Discussion: https://postgr.es/m/CAOgcT0OChrN--uuqH6wG6Z8+nxnCWJ+2Q-uhnK4KOANdRRxuAw@mail.gmail.com
This commit is contained in:
Tom Lane 2017-06-26 10:43:20 -04:00
parent 00c5e511b9
commit 5efccc1cb4
1 changed files with 37 additions and 18 deletions
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55
src/backend/catalog/partition.c
View file

@ -1311,6 +1311,12 @@ get_qual_for_list(PartitionKey key, PartitionBoundSpec *spec)
List *arrelems = NIL;
bool list_has_null = false;
/*
* Only single-column list partitioning is supported, so we are worried
* only about the partition key with index 0.
*/
Assert(key->partnatts == 1);
/* Construct Var or expression representing the partition column */
if (key->partattrs[0] != 0)
keyCol = (Expr *) makeVar(1,
@ -1333,20 +1339,28 @@ get_qual_for_list(PartitionKey key, PartitionBoundSpec *spec)
arrelems = lappend(arrelems, copyObject(val));
}
/* Construct an ArrayExpr for the non-null partition values */
arr = makeNode(ArrayExpr);
arr->array_typeid = !type_is_array(key->parttypid[0])
? get_array_type(key->parttypid[0])
: key->parttypid[0];
arr->array_collid = key->parttypcoll[0];
arr->element_typeid = key->parttypid[0];
arr->elements = arrelems;
arr->multidims = false;
arr->location = -1;
if (arrelems)
{
/* Construct an ArrayExpr for the non-null partition values */
arr = makeNode(ArrayExpr);
arr->array_typeid = !type_is_array(key->parttypid[0])
? get_array_type(key->parttypid[0])
: key->parttypid[0];
arr->array_collid = key->parttypcoll[0];
arr->element_typeid = key->parttypid[0];
arr->elements = arrelems;
arr->multidims = false;
arr->location = -1;
/* Generate the main expression, i.e., keyCol = ANY (arr) */
opexpr = make_partition_op_expr(key, 0, BTEqualStrategyNumber,
keyCol, (Expr *) arr);
/* Generate the main expression, i.e., keyCol = ANY (arr) */
opexpr = make_partition_op_expr(key, 0, BTEqualStrategyNumber,
keyCol, (Expr *) arr);
}
else
{
/* If there are no partition values, we don't need an = ANY expr */
opexpr = NULL;
}
if (!list_has_null)
{
@ -1361,7 +1375,7 @@ get_qual_for_list(PartitionKey key, PartitionBoundSpec *spec)
nulltest->argisrow = false;
nulltest->location = -1;
result = list_make2(nulltest, opexpr);
result = opexpr ? list_make2(nulltest, opexpr) : list_make1(nulltest);
}
else
{
@ -1369,16 +1383,21 @@ get_qual_for_list(PartitionKey key, PartitionBoundSpec *spec)
* Gin up a "col IS NULL" test that will be OR'd with the main
* expression.
*/
Expr *or;
nulltest = makeNode(NullTest);
nulltest->arg = keyCol;
nulltest->nulltesttype = IS_NULL;
nulltest->argisrow = false;
nulltest->location = -1;
or = makeBoolExpr(OR_EXPR, list_make2(nulltest, opexpr), -1);
result = list_make1(or);
if (opexpr)
{
Expr *or;
or = makeBoolExpr(OR_EXPR, list_make2(nulltest, opexpr), -1);
result = list_make1(or);
}
else
result = list_make1(nulltest);
}
return result;