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Use a hash table to speed up NOT IN(values) 

Similar to 50e17ad28, which allowed hash tables to be used for IN clauses
with a set of constants, here we add the same feature for NOT IN clauses.

NOT IN evaluates the same as: WHERE a <> v1 AND a <> v2 AND a <> v3.
Obviously, if we're using a hash table we must be exactly equivalent to
that and return the same result taking into account that either side of
the condition could contain a NULL.  This requires a little bit of
special handling to make work with the hash table version.

When processing NOT IN, the ScalarArrayOpExpr's operator will be the <>
operator.  To be able to build and lookup a hash table we must use the
<>'s negator operator.  The planner checks if that exists and is hashable
and sets the relevant fields in ScalarArrayOpExpr to instruct the executor
to use hashing.

Author: David Rowley, James Coleman
Reviewed-by: James Coleman, Zhihong Yu
Discussion: https://postgr.es/m/CAApHDvoF1mum_FRk6D621edcB6KSHBi2+GAgWmioj5AhOu2vwQ@mail.gmail.com
This commit is contained in:
David Rowley 2021-07-07 16:29:17 +12:00
parent d854720df6
commit 29f45e299e
16 changed files with 242 additions and 29 deletions
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24
src/backend/executor/execExpr.c
View File

@ -1205,19 +1205,34 @@ ExecInitExprRec(Expr *node, ExprState *state,
AclResult aclresult;
FmgrInfo *hash_finfo;
FunctionCallInfo hash_fcinfo;
Oid cmpfuncid;
/*
* Select the correct comparison function. When we do hashed
* NOT IN clauses, the opfuncid will be the inequality
* comparison function and negfuncid will be set to equality.
* We need to use the equality function for hash probes.
*/
if (OidIsValid(opexpr->negfuncid))
{
Assert(OidIsValid(opexpr->hashfuncid));
cmpfuncid = opexpr->negfuncid;
}
else
cmpfuncid = opexpr->opfuncid;
Assert(list_length(opexpr->args) == 2);
scalararg = (Expr *) linitial(opexpr->args);
arrayarg = (Expr *) lsecond(opexpr->args);
/* Check permission to call function */
aclresult = pg_proc_aclcheck(opexpr->opfuncid,
aclresult = pg_proc_aclcheck(cmpfuncid,
GetUserId(),
ACL_EXECUTE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, OBJECT_FUNCTION,
get_func_name(opexpr->opfuncid));
InvokeFunctionExecuteHook(opexpr->opfuncid);
get_func_name(cmpfuncid));
InvokeFunctionExecuteHook(cmpfuncid);
if (OidIsValid(opexpr->hashfuncid))
{
@ -1233,7 +1248,7 @@ ExecInitExprRec(Expr *node, ExprState *state,
/* Set up the primary fmgr lookup information */
finfo = palloc0(sizeof(FmgrInfo));
fcinfo = palloc0(SizeForFunctionCallInfo(2));
fmgr_info(opexpr->opfuncid, finfo);
fmgr_info(cmpfuncid, finfo);
fmgr_info_set_expr((Node *) node, finfo);
InitFunctionCallInfoData(*fcinfo, finfo, 2,
opexpr->inputcollid, NULL, NULL);
@ -1274,6 +1289,7 @@ ExecInitExprRec(Expr *node, ExprState *state,
/* And perform the operation */
scratch.opcode = EEOP_HASHED_SCALARARRAYOP;
scratch.d.hashedscalararrayop.inclause = opexpr->useOr;
scratch.d.hashedscalararrayop.finfo = finfo;
scratch.d.hashedscalararrayop.fcinfo_data = fcinfo;
scratch.d.hashedscalararrayop.fn_addr = finfo->fn_addr;

17
src/backend/executor/execExprInterp.c
View File

@ -3493,6 +3493,7 @@ ExecEvalHashedScalarArrayOp(ExprState *state, ExprEvalStep *op, ExprContext *eco
{
ScalarArrayOpExprHashTable *elements_tab = op->d.hashedscalararrayop.elements_tab;
FunctionCallInfo fcinfo = op->d.hashedscalararrayop.fcinfo_data;
bool inclause = op->d.hashedscalararrayop.inclause;
bool strictfunc = op->d.hashedscalararrayop.finfo->fn_strict;
Datum scalar = fcinfo->args[0].value;
bool scalar_isnull = fcinfo->args[0].isnull;
@ -3596,7 +3597,12 @@ ExecEvalHashedScalarArrayOp(ExprState *state, ExprEvalStep *op, ExprContext *eco
/* Check the hash to see if we have a match. */
hashfound = NULL != saophash_lookup(elements_tab->hashtab, scalar);
result = BoolGetDatum(hashfound);
/* the result depends on if the clause is an IN or NOT IN clause */
if (inclause)
result = BoolGetDatum(hashfound); /* IN */
else
result = BoolGetDatum(!hashfound); /* NOT IN */
resultnull = false;
/*
@ -3605,7 +3611,7 @@ ExecEvalHashedScalarArrayOp(ExprState *state, ExprEvalStep *op, ExprContext *eco
* hashtable, but instead marked if we found any when building the table
* in has_nulls.
*/
if (!DatumGetBool(result) && op->d.hashedscalararrayop.has_nulls)
if (!hashfound && op->d.hashedscalararrayop.has_nulls)
{
if (strictfunc)
{
@ -3633,6 +3639,13 @@ ExecEvalHashedScalarArrayOp(ExprState *state, ExprEvalStep *op, ExprContext *eco
result = op->d.hashedscalararrayop.fn_addr(fcinfo);
resultnull = fcinfo->isnull;
/*
* Reverse the result for NOT IN clauses since the above function
* is the equality function and we need not-equals.
*/
if (!inclause)
result = !result;
}
}

1
src/backend/nodes/copyfuncs.c
View File

@ -1718,6 +1718,7 @@ _copyScalarArrayOpExpr(const ScalarArrayOpExpr *from)
COPY_SCALAR_FIELD(opno);
COPY_SCALAR_FIELD(opfuncid);
COPY_SCALAR_FIELD(hashfuncid);
COPY_SCALAR_FIELD(negfuncid);
COPY_SCALAR_FIELD(useOr);
COPY_SCALAR_FIELD(inputcollid);
COPY_NODE_FIELD(args);

6
src/backend/nodes/equalfuncs.c
View File

@ -414,6 +414,12 @@ _equalScalarArrayOpExpr(const ScalarArrayOpExpr *a, const ScalarArrayOpExpr *b)
b->hashfuncid != 0)
return false;
/* Likewise for the negfuncid */
if (a->negfuncid != b->negfuncid &&
a->negfuncid != 0 &&
b->negfuncid != 0)
return false;
COMPARE_SCALAR_FIELD(useOr);
COMPARE_SCALAR_FIELD(inputcollid);
COMPARE_NODE_FIELD(args);

1
src/backend/nodes/outfuncs.c
View File

@ -1311,6 +1311,7 @@ _outScalarArrayOpExpr(StringInfo str, const ScalarArrayOpExpr *node)
WRITE_OID_FIELD(opno);
WRITE_OID_FIELD(opfuncid);
WRITE_OID_FIELD(hashfuncid);
WRITE_OID_FIELD(negfuncid);
WRITE_BOOL_FIELD(useOr);
WRITE_OID_FIELD(inputcollid);
WRITE_NODE_FIELD(args);

1
src/backend/nodes/readfuncs.c
View File

@ -832,6 +832,7 @@ _readScalarArrayOpExpr(void)
READ_OID_FIELD(opno);
READ_OID_FIELD(opfuncid);
READ_OID_FIELD(hashfuncid);
READ_OID_FIELD(negfuncid);
READ_BOOL_FIELD(useOr);
READ_OID_FIELD(inputcollid);
READ_NODE_FIELD(args);

3
src/backend/optimizer/plan/setrefs.c
View File

@ -1687,6 +1687,9 @@ fix_expr_common(PlannerInfo *root, Node *node)
if (!OidIsValid(saop->hashfuncid))
record_plan_function_dependency(root, saop->hashfuncid);
if (!OidIsValid(saop->negfuncid))
record_plan_function_dependency(root, saop->negfuncid);
}
else if (IsA(node, Const))
{

1
src/backend/optimizer/prep/prepqual.c
View File

@ -128,6 +128,7 @@ negate_clause(Node *node)
newopexpr->opno = negator;
newopexpr->opfuncid = InvalidOid;
newopexpr->hashfuncid = InvalidOid;
newopexpr->negfuncid = InvalidOid;
newopexpr->useOr = !saopexpr->useOr;
newopexpr->inputcollid = saopexpr->inputcollid;
newopexpr->args = saopexpr->args;

80
src/backend/optimizer/util/clauses.c
View File

@ -2140,27 +2140,71 @@ convert_saop_to_hashed_saop_walker(Node *node, void *context)
Oid lefthashfunc;
Oid righthashfunc;
if (saop->useOr && arrayarg && IsA(arrayarg, Const) &&
!((Const *) arrayarg)->constisnull &&
get_op_hash_functions(saop->opno, &lefthashfunc, &righthashfunc) &&
lefthashfunc == righthashfunc)
if (arrayarg && IsA(arrayarg, Const) &&
!((Const *) arrayarg)->constisnull)
{
Datum arrdatum = ((Const *) arrayarg)->constvalue;
ArrayType *arr = (ArrayType *) DatumGetPointer(arrdatum);
int nitems;
/*
* Only fill in the hash functions if the array looks large enough
* for it to be worth hashing instead of doing a linear search.
*/
nitems = ArrayGetNItems(ARR_NDIM(arr), ARR_DIMS(arr));
if (nitems >= MIN_ARRAY_SIZE_FOR_HASHED_SAOP)
if (saop->useOr)
{
/* Looks good. Fill in the hash functions */
saop->hashfuncid = lefthashfunc;
if (get_op_hash_functions(saop->opno, &lefthashfunc, &righthashfunc) &&
lefthashfunc == righthashfunc)
{
Datum arrdatum = ((Const *) arrayarg)->constvalue;
ArrayType *arr = (ArrayType *) DatumGetPointer(arrdatum);
int nitems;
/*
* Only fill in the hash functions if the array looks
* large enough for it to be worth hashing instead of
* doing a linear search.
*/
nitems = ArrayGetNItems(ARR_NDIM(arr), ARR_DIMS(arr));
if (nitems >= MIN_ARRAY_SIZE_FOR_HASHED_SAOP)
{
/* Looks good. Fill in the hash functions */
saop->hashfuncid = lefthashfunc;
}
return true;
}
}
else /* !saop->useOr */
{
Oid negator = get_negator(saop->opno);
/*
* Check if this is a NOT IN using an operator whose negator
* is hashable. If so we can still build a hash table and
* just ensure the lookup items are not in the hash table.
*/
if (OidIsValid(negator) &&
get_op_hash_functions(negator, &lefthashfunc, &righthashfunc) &&
lefthashfunc == righthashfunc)
{
Datum arrdatum = ((Const *) arrayarg)->constvalue;
ArrayType *arr = (ArrayType *) DatumGetPointer(arrdatum);
int nitems;
/*
* Only fill in the hash functions if the array looks
* large enough for it to be worth hashing instead of
* doing a linear search.
*/
nitems = ArrayGetNItems(ARR_NDIM(arr), ARR_DIMS(arr));
if (nitems >= MIN_ARRAY_SIZE_FOR_HASHED_SAOP)
{
/* Looks good. Fill in the hash functions */
saop->hashfuncid = lefthashfunc;
/*
* Also set the negfuncid. The executor will need
* that to perform hashtable lookups.
*/
saop->negfuncid = get_opcode(negator);
}
return true;
}
}
return true;
}
}

1
src/backend/parser/parse_oper.c
View File

@ -895,6 +895,7 @@ make_scalar_array_op(ParseState *pstate, List *opname,
result->opno = oprid(tup);
result->opfuncid = opform->oprcode;
result->hashfuncid = InvalidOid;
result->negfuncid = InvalidOid;
result->useOr = useOr;
/* inputcollid will be set by parse_collate.c */
result->args = args;

1
src/backend/partitioning/partbounds.c
View File

@ -3878,6 +3878,7 @@ make_partition_op_expr(PartitionKey key, int keynum,
saopexpr->opno = operoid;
saopexpr->opfuncid = get_opcode(operoid);
saopexpr->hashfuncid = InvalidOid;
saopexpr->negfuncid = InvalidOid;
saopexpr->useOr = true;
saopexpr->inputcollid = key->partcollation[keynum];
saopexpr->args = list_make2(arg1, arrexpr);

2
src/include/catalog/catversion.h
View File

@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 202106151
#define CATALOG_VERSION_NO 202107071
#endif

1
src/include/executor/execExpr.h
View File

@ -574,6 +574,7 @@ typedef struct ExprEvalStep
struct
{
bool has_nulls;
bool inclause; /* true for IN and false for NOT IN */
struct ScalarArrayOpExprHashTable *elements_tab;
FmgrInfo *finfo; /* function's lookup data */
FunctionCallInfo fcinfo_data; /* arguments etc */

18
src/include/nodes/primnodes.h
View File

@ -580,10 +580,18 @@ typedef OpExpr NullIfExpr;
* the result type (or the collation) because it must be boolean.
*
* A ScalarArrayOpExpr with a valid hashfuncid is evaluated during execution
* by building a hash table containing the Const values from the rhs arg.
* This table is probed during expression evaluation. Only useOr=true
* ScalarArrayOpExpr with Const arrays on the rhs can have the hashfuncid
* field set. See convert_saop_to_hashed_saop().
* by building a hash table containing the Const values from the RHS arg.
* This table is probed during expression evaluation. The planner will set
* hashfuncid to the hash function which must be used to build and probe the
* hash table. The executor determines if it should use hash-based checks or
* the more traditional means based on if the hashfuncid is set or not.
*
* When performing hashed NOT IN, the negfuncid will also be set to the
* equality function which the hash table must use to build and probe the hash
* table. opno and opfuncid will remain set to the <> operator and its
* corresponding function and won't be used during execution. For
* non-hashtable based NOT INs, negfuncid will be set to InvalidOid. See
* convert_saop_to_hashed_saop().
*/
typedef struct ScalarArrayOpExpr
{
@ -591,6 +599,8 @@ typedef struct ScalarArrayOpExpr
Oid opno; /* PG_OPERATOR OID of the operator */
Oid opfuncid; /* PG_PROC OID of comparison function */
Oid hashfuncid; /* PG_PROC OID of hash func or InvalidOid */
Oid negfuncid; /* PG_PROC OID of negator of opfuncid function
* or InvalidOid. See above */
bool useOr; /* true for ANY, false for ALL */
Oid inputcollid; /* OID of collation that operator should use */
List *args; /* the scalar and array operands */

84
src/test/regress/expected/expressions.out
View File

@ -216,6 +216,55 @@ select return_text_input('a') in ('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', '
t
(1 row)
-- NOT IN
select return_int_input(1) not in (10, 9, 2, 8, 3, 7, 4, 6, 5, 1);
?column?
----------
f
(1 row)
select return_int_input(1) not in (10, 9, 2, 8, 3, 7, 4, 6, 5, 0);
?column?
----------
t
(1 row)
select return_int_input(1) not in (10, 9, 2, 8, 3, 7, 4, 6, 5, 2, null);
?column?
----------
(1 row)
select return_int_input(1) not in (10, 9, 2, 8, 3, 7, 4, 6, 5, 1, null);
?column?
----------
f
(1 row)
select return_int_input(1) not in (null, null, null, null, null, null, null, null, null, null, null);
?column?
----------
(1 row)
select return_int_input(null::int) not in (10, 9, 2, 8, 3, 7, 4, 6, 5, 1);
?column?
----------
(1 row)
select return_int_input(null::int) not in (10, 9, 2, 8, 3, 7, 4, 6, 5, null);
?column?
----------
(1 row)
select return_text_input('a') not in ('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j');
?column?
----------
f
(1 row)
rollback;
-- Test with non-strict equality function.
-- We need to create our own type for this.
@ -242,6 +291,11 @@ begin
end if;
end;
$$ language plpgsql immutable;
create function myintne(myint, myint) returns bool as $$
begin
return not myinteq($1, $2);
end;
$$ language plpgsql immutable;
create operator = (
leftarg = myint,
rightarg = myint,
@ -252,6 +306,16 @@ create operator = (
join = eqjoinsel,
merges
);
create operator <> (
leftarg = myint,
rightarg = myint,
commutator = <>,
negator = =,
procedure = myintne,
restrict = eqsel,
join = eqjoinsel,
merges
);
create operator class myint_ops
default for type myint using hash as
operator 1 = (myint, myint),
@ -266,6 +330,16 @@ select * from inttest where a in (1::myint,2::myint,3::myint,4::myint,5::myint,6
(2 rows)
select * from inttest where a not in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint, null);
a
---
(0 rows)
select * from inttest where a not in (0::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint, null);
a
---
(0 rows)
-- ensure the result matched with the non-hashed version. We simply remove
-- some array elements so that we don't reach the hashing threshold.
select * from inttest where a in (1::myint,2::myint,3::myint,4::myint,5::myint, null);
@ -275,4 +349,14 @@ select * from inttest where a in (1::myint,2::myint,3::myint,4::myint,5::myint,
(2 rows)
select * from inttest where a not in (1::myint,2::myint,3::myint,4::myint,5::myint, null);
a
---
(0 rows)
select * from inttest where a not in (0::myint,2::myint,3::myint,4::myint,5::myint, null);
a
---
(0 rows)
rollback;

30
src/test/regress/sql/expressions.sql
View File

@ -93,6 +93,15 @@ select return_int_input(1) in (10, 9, 2, 8, 3, 7, 4, 6, 5, 1, null);
select return_int_input(null::int) in (10, 9, 2, 8, 3, 7, 4, 6, 5, 1);
select return_int_input(null::int) in (10, 9, 2, 8, 3, 7, 4, 6, 5, null);
select return_text_input('a') in ('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j');
-- NOT IN
select return_int_input(1) not in (10, 9, 2, 8, 3, 7, 4, 6, 5, 1);
select return_int_input(1) not in (10, 9, 2, 8, 3, 7, 4, 6, 5, 0);
select return_int_input(1) not in (10, 9, 2, 8, 3, 7, 4, 6, 5, 2, null);
select return_int_input(1) not in (10, 9, 2, 8, 3, 7, 4, 6, 5, 1, null);
select return_int_input(1) not in (null, null, null, null, null, null, null, null, null, null, null);
select return_int_input(null::int) not in (10, 9, 2, 8, 3, 7, 4, 6, 5, 1);
select return_int_input(null::int) not in (10, 9, 2, 8, 3, 7, 4, 6, 5, null);
select return_text_input('a') not in ('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j');
rollback;
@ -124,6 +133,12 @@ begin
end;
$$ language plpgsql immutable;
create function myintne(myint, myint) returns bool as $$
begin
return not myinteq($1, $2);
end;
$$ language plpgsql immutable;
create operator = (
leftarg = myint,
rightarg = myint,
@ -135,6 +150,17 @@ create operator = (
merges
);
create operator <> (
leftarg = myint,
rightarg = myint,
commutator = <>,
negator = =,
procedure = myintne,
restrict = eqsel,
join = eqjoinsel,
merges
);
create operator class myint_ops
default for type myint using hash as
operator 1 = (myint, myint),
@ -145,8 +171,12 @@ insert into inttest values(1::myint),(null);
-- try an array with enough elements to cause hashing
select * from inttest where a in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint, null);
select * from inttest where a not in (1::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint, null);
select * from inttest where a not in (0::myint,2::myint,3::myint,4::myint,5::myint,6::myint,7::myint,8::myint,9::myint, null);
-- ensure the result matched with the non-hashed version. We simply remove
-- some array elements so that we don't reach the hashing threshold.
select * from inttest where a in (1::myint,2::myint,3::myint,4::myint,5::myint, null);
select * from inttest where a not in (1::myint,2::myint,3::myint,4::myint,5::myint, null);
select * from inttest where a not in (0::myint,2::myint,3::myint,4::myint,5::myint, null);
rollback;