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Improve space constraint exclusion datatype handling

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This patch adjusts the operator logic for valid space dimension
constraints to no longer look for an exact match on both sides
of the operator but instead allow mismatched datatypes.

Previously a constraint like `col = value` would require `col`
and `value` to have matching datatype with this change `col` and
`value` can be different datatype as long as they have equality
operator in btree family.

Mismatching datatype can happen commonly when using int8 columns
and comparing them with integer literals. Integer literals default
to int4 so the datatypes would not match unless special care has
been taken in writing the constraints and therefore the optimization
would never apply in those cases.
This commit is contained in:
Sven Klemm 2022-09-10 10:20:08 +02:00 committed by Sven Klemm
parent f27e627341
commit a26a5974dc
5 changed files with 336 additions and 19 deletions
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92
src/planner/space_constraint.c
View File

@ -12,6 +12,7 @@
#include <optimizer/optimizer.h>
#include <parser/parse_func.h>
#include <utils/fmgroids.h>
#include <utils/typcache.h>
#include "cache.h"
#include "dimension.h"
@ -42,6 +43,43 @@ get_space_dimension(Oid relid, Index varattno)
return NULL;
}
/*
* Check if this operator is compatible with the constraints on
* the space dimension. This is the equality operator between
* left and right in the btree operator family.
*/
static bool
is_valid_space_operator(Oid opno, Oid left, Oid right)
{
TypeCacheEntry *tce;
if (left == right)
{
/*
* When left and right match lookup_type_cache can
* directly return the equality operator saving us
* one roundtrip.
*/
tce = lookup_type_cache(left, TYPECACHE_EQ_OPR);
return tce && opno == tce->eq_opr;
}
else
{
/*
* The left and right type might not match when comparing
* different integer types eg comparing int2 or int8
* columns with integer literals which default to int4.
*/
tce = lookup_type_cache(left, TYPECACHE_BTREE_OPFAMILY);
if (!tce)
return false;
Oid eqop = get_opfamily_member(tce->btree_opf, left, right, BTEqualStrategyNumber);
return opno == eqop;
}
}
/*
* Valid constraints are: Var = Const
* Var has to refer to a space partitioning column
@ -54,9 +92,11 @@ is_valid_space_constraint(OpExpr *op, List *rtable)
return false;
Var *var = linitial_node(Var, op->args);
TypeCacheEntry *tce = lookup_type_cache(var->vartype, TYPECACHE_EQ_OPR);
if (var->varlevelsup != 0)
return false;
if (op->opno != tce->eq_opr || var->varlevelsup != 0)
Const *value = lsecond_node(Const, op->args);
if (!is_valid_space_operator(op->opno, var->vartype, value->consttype))
return false;
/*
@ -85,16 +125,12 @@ is_valid_scalar_space_constraint(ScalarArrayOpExpr *op, List *rtable)
if (!IsA(linitial(op->args), Var) || !IsA(lsecond(op->args), ArrayExpr))
return false;
ArrayExpr *arr = castNode(ArrayExpr, lsecond(op->args));
if (arr->multidims || !op->useOr)
return false;
Var *var = linitial_node(Var, op->args);
TypeCacheEntry *tce = lookup_type_cache(var->vartype, TYPECACHE_EQ_OPR);
if (var->vartype != arr->element_typeid || op->opno != tce->eq_opr)
ArrayExpr *arr = castNode(ArrayExpr, lsecond(op->args));
if (arr->multidims || !op->useOr || var->varlevelsup != 0)
return false;
if (var->varlevelsup != 0)
if (!is_valid_space_operator(op->opno, var->vartype, arr->element_typeid))
return false;
/*
@ -110,8 +146,23 @@ is_valid_scalar_space_constraint(ScalarArrayOpExpr *op, List *rtable)
ListCell *lc;
foreach (lc, arr->elements)
{
if (!IsA(lfirst(lc), Const) || lfirst_node(Const, lc)->consttype != var->vartype)
return false;
switch (nodeTag(lfirst(lc)))
{
case T_Const:
break;
case T_FuncExpr:
{
FuncExpr *element = lfirst_node(FuncExpr, lc);
if (element->funcformat != COERCE_IMPLICIT_CAST ||
!IsA(linitial(element->args), Const))
return false;
break;
}
default:
return false;
break;
}
}
return true;
}
@ -194,18 +245,21 @@ transform_scalar_space_constraint(PlannerInfo *root, List *rtable, ScalarArrayOp
foreach (lc, lsecond_node(ArrayExpr, op->args)->elements)
{
Const *value = lfirst_node(Const, lc);
Assert(IsA(lfirst(lc), Const) ||
(IsA(lfirst(lc), FuncExpr) &&
lfirst_node(FuncExpr, lc)->funcformat == COERCE_IMPLICIT_CAST));
/*
* We can skip NULL here as elements are ORed and partitioning dimensions
* have NOT NULL constraint.
*/
if (!value->constisnull)
{
List *args = list_make1(value);
partcall->args = args;
part_values = lappend(part_values,
castNode(Const, eval_const_expressions(root, (Node *) partcall)));
}
if (IsA(lfirst(lc), Const) && lfirst_node(Const, lc)->constisnull)
continue;
List *args = list_make1(lfirst(lc));
partcall->args = args;
part_values =
lappend(part_values, castNode(Const, eval_const_expressions(root, (Node *) partcall)));
}
/* build FuncExpr with column reference to use in constraint */
partcall->args = list_make1(copyObject(var));

85
tsl/test/shared/expected/space_constraint-12.out
View File

@ -54,6 +54,91 @@ QUERY PLAN
Filter: (device_id = ANY ('{1,3}'::integer[]))
(16 rows)
-- check mismatching datatypes
:PREFIX SELECT FROM metrics_space WHERE device_id = smallint '2' FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space
Filter: (device_id = '2'::smallint)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk
Index Cond: (device_id = '2'::smallint)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk
Index Cond: (device_id = '2'::smallint)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk
Index Cond: (device_id = '2'::smallint)
(10 rows)
:PREFIX SELECT FROM metrics_space WHERE device_id = int '2' FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space
Filter: (device_id = 2)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk
Index Cond: (device_id = 2)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk
Index Cond: (device_id = 2)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk
Index Cond: (device_id = 2)
(10 rows)
:PREFIX SELECT FROM metrics_space WHERE device_id = bigint '3' FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space
Filter: (device_id = '3'::bigint)
-> Seq Scan on _hyper_X_X_chunk
Filter: (device_id = '3'::bigint)
-> Seq Scan on _hyper_X_X_chunk
Filter: (device_id = '3'::bigint)
-> Seq Scan on _hyper_X_X_chunk
Filter: (device_id = '3'::bigint)
(10 rows)
:PREFIX SELECT FROM metrics_space WHERE device_id IN (smallint '1', smallint '1') FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk
Filter: (device_id = ANY ('{1,1}'::integer[]))
(10 rows)
:PREFIX SELECT FROM metrics_space WHERE device_id IN (int '1', int '1') FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk
Filter: (device_id = ANY ('{1,1}'::integer[]))
(10 rows)
:PREFIX SELECT FROM metrics_space WHERE device_id IN (bigint '1', bigint '1') FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space
Filter: (device_id = ANY ('{1,1}'::bigint[]))
-> Seq Scan on _hyper_X_X_chunk
Filter: (device_id = ANY ('{1,1}'::bigint[]))
-> Seq Scan on _hyper_X_X_chunk
Filter: (device_id = ANY ('{1,1}'::bigint[]))
-> Seq Scan on _hyper_X_X_chunk
Filter: (device_id = ANY ('{1,1}'::bigint[]))
(10 rows)
-- test valid variants we are optimizing
:PREFIX DELETE FROM metrics_space WHERE device_id = 1;
QUERY PLAN

85
tsl/test/shared/expected/space_constraint-13.out
View File

@ -54,6 +54,91 @@ QUERY PLAN
Filter: (device_id = ANY ('{1,3}'::integer[]))
(16 rows)
-- check mismatching datatypes
:PREFIX SELECT FROM metrics_space WHERE device_id = smallint '2' FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space metrics_space_1
Filter: (device_id = '2'::smallint)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk metrics_space_2
Index Cond: (device_id = '2'::smallint)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk metrics_space_3
Index Cond: (device_id = '2'::smallint)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk metrics_space_4
Index Cond: (device_id = '2'::smallint)
(10 rows)
:PREFIX SELECT FROM metrics_space WHERE device_id = int '2' FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space metrics_space_1
Filter: (device_id = 2)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk metrics_space_2
Index Cond: (device_id = 2)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk metrics_space_3
Index Cond: (device_id = 2)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk metrics_space_4
Index Cond: (device_id = 2)
(10 rows)
:PREFIX SELECT FROM metrics_space WHERE device_id = bigint '3' FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space metrics_space_1
Filter: (device_id = '3'::bigint)
-> Seq Scan on _hyper_X_X_chunk metrics_space_2
Filter: (device_id = '3'::bigint)
-> Seq Scan on _hyper_X_X_chunk metrics_space_3
Filter: (device_id = '3'::bigint)
-> Seq Scan on _hyper_X_X_chunk metrics_space_4
Filter: (device_id = '3'::bigint)
(10 rows)
:PREFIX SELECT FROM metrics_space WHERE device_id IN (smallint '1', smallint '1') FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space metrics_space_1
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_2
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_3
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_4
Filter: (device_id = ANY ('{1,1}'::integer[]))
(10 rows)
:PREFIX SELECT FROM metrics_space WHERE device_id IN (int '1', int '1') FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space metrics_space_1
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_2
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_3
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_4
Filter: (device_id = ANY ('{1,1}'::integer[]))
(10 rows)
:PREFIX SELECT FROM metrics_space WHERE device_id IN (bigint '1', bigint '1') FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space metrics_space_1
Filter: (device_id = ANY ('{1,1}'::bigint[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_2
Filter: (device_id = ANY ('{1,1}'::bigint[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_3
Filter: (device_id = ANY ('{1,1}'::bigint[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_4
Filter: (device_id = ANY ('{1,1}'::bigint[]))
(10 rows)
-- test valid variants we are optimizing
:PREFIX DELETE FROM metrics_space WHERE device_id = 1;
QUERY PLAN

85
tsl/test/shared/expected/space_constraint-14.out
View File

@ -54,6 +54,91 @@ QUERY PLAN
Filter: (device_id = ANY ('{1,3}'::integer[]))
(16 rows)
-- check mismatching datatypes
:PREFIX SELECT FROM metrics_space WHERE device_id = smallint '2' FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space metrics_space_1
Filter: (device_id = '2'::smallint)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk metrics_space_2
Index Cond: (device_id = '2'::smallint)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk metrics_space_3
Index Cond: (device_id = '2'::smallint)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk metrics_space_4
Index Cond: (device_id = '2'::smallint)
(10 rows)
:PREFIX SELECT FROM metrics_space WHERE device_id = int '2' FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space metrics_space_1
Filter: (device_id = 2)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk metrics_space_2
Index Cond: (device_id = 2)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk metrics_space_3
Index Cond: (device_id = 2)
-> Index Scan using _hyper_X_X_chunk_metrics_space_device_id_time_idx on _hyper_X_X_chunk metrics_space_4
Index Cond: (device_id = 2)
(10 rows)
:PREFIX SELECT FROM metrics_space WHERE device_id = bigint '3' FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space metrics_space_1
Filter: (device_id = '3'::bigint)
-> Seq Scan on _hyper_X_X_chunk metrics_space_2
Filter: (device_id = '3'::bigint)
-> Seq Scan on _hyper_X_X_chunk metrics_space_3
Filter: (device_id = '3'::bigint)
-> Seq Scan on _hyper_X_X_chunk metrics_space_4
Filter: (device_id = '3'::bigint)
(10 rows)
:PREFIX SELECT FROM metrics_space WHERE device_id IN (smallint '1', smallint '1') FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space metrics_space_1
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_2
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_3
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_4
Filter: (device_id = ANY ('{1,1}'::integer[]))
(10 rows)
:PREFIX SELECT FROM metrics_space WHERE device_id IN (int '1', int '1') FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space metrics_space_1
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_2
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_3
Filter: (device_id = ANY ('{1,1}'::integer[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_4
Filter: (device_id = ANY ('{1,1}'::integer[]))
(10 rows)
:PREFIX SELECT FROM metrics_space WHERE device_id IN (bigint '1', bigint '1') FOR UPDATE;
QUERY PLAN
LockRows
-> Append
-> Seq Scan on metrics_space metrics_space_1
Filter: (device_id = ANY ('{1,1}'::bigint[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_2
Filter: (device_id = ANY ('{1,1}'::bigint[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_3
Filter: (device_id = ANY ('{1,1}'::bigint[]))
-> Seq Scan on _hyper_X_X_chunk metrics_space_4
Filter: (device_id = ANY ('{1,1}'::bigint[]))
(10 rows)
-- test valid variants we are optimizing
:PREFIX DELETE FROM metrics_space WHERE device_id = 1;
QUERY PLAN

8
tsl/test/shared/sql/space_constraint.sql.in
View File

@ -14,6 +14,14 @@ SET timescaledb.current_timestamp_mock TO '1990-01-01';
:PREFIX SELECT FROM metrics_space WHERE device_id IN (1) FOR UPDATE;
:PREFIX SELECT FROM metrics_space WHERE device_id IN (1,3) FOR UPDATE;
-- check mismatching datatypes
:PREFIX SELECT FROM metrics_space WHERE device_id = smallint '2' FOR UPDATE;
:PREFIX SELECT FROM metrics_space WHERE device_id = int '2' FOR UPDATE;
:PREFIX SELECT FROM metrics_space WHERE device_id = bigint '3' FOR UPDATE;
:PREFIX SELECT FROM metrics_space WHERE device_id IN (smallint '1', smallint '1') FOR UPDATE;
:PREFIX SELECT FROM metrics_space WHERE device_id IN (int '1', int '1') FOR UPDATE;
:PREFIX SELECT FROM metrics_space WHERE device_id IN (bigint '1', bigint '1') FOR UPDATE;
-- test valid variants we are optimizing
:PREFIX DELETE FROM metrics_space WHERE device_id = 1;
:PREFIX DELETE FROM metrics_space WHERE device_id IN (1);