While working on 4c2369ac5, I noticed there's close to as much code to
disallow BooleanTests in the form of "IS UNKNOWN" and "IS NOT UNKNOWN"
in partition pruning as it would take to allow pruning to work for
these.
The attached makes it work.
David
From b9f3ff909652c96f1f0dced9e1165ffa8c93c7f1 Mon Sep 17 00:00:00 2001
From: David Rowley <dgrow...@gmail.com>
Date: Tue, 20 Feb 2024 14:56:49 +1300
Subject: [PATCH v1] Support partition pruning on boolcol IS [NOT] UNKNOWN
While working on 4c2369ac5, I noticed we went out of our way not to
support clauses on boolean partitioned tables in the form of "IS
UNKNOWN" and "IS NOT UNKNOWN". It's almost as much code to disallow
this as it is to allow it, so let's allow it.
---
src/backend/partitioning/partprune.c | 68 +++++++++++--------
src/test/regress/expected/partition_prune.out | 56 ++++++++++++---
src/test/regress/sql/partition_prune.sql | 7 ++
3 files changed, 91 insertions(+), 40 deletions(-)
diff --git a/src/backend/partitioning/partprune.c
b/src/backend/partitioning/partprune.c
index ccb9a579b3..5382c24fb9 100644
--- a/src/backend/partitioning/partprune.c
+++ b/src/backend/partitioning/partprune.c
@@ -200,7 +200,7 @@ static PartClauseMatchStatus
match_boolean_partition_clause(Oid partopfamily,
Expr *clause,
Expr *partkey,
Expr **outconst,
-
bool *noteq);
+
bool *notclause);
static void partkey_datum_from_expr(PartitionPruneContext *context,
Expr
*expr, int stateidx,
Datum
*value, bool *isnull);
@@ -1798,13 +1798,14 @@
match_clause_to_partition_key(GeneratePruningStepsContext *context,
Oid partopfamily =
part_scheme->partopfamily[partkeyidx],
partcoll =
part_scheme->partcollation[partkeyidx];
Expr *expr;
- bool noteq;
+ bool notclause;
/*
* Recognize specially shaped clauses that match a Boolean partition
key.
*/
boolmatchstatus = match_boolean_partition_clause(partopfamily, clause,
-
partkey, &expr, ¬eq);
+
partkey, &expr,
+
¬clause);
if (boolmatchstatus == PARTCLAUSE_MATCH_CLAUSE)
{
@@ -1818,7 +1819,7 @@ match_clause_to_partition_key(GeneratePruningStepsContext
*context,
* punt it off to gen_partprune_steps_internal() to generate
pruning
* steps.
*/
- if (noteq)
+ if (notclause)
{
List *new_clauses;
List *or_clause;
@@ -1836,9 +1837,8 @@ match_clause_to_partition_key(GeneratePruningStepsContext
*context,
else
{
/*
- * We only expect
match_boolean_partition_clause to match for
- * IS_NOT_TRUE and IS_NOT_FALSE.
IS_NOT_UNKNOWN is not
- * supported.
+ * We only expect
match_boolean_partition_clause to return
+ * PARTCLAUSE_MATCH_CLAUSE for IS_NOT_TRUE and
IS_NOT_FALSE.
*/
Assert(false);
}
@@ -1876,6 +1876,15 @@
match_clause_to_partition_key(GeneratePruningStepsContext *context,
return PARTCLAUSE_MATCH_CLAUSE;
}
+ else if (boolmatchstatus == PARTCLAUSE_MATCH_NULLNESS)
+ {
+ /*
+ * Handle IS UNKNOWN and IS NOT UNKNOWN. These just logically
+ * translate to IS NULL and IS NOT NULL.
+ */
+ *clause_is_not_null = notclause;
+ return PARTCLAUSE_MATCH_NULLNESS;
+ }
else if (IsA(clause, OpExpr) &&
list_length(((OpExpr *) clause)->args) == 2)
{
@@ -3650,21 +3659,21 @@ perform_pruning_combine_step(PartitionPruneContext
*context,
*
* If we're able to match the clause to the partition key as specially-shaped
* boolean clause, set *outconst to a Const containing a true or false value,
- * set *noteq according to if the clause was in the "not" form, i.e. "is not
- * true" or "is not false", and return PARTCLAUSE_MATCH_CLAUSE. Returns
- * PARTCLAUSE_UNSUPPORTED if the clause is not a boolean clause or if the
- * boolean clause is unsuitable for partition pruning. Returns
- * PARTCLAUSE_NOMATCH if it's a bool quals but just does not match this
- * partition key. *outconst is set to NULL in the latter two cases.
+ * set *notclause according to if the clause was in the "not" form, i.e. "is
+ * not true", "is not false" or "is not unknown" and return
+ * PARTCLAUSE_MATCH_CLAUSE or PARTCLAUSE_MATCH_NULLNESS accordingly.
+ * Otherwise, returns PARTCLAUSE_UNSUPPORTED if the clause cannot be used for
+ * partition pruning, or PARTCLAUSE_NOMATCH for supported clauses that do not
+ * match this 'partkey'.
*/
static PartClauseMatchStatus
match_boolean_partition_clause(Oid partopfamily, Expr *clause, Expr *partkey,
- Expr **outconst,
bool *noteq)
+ Expr **outconst,
bool *notclause)
{
Expr *leftop;
*outconst = NULL;
- *noteq = false;
+ *notclause = false;
/*
* Partitioning currently can only use built-in AMs, so checking for
@@ -3677,11 +3686,6 @@ match_boolean_partition_clause(Oid partopfamily, Expr
*clause, Expr *partkey,
{
BooleanTest *btest = (BooleanTest *) clause;
- /* Only IS [NOT] TRUE/FALSE are any good to us */
- if (btest->booltesttype == IS_UNKNOWN ||
- btest->booltesttype == IS_NOT_UNKNOWN)
- return PARTCLAUSE_UNSUPPORTED;
-
leftop = btest->arg;
if (IsA(leftop, RelabelType))
leftop = ((RelabelType *) leftop)->arg;
@@ -3691,23 +3695,28 @@ match_boolean_partition_clause(Oid partopfamily, Expr
*clause, Expr *partkey,
switch (btest->booltesttype)
{
case IS_NOT_TRUE:
- *noteq = true;
+ *notclause = true;
/* fall through */
case IS_TRUE:
*outconst = (Expr *)
makeBoolConst(true, false);
- break;
+ return PARTCLAUSE_MATCH_CLAUSE;
case IS_NOT_FALSE:
- *noteq = true;
+ *notclause = true;
/* fall through */
case IS_FALSE:
*outconst = (Expr *)
makeBoolConst(false, false);
- break;
+ return PARTCLAUSE_MATCH_CLAUSE;
+ case IS_NOT_UNKNOWN:
+ *notclause = true;
+ /* fall through */
+ case IS_UNKNOWN:
+ return PARTCLAUSE_MATCH_NULLNESS;
default:
return PARTCLAUSE_UNSUPPORTED;
}
}
- if (*outconst)
- return PARTCLAUSE_MATCH_CLAUSE;
+ /* does not match partition key */
+ return PARTCLAUSE_NOMATCH;
}
else
{
@@ -3723,12 +3732,11 @@ match_boolean_partition_clause(Oid partopfamily, Expr
*clause, Expr *partkey,
*outconst = (Expr *) makeBoolConst(!is_not_clause,
false);
else if (equal(negate_clause((Node *) leftop), partkey))
*outconst = (Expr *) makeBoolConst(is_not_clause,
false);
+ else
+ return PARTCLAUSE_NOMATCH;
- if (*outconst)
- return PARTCLAUSE_MATCH_CLAUSE;
+ return PARTCLAUSE_MATCH_CLAUSE;
}
-
- return PARTCLAUSE_NOMATCH;
}
/*
diff --git a/src/test/regress/expected/partition_prune.out
b/src/test/regress/expected/partition_prune.out
index b41950d923..bf0657b9f2 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -1093,16 +1093,11 @@ explain (costs off) select * from boolpart where a is
not true and a is not fals
(2 rows)
explain (costs off) select * from boolpart where a is unknown;
- QUERY PLAN
------------------------------------------------
- Append
- -> Seq Scan on boolpart_f boolpart_1
- Filter: (a IS UNKNOWN)
- -> Seq Scan on boolpart_t boolpart_2
- Filter: (a IS UNKNOWN)
- -> Seq Scan on boolpart_default boolpart_3
- Filter: (a IS UNKNOWN)
-(7 rows)
+ QUERY PLAN
+---------------------------------------
+ Seq Scan on boolpart_default boolpart
+ Filter: (a IS UNKNOWN)
+(2 rows)
explain (costs off) select * from boolpart where a is not unknown;
QUERY PLAN
@@ -1200,6 +1195,18 @@ explain (costs off) select * from boolpart where a is
not false;
Filter: (a IS NOT FALSE)
(5 rows)
+explain (costs off) select * from boolpart where a is not unknown;
+ QUERY PLAN
+-----------------------------------------------
+ Append
+ -> Seq Scan on boolpart_f boolpart_1
+ Filter: (a IS NOT UNKNOWN)
+ -> Seq Scan on boolpart_t boolpart_2
+ Filter: (a IS NOT UNKNOWN)
+ -> Seq Scan on boolpart_default boolpart_3
+ Filter: (a IS NOT UNKNOWN)
+(7 rows)
+
select * from boolpart where a is not true;
a
---
@@ -1220,6 +1227,35 @@ select * from boolpart where a is not false;
(2 rows)
+select * from boolpart where a is not unknown;
+ a
+---
+ f
+ t
+(2 rows)
+
+-- check that all partitions are pruned when faced with conflicting clauses
+explain (costs off) select * from boolpart where a is not unknown and a is
unknown;
+ QUERY PLAN
+--------------------------
+ Result
+ One-Time Filter: false
+(2 rows)
+
+explain (costs off) select * from boolpart where a is false and a is unknown;
+ QUERY PLAN
+--------------------------
+ Result
+ One-Time Filter: false
+(2 rows)
+
+explain (costs off) select * from boolpart where a is true and a is unknown;
+ QUERY PLAN
+--------------------------
+ Result
+ One-Time Filter: false
+(2 rows)
+
-- inverse boolean partitioning - a seemingly unlikely design, but we've got
-- code for it, so we'd better test it.
create table iboolpart (a bool) partition by list ((not a));
diff --git a/src/test/regress/sql/partition_prune.sql
b/src/test/regress/sql/partition_prune.sql
index 7ba6a9ff37..a09b27d820 100644
--- a/src/test/regress/sql/partition_prune.sql
+++ b/src/test/regress/sql/partition_prune.sql
@@ -186,10 +186,17 @@ insert into boolpart values(null);
explain (costs off) select * from boolpart where a is not true;
explain (costs off) select * from boolpart where a is not true and a is not
false;
explain (costs off) select * from boolpart where a is not false;
+explain (costs off) select * from boolpart where a is not unknown;
select * from boolpart where a is not true;
select * from boolpart where a is not true and a is not false;
select * from boolpart where a is not false;
+select * from boolpart where a is not unknown;
+
+-- check that all partitions are pruned when faced with conflicting clauses
+explain (costs off) select * from boolpart where a is not unknown and a is
unknown;
+explain (costs off) select * from boolpart where a is false and a is unknown;
+explain (costs off) select * from boolpart where a is true and a is unknown;
-- inverse boolean partitioning - a seemingly unlikely design, but we've got
-- code for it, so we'd better test it.
--
2.40.1
