Fix bogus logic for combining range-partitioned columns during pruning.

gen_prune_steps_from_opexps's notion of how to do this was overly
complicated and underly correct.

Per discussion of a report from Alan Jackson (though this fixes only one
aspect of that problem).  Back-patch to v11 where this code came in.

Amit Langote

Discussion: https://postgr.es/m/FAD28A83-AC73-489E-A058-2681FA31D648@tvsquared.com

diff --git a/src/backend/partitioning/partprune.c b/src/backend/partitioning/partprune.c
index c12ca703e7be35bde9d899c5814c4284c3865c81..ff3caf14c0c81fc23cf46eeb7f8fb77d3469d8c4 100644 (file)
--- a/src/backend/partitioning/partprune.c
+++ b/src/backend/partitioning/partprune.c
@@ -1209,9 +1209,6 @@ gen_prune_steps_from_opexps(PartitionScheme part_scheme,
    List       *opsteps = NIL;
    List       *btree_clauses[BTMaxStrategyNumber + 1],
               *hash_clauses[HTMaxStrategyNumber + 1];
-   bool        need_next_less,
-               need_next_eq,
-               need_next_greater;
    int         i;
 
    memset(btree_clauses, 0, sizeof(btree_clauses));
@@ -1222,9 +1219,8 @@ gen_prune_steps_from_opexps(PartitionScheme part_scheme,
        bool        consider_next_key = true;
 
        /*
-        * To be useful for pruning, we must have clauses for a prefix of
-        * partition keys in the case of range partitioning.  So, ignore
-        * clauses for keys after this one.
+        * For range partitioning, if we have no clauses for the current key,
+        * we can't consider any later keys either, so we can stop here.
         */
        if (part_scheme->strategy == PARTITION_STRATEGY_RANGE &&
            clauselist == NIL)
@@ -1239,7 +1235,6 @@ gen_prune_steps_from_opexps(PartitionScheme part_scheme,
            clauselist == NIL && !bms_is_member(i, nullkeys))
            return NULL;
 
-       need_next_eq = need_next_less = need_next_greater = true;
        foreach(lc, clauselist)
        {
            PartClauseInfo *pc = (PartClauseInfo *) lfirst(lc);
@@ -1261,7 +1256,6 @@ gen_prune_steps_from_opexps(PartitionScheme part_scheme,
                case PARTITION_STRATEGY_RANGE:
                    {
                        PartClauseInfo *last = NULL;
-                       bool        inclusive = false;
 
                        /*
                         * Add this clause to the list of clauses to be used
@@ -1279,35 +1273,13 @@ gen_prune_steps_from_opexps(PartitionScheme part_scheme,
                                lappend(btree_clauses[pc->op_strategy], pc);
 
                        /*
-                        * We may not need the next clause if they're of
-                        * certain strategy.
+                        * We can't consider subsequent partition keys if the
+                        * clause for the current key contains a non-inclusive
+                        * operator.
                         */
-                       switch (pc->op_strategy)
-                       {
-                           case BTLessEqualStrategyNumber:
-                               inclusive = true;
-                               /* fall through */
-                           case BTLessStrategyNumber:
-                               if (!inclusive)
-                                   need_next_eq = need_next_less = false;
-                               break;
-                           case BTEqualStrategyNumber:
-                               /* always accept clauses for the next key. */
-                               break;
-                           case BTGreaterEqualStrategyNumber:
-                               inclusive = true;
-                               /* fall through */
-                           case BTGreaterStrategyNumber:
-                               if (!inclusive)
-                                   need_next_eq = need_next_greater = false;
-                               break;
-                       }
-
-                       /* We may want to change our mind. */
-                       if (consider_next_key)
-                           consider_next_key = (need_next_eq ||
-                                                need_next_less ||
-                                                need_next_greater);
+                       if (pc->op_strategy == BTLessStrategyNumber ||
+                           pc->op_strategy == BTGreaterStrategyNumber)
+                           consider_next_key = false;
                        break;
                    }
 
@@ -2847,7 +2819,7 @@ get_matching_range_bounds(PartitionPruneContext *context,
 
            /*
             * Look for the greatest bound that is < or <= lookup value and
-            * set minoff to its offset.
+            * set maxoff to its offset.
             */
            off = partition_range_datum_bsearch(partsupfunc,
                                                partcollation,

diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index f1e192c68c90fb05a26b0491efed217368d6106f..723fc70f732d9f44262e8fdce520f78803196d2f 100644 (file)
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -3123,6 +3123,33 @@ select * from stable_qual_pruning
 (4 rows)
 
 drop table stable_qual_pruning;
+--
+-- Check that pruning with composite range partitioning works correctly when
+-- it must ignore clauses for trailing keys once it has seen a clause with
+-- non-inclusive operator for an earlier key
+--
+create table mc3p (a int, b int, c int) partition by range (a, abs(b), c);
+create table mc3p0 partition of mc3p
+  for values from (0, 0, 0) to (0, maxvalue, maxvalue);
+create table mc3p1 partition of mc3p
+  for values from (1, 1, 1) to (2, minvalue, minvalue);
+create table mc3p2 partition of mc3p
+  for values from (2, minvalue, minvalue) to (3, maxvalue, maxvalue);
+insert into mc3p values (0, 1, 1), (1, 1, 1), (2, 1, 1);
+explain (analyze, costs off, summary off, timing off)
+select * from mc3p where a < 3 and abs(b) = 1;
+                   QUERY PLAN                    
+-------------------------------------------------
+ Append (actual rows=3 loops=1)
+   ->  Seq Scan on mc3p0 (actual rows=1 loops=1)
+         Filter: ((a < 3) AND (abs(b) = 1))
+   ->  Seq Scan on mc3p1 (actual rows=1 loops=1)
+         Filter: ((a < 3) AND (abs(b) = 1))
+   ->  Seq Scan on mc3p2 (actual rows=1 loops=1)
+         Filter: ((a < 3) AND (abs(b) = 1))
+(7 rows)
+
+drop table mc3p;
 -- Ensure runtime pruning works with initplans params with boolean types
 create table boolvalues (value bool not null);
 insert into boolvalues values('t'),('f');

diff --git a/src/test/regress/sql/partition_prune.sql b/src/test/regress/sql/partition_prune.sql
index ada9e6ae0ef5c3064e8765cab846dd292c93e140..2373bd8781d541de5385f7ec3456703995185603 100644 (file)
--- a/src/test/regress/sql/partition_prune.sql
+++ b/src/test/regress/sql/partition_prune.sql
@@ -792,6 +792,25 @@ select * from stable_qual_pruning
 
 drop table stable_qual_pruning;
 
+--
+-- Check that pruning with composite range partitioning works correctly when
+-- it must ignore clauses for trailing keys once it has seen a clause with
+-- non-inclusive operator for an earlier key
+--
+create table mc3p (a int, b int, c int) partition by range (a, abs(b), c);
+create table mc3p0 partition of mc3p
+  for values from (0, 0, 0) to (0, maxvalue, maxvalue);
+create table mc3p1 partition of mc3p
+  for values from (1, 1, 1) to (2, minvalue, minvalue);
+create table mc3p2 partition of mc3p
+  for values from (2, minvalue, minvalue) to (3, maxvalue, maxvalue);
+insert into mc3p values (0, 1, 1), (1, 1, 1), (2, 1, 1);
+
+explain (analyze, costs off, summary off, timing off)
+select * from mc3p where a < 3 and abs(b) = 1;
+
+drop table mc3p;
+
 -- Ensure runtime pruning works with initplans params with boolean types
 create table boolvalues (value bool not null);
 insert into boolvalues values('t'),('f');