prefix-efujita-v3.patch

diff --git a/src/backend/partitioning/partprune.c b/src/backend/partitioning/partprune.c
index badd31a44c..8bac2a4abb 100644
--- a/src/backend/partitioning/partprune.c
+++ b/src/backend/partitioning/partprune.c
@@ -1308,34 +1308,18 @@ gen_prune_steps_from_opexps(GeneratePruningStepsContext *context,
 			{
 				case PARTITION_STRATEGY_LIST:
 				case PARTITION_STRATEGY_RANGE:
-					{
-						PartClauseInfo *last = NULL;
-
-						/*
-						 * Add this clause to the list of clauses to be used
-						 * for pruning if this is the first such key for this
-						 * operator strategy or if it is consecutively next to
-						 * the last column for which a clause with this
-						 * operator strategy was matched.
-						 */
-						if (btree_clauses[pc->op_strategy] != NIL)
-							last = llast(btree_clauses[pc->op_strategy]);
-
-						if (last == NULL ||
-							i == last->keyno || i == last->keyno + 1)
-							btree_clauses[pc->op_strategy] =
-								lappend(btree_clauses[pc->op_strategy], pc);
+					btree_clauses[pc->op_strategy] =
+						lappend(btree_clauses[pc->op_strategy], pc);
 
-						/*
-						 * We can't consider subsequent partition keys if the
-						 * clause for the current key contains a non-inclusive
-						 * operator.
-						 */
-						if (pc->op_strategy == BTLessStrategyNumber ||
-							pc->op_strategy == BTGreaterStrategyNumber)
-							consider_next_key = false;
-						break;
-					}
+					/*
+					 * We can't consider subsequent partition keys if the
+					 * clause for the current key contains a non-inclusive
+					 * operator.
+					 */
+					if (pc->op_strategy == BTLessStrategyNumber ||
+						pc->op_strategy == BTGreaterStrategyNumber)
+						consider_next_key = false;
+					break;
 
 				case PARTITION_STRATEGY_HASH:
 					if (pc->op_strategy != HTEqualStrategyNumber)
@@ -1374,6 +1358,7 @@ gen_prune_steps_from_opexps(GeneratePruningStepsContext *context,
 				List	   *eq_clauses = btree_clauses[BTEqualStrategyNumber];
 				List	   *le_clauses = btree_clauses[BTLessEqualStrategyNumber];
 				List	   *ge_clauses = btree_clauses[BTGreaterEqualStrategyNumber];
+				bool		pk_has_clauses[PARTITION_MAX_KEYS];
 				int			strat;
 
 				/*
@@ -1396,6 +1381,35 @@ gen_prune_steps_from_opexps(GeneratePruningStepsContext *context,
 						ListCell   *lc1;
 						List	   *prefix = NIL;
 						List	   *pc_steps;
+						bool		prefix_valid = true;
+
+						/*
+						 * If this is a clause for the first partition key,
+						 * there are no preceding expressions; generate a
+						 * pruning step without a prefix.
+						 *
+						 * Note that we pass NULL for step_nullkeys, because
+						 * we don't search list/range partition bounds where
+						 * some keys are NULL.
+						 */
+						if (pc->keyno == 0)
+						{
+							Assert(pc->op_strategy == strat);
+							pc_steps = get_steps_using_prefix(context, strat,
+															  pc->op_is_ne,
+															  pc->expr,
+															  pc->cmpfn,
+															  0,
+															  NULL,
+															  NIL);
+							opsteps = list_concat(opsteps, pc_steps);
+							continue;
+						}
+
+						/* (Re-)initialize the pk_has_clauses array */
+						Assert(pc->keyno > 0);
+						for (i = 0; i < pc->keyno; i++)
+							pk_has_clauses[i] = false;
 
 						/*
 						 * Expressions from = clauses can always be in the
@@ -1408,7 +1422,10 @@ gen_prune_steps_from_opexps(GeneratePruningStepsContext *context,
 							if (eqpc->keyno == pc->keyno)
 								break;
 							if (eqpc->keyno < pc->keyno)
+							{
 								prefix = lappend(prefix, eqpc);
+								pk_has_clauses[eqpc->keyno] = true;
+							}
 						}
 
 						/*
@@ -1426,7 +1443,10 @@ gen_prune_steps_from_opexps(GeneratePruningStepsContext *context,
 								if (lepc->keyno == pc->keyno)
 									break;
 								if (lepc->keyno < pc->keyno)
+								{
 									prefix = lappend(prefix, lepc);
+									pk_has_clauses[lepc->keyno] = true;
+								}
 							}
 						}
 
@@ -1445,11 +1465,33 @@ gen_prune_steps_from_opexps(GeneratePruningStepsContext *context,
 								if (gepc->keyno == pc->keyno)
 									break;
 								if (gepc->keyno < pc->keyno)
+								{
 									prefix = lappend(prefix, gepc);
+									pk_has_clauses[gepc->keyno] = true;
+								}
 							}
 						}
 
 						/*
+						 * Check whether every earlier partition key has at
+						 * least one clause.
+						 */
+						for (i = 0; i < pc->keyno; i++)
+						{
+							if (!pk_has_clauses[i])
+							{
+								prefix_valid = false;
+								break;
+							}
+						}
+
+						/*
+						 * If prefix_valid, generate PartitionPruneStepOps.
+						 * Otherwise, we would not find clauses for a valid
+						 * subset of the partition keys anymore for the
+						 * strategy; give up on generating partition pruning
+						 * steps further for the strategy.
+						 *
 						 * As mentioned above, if 'prefix' contains multiple
 						 * expressions for the same key, the following will
 						 * generate multiple steps, one for each combination
@@ -1459,15 +1501,20 @@ gen_prune_steps_from_opexps(GeneratePruningStepsContext *context,
 						 * we don't search list/range partition bounds where
 						 * some keys are NULL.
 						 */
-						Assert(pc->op_strategy == strat);
-						pc_steps = get_steps_using_prefix(context, strat,
-														  pc->op_is_ne,
-														  pc->expr,
-														  pc->cmpfn,
-														  pc->keyno,
-														  NULL,
-														  prefix);
-						opsteps = list_concat(opsteps, pc_steps);
+						if (prefix_valid)
+						{
+							Assert(pc->op_strategy == strat);
+							pc_steps = get_steps_using_prefix(context, strat,
+															  pc->op_is_ne,
+															  pc->expr,
+															  pc->cmpfn,
+															  pc->keyno,
+															  NULL,
+															  prefix);
+							opsteps = list_concat(opsteps, pc_steps);
+						}
+						else
+							break;
 					}
 				}
 				break;
@@ -2278,23 +2325,19 @@ get_steps_using_prefix_recurse(GeneratePruningStepsContext *context,
 		for_each_cell(lc, prefix, start)
 		{
 			List	   *moresteps;
+			List	   *step_exprs1,
+					   *step_cmpfns1;
 
 			pc = lfirst(lc);
 			if (pc->keyno == cur_keyno)
 			{
-				/* clean up before starting a new recursion cycle. */
-				if (cur_keyno == 0)
-				{
-					list_free(step_exprs);
-					list_free(step_cmpfns);
-					step_exprs = list_make1(pc->expr);
-					step_cmpfns = list_make1_oid(pc->cmpfn);
-				}
-				else
-				{
-					step_exprs = lappend(step_exprs, pc->expr);
-					step_cmpfns = lappend_oid(step_cmpfns, pc->cmpfn);
-				}
+				/* Leave the original step_exprs unmodified. */
+				step_exprs1 = list_copy(step_exprs);
+				step_exprs1 = lappend(step_exprs1, pc->expr);
+
+				/* Leave the original step_cmpfns unmodified. */
+				step_cmpfns1 = list_copy(step_cmpfns);
+				step_cmpfns1 = lappend_oid(step_cmpfns1, pc->cmpfn);
 			}
 			else
 			{
@@ -2311,8 +2354,8 @@ get_steps_using_prefix_recurse(GeneratePruningStepsContext *context,
 													   step_nullkeys,
 													   prefix,
 													   next_start,
-													   step_exprs,
-													   step_cmpfns);
+													   step_exprs1,
+													   step_cmpfns1);
 			result = list_concat(result, moresteps);
 		}
 	}
@@ -2323,7 +2366,13 @@ get_steps_using_prefix_recurse(GeneratePruningStepsContext *context,
 		 * each clause with cur_keyno, which is all clauses from here onward
 		 * till the end of the list.
 		 */
-		Assert(list_length(step_exprs) == cur_keyno);
+		Assert(list_length(step_exprs) == cur_keyno ||
+			   (context->rel->part_scheme->strategy ==
+				PARTITION_STRATEGY_HASH &&
+				step_opstrategy == HTEqualStrategyNumber &&
+				!bms_is_empty(step_nullkeys) &&
+				bms_num_members(step_nullkeys) + list_length(step_exprs) + 2 ==
+				context->rel->part_scheme->partnatts));
 		for_each_cell(lc, prefix, start)
 		{
 			PartClauseInfo *pc = lfirst(lc);
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index 4315e8e0a3..10ef907c96 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -3671,3 +3671,63 @@ explain (costs off) update listp1 set a = 1 where a = 2;
 reset constraint_exclusion;
 reset enable_partition_pruning;
 drop table listp;
+create table rp_prefix_test1 (a int, b varchar) partition by range(a, b);
+create table rp_prefix_test1_p1 partition of rp_prefix_test1 for values from (1, 'a') to (1, 'b');
+create table rp_prefix_test1_p2 partition of rp_prefix_test1 for values from (2, 'a') to (2, 'b');
+explain (costs off) select * from rp_prefix_test1 where a <= 1 and b = 'a';
+                    QUERY PLAN                    
+--------------------------------------------------
+ Seq Scan on rp_prefix_test1_p1 rp_prefix_test1
+   Filter: ((a <= 1) AND ((b)::text = 'a'::text))
+(2 rows)
+
+explain (costs off) select * from rp_prefix_test1 where a <= 2 and b = 'a';
+                       QUERY PLAN                       
+--------------------------------------------------------
+ Append
+   ->  Seq Scan on rp_prefix_test1_p1 rp_prefix_test1_1
+         Filter: ((a <= 2) AND ((b)::text = 'a'::text))
+   ->  Seq Scan on rp_prefix_test1_p2 rp_prefix_test1_2
+         Filter: ((a <= 2) AND ((b)::text = 'a'::text))
+(5 rows)
+
+create table rp_prefix_test2 (a int, b int, c int) partition by range(a, b, c);
+create table rp_prefix_test2_p1 partition of rp_prefix_test2 for values from (1, 1, 0) to (1, 1, 10);
+create table rp_prefix_test2_p2 partition of rp_prefix_test2 for values from (2, 2, 0) to (2, 2, 10);
+explain (costs off) select * from rp_prefix_test2 where a <= 1 and b = 1 and c >= 0;
+                   QUERY PLAN                   
+------------------------------------------------
+ Seq Scan on rp_prefix_test2_p1 rp_prefix_test2
+   Filter: ((a <= 1) AND (c >= 0) AND (b = 1))
+(2 rows)
+
+explain (costs off) select * from rp_prefix_test2 where a <= 2 and b = 2 and c >= 0;
+                       QUERY PLAN                       
+--------------------------------------------------------
+ Append
+   ->  Seq Scan on rp_prefix_test2_p1 rp_prefix_test2_1
+         Filter: ((a <= 2) AND (c >= 0) AND (b = 2))
+   ->  Seq Scan on rp_prefix_test2_p2 rp_prefix_test2_2
+         Filter: ((a <= 2) AND (c >= 0) AND (b = 2))
+(5 rows)
+
+create table rp_prefix_test3 (a int, b int, c int, d int) partition by range(a, b, c, d);
+create table rp_prefix_test3_p1 partition of rp_prefix_test3 for values from (1, 1, 1, 0) to (1, 1, 1, 10);
+create table rp_prefix_test3_p2 partition of rp_prefix_test3 for values from (2, 2, 2, 0) to (2, 2, 2, 10);
+explain (costs off) select * from rp_prefix_test3 where a >= 1 and b >= 1 and b >= 2 and c >= 2 and d >= 0;
+                                QUERY PLAN                                
+--------------------------------------------------------------------------
+ Seq Scan on rp_prefix_test3_p2 rp_prefix_test3
+   Filter: ((a >= 1) AND (b >= 1) AND (b >= 2) AND (c >= 2) AND (d >= 0))
+(2 rows)
+
+create table hp_prefix_test (a int, b int, c int, d int) partition by hash (a part_test_int4_ops, b part_test_int4_ops, c part_test_int4_ops, d part_test_int4_ops);
+create table hp_prefix_test_p1 partition of hp_prefix_test for values with (modulus 2, remainder 0);
+create table hp_prefix_test_p2 partition of hp_prefix_test for values with (modulus 2, remainder 1);
+explain (costs off) select * from hp_prefix_test where a = 1 and b is null and c = 1 and d = 1;
+                         QUERY PLAN                          
+-------------------------------------------------------------
+ Seq Scan on hp_prefix_test_p1 hp_prefix_test
+   Filter: ((b IS NULL) AND (a = 1) AND (c = 1) AND (d = 1))
+(2 rows)
+
diff --git a/src/test/regress/sql/partition_prune.sql b/src/test/regress/sql/partition_prune.sql
index 6658455a74..628be0901e 100644
--- a/src/test/regress/sql/partition_prune.sql
+++ b/src/test/regress/sql/partition_prune.sql
@@ -1050,3 +1050,29 @@ reset constraint_exclusion;
 reset enable_partition_pruning;
 
 drop table listp;
+
+create table rp_prefix_test1 (a int, b varchar) partition by range(a, b);
+create table rp_prefix_test1_p1 partition of rp_prefix_test1 for values from (1, 'a') to (1, 'b');
+create table rp_prefix_test1_p2 partition of rp_prefix_test1 for values from (2, 'a') to (2, 'b');
+
+explain (costs off) select * from rp_prefix_test1 where a <= 1 and b = 'a';
+explain (costs off) select * from rp_prefix_test1 where a <= 2 and b = 'a';
+
+create table rp_prefix_test2 (a int, b int, c int) partition by range(a, b, c);
+create table rp_prefix_test2_p1 partition of rp_prefix_test2 for values from (1, 1, 0) to (1, 1, 10);
+create table rp_prefix_test2_p2 partition of rp_prefix_test2 for values from (2, 2, 0) to (2, 2, 10);
+
+explain (costs off) select * from rp_prefix_test2 where a <= 1 and b = 1 and c >= 0;
+explain (costs off) select * from rp_prefix_test2 where a <= 2 and b = 2 and c >= 0;
+
+create table rp_prefix_test3 (a int, b int, c int, d int) partition by range(a, b, c, d);
+create table rp_prefix_test3_p1 partition of rp_prefix_test3 for values from (1, 1, 1, 0) to (1, 1, 1, 10);
+create table rp_prefix_test3_p2 partition of rp_prefix_test3 for values from (2, 2, 2, 0) to (2, 2, 2, 10);
+
+explain (costs off) select * from rp_prefix_test3 where a >= 1 and b >= 1 and b >= 2 and c >= 2 and d >= 0;
+
+create table hp_prefix_test (a int, b int, c int, d int) partition by hash (a part_test_int4_ops, b part_test_int4_ops, c part_test_int4_ops, d part_test_int4_ops);
+create table hp_prefix_test_p1 partition of hp_prefix_test for values with (modulus 2, remainder 0);
+create table hp_prefix_test_p2 partition of hp_prefix_test for values with (modulus 2, remainder 1);
+
+explain (costs off) select * from hp_prefix_test where a = 1 and b is null and c = 1 and d = 1;