Show index search count in EXPLAIN ANALYZE, take 2.

Expose the count of index searches/index descents in EXPLAIN ANALYZE's
output for index scan/index-only scan/bitmap index scan nodes.  This
information is particularly useful with scans that use ScalarArrayOp
quals, where the number of index searches can be unpredictable due to
implementation details that interact with physical index characteristics
(at least with nbtree SAOP scans, since Postgres 17 commit 5bf748b8).
The information shown also provides useful context when EXPLAIN ANALYZE
runs a plan with an index scan node that successfully applied the skip
scan optimization (set to be added to nbtree by an upcoming patch).

The instrumentation works by teaching all index AMs to increment a new
nsearches counter whenever a new index search begins.  The counter is
incremented at exactly the same point that index AMs already increment
the pg_stat_*_indexes.idx_scan counter (we're counting the same event,
but at the scan level rather than the relation level).  Parallel queries
have workers copy their local counter struct into shared memory when an
index scan node ends -- even when it isn't a parallel aware scan node.
An earlier version of this patch that only worked with parallel aware
scans became commit 5ead85fb (though that was quickly reverted by commit
d00107cd following "debug_parallel_query=regress" buildfarm failures).

Our approach doesn't match the approach used when tracking other index
scan related costs (e.g., "Rows Removed by Filter:").  It is comparable
to the approach used in similar cases involving costs that are only
readily accessible inside an access method, not from the executor proper
(e.g., "Heap Blocks:" output for a Bitmap Heap Scan, which was recently
enhanced to show per-worker costs by commit 5a1e6df3, using essentially
the same scheme as the one used here).  It is necessary for index AMs to
have direct responsibility for maintaining the new counter, since the
counter might need to be incremented multiple times per amgettuple call
(or per amgetbitmap call).  But it is also necessary for the executor
proper to manage the shared memory now used to transfer each worker's
counter struct to the leader.

Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Reviewed-By: Tomas Vondra <tomas@vondra.me>
Reviewed-By: Masahiro Ikeda <ikedamsh@oss.nttdata.com>
Reviewed-By: Matthias van de Meent <boekewurm+postgres@gmail.com>
Discussion: https://postgr.es/m/CAH2-WzkRqvaqR2CTNqTZP0z6FuL4-3ED6eQB0yx38XBNj1v-4Q@mail.gmail.com
Discussion: https://postgr.es/m/CAH2-Wz=PKR6rB7qbx+Vnd7eqeB5VTcrW=iJvAsTsKbdG+kW_UA@mail.gmail.com

6 files changed, 148 insertions, 40 deletions

diff --git a/src/test/regress/expected/brin_multi.out b/src/test/regress/expected/brin_multi.out
index 991b7eacada..cb5b5e53e86 100644
--- a/src/test/regress/expected/brin_multi.out
+++ b/src/test/regress/expected/brin_multi.out
@@ -853,7 +853,8 @@ SELECT * FROM brin_date_test WHERE a = '2023-01-01'::date;
    Recheck Cond: (a = '2023-01-01'::date)
    ->  Bitmap Index Scan on brin_date_test_a_idx (actual rows=0.00 loops=1)
          Index Cond: (a = '2023-01-01'::date)
-(4 rows)
+         Index Searches: 1
+(5 rows)
 
 DROP TABLE brin_date_test;
 RESET enable_seqscan;
@@ -872,7 +873,8 @@ SELECT * FROM brin_timestamp_test WHERE a = '2023-01-01'::timestamp;
    Recheck Cond: (a = '2023-01-01 00:00:00'::timestamp without time zone)
    ->  Bitmap Index Scan on brin_timestamp_test_a_idx (actual rows=0.00 loops=1)
          Index Cond: (a = '2023-01-01 00:00:00'::timestamp without time zone)
-(4 rows)
+         Index Searches: 1
+(5 rows)
 
 EXPLAIN (ANALYZE, TIMING OFF, COSTS OFF, SUMMARY OFF, BUFFERS OFF)
 SELECT * FROM brin_timestamp_test WHERE a = '1900-01-01'::timestamp;
@@ -882,7 +884,8 @@ SELECT * FROM brin_timestamp_test WHERE a = '1900-01-01'::timestamp;
    Recheck Cond: (a = '1900-01-01 00:00:00'::timestamp without time zone)
    ->  Bitmap Index Scan on brin_timestamp_test_a_idx (actual rows=0.00 loops=1)
          Index Cond: (a = '1900-01-01 00:00:00'::timestamp without time zone)
-(4 rows)
+         Index Searches: 1
+(5 rows)
 
 DROP TABLE brin_timestamp_test;
 RESET enable_seqscan;
@@ -900,7 +903,8 @@ SELECT * FROM brin_date_test WHERE a = '2023-01-01'::date;
    Recheck Cond: (a = '2023-01-01'::date)
    ->  Bitmap Index Scan on brin_date_test_a_idx (actual rows=0.00 loops=1)
          Index Cond: (a = '2023-01-01'::date)
-(4 rows)
+         Index Searches: 1
+(5 rows)
 
 EXPLAIN (ANALYZE, TIMING OFF, COSTS OFF, SUMMARY OFF, BUFFERS OFF)
 SELECT * FROM brin_date_test WHERE a = '1900-01-01'::date;
@@ -910,7 +914,8 @@ SELECT * FROM brin_date_test WHERE a = '1900-01-01'::date;
    Recheck Cond: (a = '1900-01-01'::date)
    ->  Bitmap Index Scan on brin_date_test_a_idx (actual rows=0.00 loops=1)
          Index Cond: (a = '1900-01-01'::date)
-(4 rows)
+         Index Searches: 1
+(5 rows)
 
 DROP TABLE brin_date_test;
 RESET enable_seqscan;
@@ -929,7 +934,8 @@ SELECT * FROM brin_interval_test WHERE a = '-30 years'::interval;
    Recheck Cond: (a = '@ 30 years ago'::interval)
    ->  Bitmap Index Scan on brin_interval_test_a_idx (actual rows=0.00 loops=1)
          Index Cond: (a = '@ 30 years ago'::interval)
-(4 rows)
+         Index Searches: 1
+(5 rows)
 
 EXPLAIN (ANALYZE, TIMING OFF, COSTS OFF, SUMMARY OFF, BUFFERS OFF)
 SELECT * FROM brin_interval_test WHERE a = '30 years'::interval;
@@ -939,7 +945,8 @@ SELECT * FROM brin_interval_test WHERE a = '30 years'::interval;
    Recheck Cond: (a = '@ 30 years'::interval)
    ->  Bitmap Index Scan on brin_interval_test_a_idx (actual rows=0.00 loops=1)
          Index Cond: (a = '@ 30 years'::interval)
-(4 rows)
+         Index Searches: 1
+(5 rows)
 
 DROP TABLE brin_interval_test;
 RESET enable_seqscan;
@@ -957,7 +964,8 @@ SELECT * FROM brin_interval_test WHERE a = '-30 years'::interval;
    Recheck Cond: (a = '@ 30 years ago'::interval)
    ->  Bitmap Index Scan on brin_interval_test_a_idx (actual rows=0.00 loops=1)
          Index Cond: (a = '@ 30 years ago'::interval)
-(4 rows)
+         Index Searches: 1
+(5 rows)
 
 EXPLAIN (ANALYZE, TIMING OFF, COSTS OFF, SUMMARY OFF, BUFFERS OFF)
 SELECT * FROM brin_interval_test WHERE a = '30 years'::interval;
@@ -967,7 +975,8 @@ SELECT * FROM brin_interval_test WHERE a = '30 years'::interval;
    Recheck Cond: (a = '@ 30 years'::interval)
    ->  Bitmap Index Scan on brin_interval_test_a_idx (actual rows=0.00 loops=1)
          Index Cond: (a = '@ 30 years'::interval)
-(4 rows)
+         Index Searches: 1
+(5 rows)
 
 DROP TABLE brin_interval_test;
 RESET enable_seqscan;
diff --git a/src/test/regress/expected/memoize.out b/src/test/regress/expected/memoize.out
index 22f2d32845e..38dfaf021c9 100644
--- a/src/test/regress/expected/memoize.out
+++ b/src/test/regress/expected/memoize.out
@@ -22,8 +22,9 @@ begin
         ln := regexp_replace(ln, 'Evictions: 0', 'Evictions: Zero');
         ln := regexp_replace(ln, 'Evictions: \d+', 'Evictions: N');
         ln := regexp_replace(ln, 'Memory Usage: \d+', 'Memory Usage: N');
-	ln := regexp_replace(ln, 'Heap Fetches: \d+', 'Heap Fetches: N');
-	ln := regexp_replace(ln, 'loops=\d+', 'loops=N');
+        ln := regexp_replace(ln, 'Heap Fetches: \d+', 'Heap Fetches: N');
+        ln := regexp_replace(ln, 'loops=\d+', 'loops=N');
+        ln := regexp_replace(ln, 'Index Searches: \d+', 'Index Searches: N');
         return next ln;
     end loop;
 end;
@@ -49,7 +50,8 @@ WHERE t2.unique1 < 1000;', false);
                ->  Index Only Scan using tenk1_unique1 on tenk1 t1 (actual rows=1.00 loops=N)
                      Index Cond: (unique1 = t2.twenty)
                      Heap Fetches: N
-(12 rows)
+                     Index Searches: N
+(13 rows)
 
 -- And check we get the expected results.
 SELECT COUNT(*),AVG(t1.unique1) FROM tenk1 t1
@@ -80,7 +82,8 @@ WHERE t1.unique1 < 1000;', false);
                ->  Index Only Scan using tenk1_unique1 on tenk1 t2 (actual rows=1.00 loops=N)
                      Index Cond: (unique1 = t1.twenty)
                      Heap Fetches: N
-(12 rows)
+                     Index Searches: N
+(13 rows)
 
 -- And check we get the expected results.
 SELECT COUNT(*),AVG(t2.unique1) FROM tenk1 t1,
@@ -106,6 +109,7 @@ WHERE t1.unique1 < 10;', false);
    ->  Nested Loop Left Join (actual rows=20.00 loops=N)
          ->  Index Scan using tenk1_unique1 on tenk1 t1 (actual rows=10.00 loops=N)
                Index Cond: (unique1 < 10)
+               Index Searches: N
          ->  Memoize (actual rows=2.00 loops=N)
                Cache Key: t1.two
                Cache Mode: binary
@@ -115,7 +119,8 @@ WHERE t1.unique1 < 10;', false);
                      Rows Removed by Filter: 2
                      ->  Index Scan using tenk1_unique1 on tenk1 t2_1 (actual rows=4.00 loops=N)
                            Index Cond: (unique1 < 4)
-(13 rows)
+                           Index Searches: N
+(15 rows)
 
 -- And check we get the expected results.
 SELECT COUNT(*),AVG(t2.t1two) FROM tenk1 t1 LEFT JOIN
@@ -149,7 +154,8 @@ WHERE s.c1 = s.c2 AND t1.unique1 < 1000;', false);
                      Filter: ((t1.two + 1) = unique1)
                      Rows Removed by Filter: 9999
                      Heap Fetches: N
-(13 rows)
+                     Index Searches: N
+(14 rows)
 
 -- And check we get the expected results.
 SELECT COUNT(*), AVG(t1.twenty) FROM tenk1 t1 LEFT JOIN
@@ -219,7 +225,8 @@ ON t1.x = t2.t::numeric AND t1.t::numeric = t2.x;', false);
                Index Cond: (x = (t1.t)::numeric)
                Filter: (t1.x = (t)::numeric)
                Heap Fetches: N
-(10 rows)
+               Index Searches: N
+(11 rows)
 
 DROP TABLE expr_key;
 -- Reduce work_mem and hash_mem_multiplier so that we see some cache evictions
@@ -246,7 +253,8 @@ WHERE t2.unique1 < 1200;', true);
                ->  Index Only Scan using tenk1_unique1 on tenk1 t1 (actual rows=1.00 loops=N)
                      Index Cond: (unique1 = t2.thousand)
                      Heap Fetches: N
-(12 rows)
+                     Index Searches: N
+(13 rows)
 
 CREATE TABLE flt (f float);
 CREATE INDEX flt_f_idx ON flt (f);
@@ -261,6 +269,7 @@ SELECT * FROM flt f1 INNER JOIN flt f2 ON f1.f = f2.f;', false);
  Nested Loop (actual rows=4.00 loops=N)
    ->  Index Only Scan using flt_f_idx on flt f1 (actual rows=2.00 loops=N)
          Heap Fetches: N
+         Index Searches: N
    ->  Memoize (actual rows=2.00 loops=N)
          Cache Key: f1.f
          Cache Mode: logical
@@ -268,7 +277,8 @@ SELECT * FROM flt f1 INNER JOIN flt f2 ON f1.f = f2.f;', false);
          ->  Index Only Scan using flt_f_idx on flt f2 (actual rows=2.00 loops=N)
                Index Cond: (f = f1.f)
                Heap Fetches: N
-(10 rows)
+               Index Searches: N
+(12 rows)
 
 -- Ensure memoize operates in binary mode
 SELECT explain_memoize('
@@ -278,6 +288,7 @@ SELECT * FROM flt f1 INNER JOIN flt f2 ON f1.f >= f2.f;', false);
  Nested Loop (actual rows=4.00 loops=N)
    ->  Index Only Scan using flt_f_idx on flt f1 (actual rows=2.00 loops=N)
          Heap Fetches: N
+         Index Searches: N
    ->  Memoize (actual rows=2.00 loops=N)
          Cache Key: f1.f
          Cache Mode: binary
@@ -285,7 +296,8 @@ SELECT * FROM flt f1 INNER JOIN flt f2 ON f1.f >= f2.f;', false);
          ->  Index Only Scan using flt_f_idx on flt f2 (actual rows=2.00 loops=N)
                Index Cond: (f <= f1.f)
                Heap Fetches: N
-(10 rows)
+               Index Searches: N
+(12 rows)
 
 DROP TABLE flt;
 -- Exercise Memoize in binary mode with a large fixed width type and a
@@ -311,7 +323,8 @@ SELECT * FROM strtest s1 INNER JOIN strtest s2 ON s1.n >= s2.n;', false);
          Hits: 3  Misses: 3  Evictions: Zero  Overflows: 0  Memory Usage: NkB
          ->  Index Scan using strtest_n_idx on strtest s2 (actual rows=4.00 loops=N)
                Index Cond: (n <= s1.n)
-(9 rows)
+               Index Searches: N
+(10 rows)
 
 -- Ensure we get 3 hits and 3 misses
 SELECT explain_memoize('
@@ -327,7 +340,8 @@ SELECT * FROM strtest s1 INNER JOIN strtest s2 ON s1.t >= s2.t;', false);
          Hits: 3  Misses: 3  Evictions: Zero  Overflows: 0  Memory Usage: NkB
          ->  Index Scan using strtest_t_idx on strtest s2 (actual rows=4.00 loops=N)
                Index Cond: (t <= s1.t)
-(9 rows)
+               Index Searches: N
+(10 rows)
 
 DROP TABLE strtest;
 -- Ensure memoize works with partitionwise join
@@ -348,6 +362,7 @@ SELECT * FROM prt t1 INNER JOIN prt t2 ON t1.a = t2.a;', false);
    ->  Nested Loop (actual rows=16.00 loops=N)
          ->  Index Only Scan using iprt_p1_a on prt_p1 t1_1 (actual rows=4.00 loops=N)
                Heap Fetches: N
+               Index Searches: N
          ->  Memoize (actual rows=4.00 loops=N)
                Cache Key: t1_1.a
                Cache Mode: logical
@@ -355,9 +370,11 @@ SELECT * FROM prt t1 INNER JOIN prt t2 ON t1.a = t2.a;', false);
                ->  Index Only Scan using iprt_p1_a on prt_p1 t2_1 (actual rows=4.00 loops=N)
                      Index Cond: (a = t1_1.a)
                      Heap Fetches: N
+                     Index Searches: N
    ->  Nested Loop (actual rows=16.00 loops=N)
          ->  Index Only Scan using iprt_p2_a on prt_p2 t1_2 (actual rows=4.00 loops=N)
                Heap Fetches: N
+               Index Searches: N
          ->  Memoize (actual rows=4.00 loops=N)
                Cache Key: t1_2.a
                Cache Mode: logical
@@ -365,7 +382,8 @@ SELECT * FROM prt t1 INNER JOIN prt t2 ON t1.a = t2.a;', false);
                ->  Index Only Scan using iprt_p2_a on prt_p2 t2_2 (actual rows=4.00 loops=N)
                      Index Cond: (a = t1_2.a)
                      Heap Fetches: N
-(21 rows)
+                     Index Searches: N
+(25 rows)
 
 -- Ensure memoize works with parameterized union-all Append path
 SET enable_partitionwise_join TO off;
@@ -378,6 +396,7 @@ ON t1.a = t2.a;', false);
  Nested Loop (actual rows=16.00 loops=N)
    ->  Index Only Scan using iprt_p1_a on prt_p1 t1 (actual rows=4.00 loops=N)
          Heap Fetches: N
+         Index Searches: N
    ->  Memoize (actual rows=4.00 loops=N)
          Cache Key: t1.a
          Cache Mode: logical
@@ -386,10 +405,12 @@ ON t1.a = t2.a;', false);
                ->  Index Only Scan using iprt_p1_a on prt_p1 (actual rows=4.00 loops=N)
                      Index Cond: (a = t1.a)
                      Heap Fetches: N
+                     Index Searches: N
                ->  Index Only Scan using iprt_p2_a on prt_p2 (actual rows=0.00 loops=N)
                      Index Cond: (a = t1.a)
                      Heap Fetches: N
-(14 rows)
+                     Index Searches: N
+(17 rows)
 
 DROP TABLE prt;
 RESET enable_partitionwise_join;
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index d95d2395d48..34f2b0b8dbd 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -2369,6 +2369,10 @@ begin
         ln := regexp_replace(ln, 'Workers Launched: \d+', 'Workers Launched: N');
         ln := regexp_replace(ln, 'actual rows=\d+(?:\.\d+)? loops=\d+', 'actual rows=N loops=N');
         ln := regexp_replace(ln, 'Rows Removed by Filter: \d+', 'Rows Removed by Filter: N');
+        perform regexp_matches(ln, 'Index Searches: \d+');
+        if found then
+          continue;
+        end if;
         return next ln;
     end loop;
 end;
@@ -2686,47 +2690,56 @@ select * from ab where a = (select max(a) from lprt_a) and b = (select max(a)-1
          Filter: (b = (InitPlan 2).col1)
          ->  Bitmap Index Scan on ab_a1_b1_a_idx (never executed)
                Index Cond: (a = (InitPlan 1).col1)
+               Index Searches: 0
    ->  Bitmap Heap Scan on ab_a1_b2 ab_2 (never executed)
          Recheck Cond: (a = (InitPlan 1).col1)
          Filter: (b = (InitPlan 2).col1)
          ->  Bitmap Index Scan on ab_a1_b2_a_idx (never executed)
                Index Cond: (a = (InitPlan 1).col1)
+               Index Searches: 0
    ->  Bitmap Heap Scan on ab_a1_b3 ab_3 (never executed)
          Recheck Cond: (a = (InitPlan 1).col1)
          Filter: (b = (InitPlan 2).col1)
          ->  Bitmap Index Scan on ab_a1_b3_a_idx (never executed)
                Index Cond: (a = (InitPlan 1).col1)
+               Index Searches: 0
    ->  Bitmap Heap Scan on ab_a2_b1 ab_4 (never executed)
          Recheck Cond: (a = (InitPlan 1).col1)
          Filter: (b = (InitPlan 2).col1)
          ->  Bitmap Index Scan on ab_a2_b1_a_idx (never executed)
                Index Cond: (a = (InitPlan 1).col1)
+               Index Searches: 0
    ->  Bitmap Heap Scan on ab_a2_b2 ab_5 (never executed)
          Recheck Cond: (a = (InitPlan 1).col1)
          Filter: (b = (InitPlan 2).col1)
          ->  Bitmap Index Scan on ab_a2_b2_a_idx (never executed)
                Index Cond: (a = (InitPlan 1).col1)
+               Index Searches: 0
    ->  Bitmap Heap Scan on ab_a2_b3 ab_6 (never executed)
          Recheck Cond: (a = (InitPlan 1).col1)
          Filter: (b = (InitPlan 2).col1)
          ->  Bitmap Index Scan on ab_a2_b3_a_idx (never executed)
                Index Cond: (a = (InitPlan 1).col1)
+               Index Searches: 0
    ->  Bitmap Heap Scan on ab_a3_b1 ab_7 (never executed)
          Recheck Cond: (a = (InitPlan 1).col1)
          Filter: (b = (InitPlan 2).col1)
          ->  Bitmap Index Scan on ab_a3_b1_a_idx (never executed)
                Index Cond: (a = (InitPlan 1).col1)
+               Index Searches: 0
    ->  Bitmap Heap Scan on ab_a3_b2 ab_8 (actual rows=0.00 loops=1)
          Recheck Cond: (a = (InitPlan 1).col1)
          Filter: (b = (InitPlan 2).col1)
          ->  Bitmap Index Scan on ab_a3_b2_a_idx (actual rows=0.00 loops=1)
                Index Cond: (a = (InitPlan 1).col1)
+               Index Searches: 1
    ->  Bitmap Heap Scan on ab_a3_b3 ab_9 (never executed)
          Recheck Cond: (a = (InitPlan 1).col1)
          Filter: (b = (InitPlan 2).col1)
          ->  Bitmap Index Scan on ab_a3_b3_a_idx (never executed)
                Index Cond: (a = (InitPlan 1).col1)
-(52 rows)
+               Index Searches: 0
+(61 rows)
 
 -- Test run-time partition pruning with UNION ALL parents
 explain (analyze, costs off, summary off, timing off, buffers off)
@@ -2742,16 +2755,19 @@ select * from (select * from ab where a = 1 union all select * from ab) ab where
                Filter: (b = (InitPlan 1).col1)
                ->  Bitmap Index Scan on ab_a1_b1_a_idx (actual rows=0.00 loops=1)
                      Index Cond: (a = 1)
+                     Index Searches: 1
          ->  Bitmap Heap Scan on ab_a1_b2 ab_12 (never executed)
                Recheck Cond: (a = 1)
                Filter: (b = (InitPlan 1).col1)
                ->  Bitmap Index Scan on ab_a1_b2_a_idx (never executed)
                      Index Cond: (a = 1)
+                     Index Searches: 0
          ->  Bitmap Heap Scan on ab_a1_b3 ab_13 (never executed)
                Recheck Cond: (a = 1)
                Filter: (b = (InitPlan 1).col1)
                ->  Bitmap Index Scan on ab_a1_b3_a_idx (never executed)
                      Index Cond: (a = 1)
+                     Index Searches: 0
    ->  Seq Scan on ab_a1_b1 ab_1 (actual rows=0.00 loops=1)
          Filter: (b = (InitPlan 1).col1)
    ->  Seq Scan on ab_a1_b2 ab_2 (never executed)
@@ -2770,7 +2786,7 @@ select * from (select * from ab where a = 1 union all select * from ab) ab where
          Filter: (b = (InitPlan 1).col1)
    ->  Seq Scan on ab_a3_b3 ab_9 (never executed)
          Filter: (b = (InitPlan 1).col1)
-(37 rows)
+(40 rows)
 
 -- A case containing a UNION ALL with a non-partitioned child.
 explain (analyze, costs off, summary off, timing off, buffers off)
@@ -2786,16 +2802,19 @@ select * from (select * from ab where a = 1 union all (values(10,5)) union all s
                Filter: (b = (InitPlan 1).col1)
                ->  Bitmap Index Scan on ab_a1_b1_a_idx (actual rows=0.00 loops=1)
                      Index Cond: (a = 1)
+                     Index Searches: 1
          ->  Bitmap Heap Scan on ab_a1_b2 ab_12 (never executed)
                Recheck Cond: (a = 1)
                Filter: (b = (InitPlan 1).col1)
                ->  Bitmap Index Scan on ab_a1_b2_a_idx (never executed)
                      Index Cond: (a = 1)
+                     Index Searches: 0
          ->  Bitmap Heap Scan on ab_a1_b3 ab_13 (never executed)
                Recheck Cond: (a = 1)
                Filter: (b = (InitPlan 1).col1)
                ->  Bitmap Index Scan on ab_a1_b3_a_idx (never executed)
                      Index Cond: (a = 1)
+                     Index Searches: 0
    ->  Result (actual rows=0.00 loops=1)
          One-Time Filter: (5 = (InitPlan 1).col1)
    ->  Seq Scan on ab_a1_b1 ab_1 (actual rows=0.00 loops=1)
@@ -2816,7 +2835,7 @@ select * from (select * from ab where a = 1 union all (values(10,5)) union all s
          Filter: (b = (InitPlan 1).col1)
    ->  Seq Scan on ab_a3_b3 ab_9 (never executed)
          Filter: (b = (InitPlan 1).col1)
-(39 rows)
+(42 rows)
 
 -- Another UNION ALL test, but containing a mix of exec init and exec run-time pruning.
 create table xy_1 (x int, y int);
@@ -2887,16 +2906,19 @@ update ab_a1 set b = 3 from ab where ab.a = 1 and ab.a = ab_a1.a;');
                      Recheck Cond: (a = 1)
                      ->  Bitmap Index Scan on ab_a1_b1_a_idx (actual rows=0.00 loops=1)
                            Index Cond: (a = 1)
+                           Index Searches: 1
                ->  Bitmap Heap Scan on ab_a1_b2 ab_a1_2 (actual rows=1.00 loops=1)
                      Recheck Cond: (a = 1)
                      Heap Blocks: exact=1
                      ->  Bitmap Index Scan on ab_a1_b2_a_idx (actual rows=1.00 loops=1)
                            Index Cond: (a = 1)
+                           Index Searches: 1
                ->  Bitmap Heap Scan on ab_a1_b3 ab_a1_3 (actual rows=0.00 loops=1)
                      Recheck Cond: (a = 1)
                      Heap Blocks: exact=1
                      ->  Bitmap Index Scan on ab_a1_b3_a_idx (actual rows=1.00 loops=1)
                            Index Cond: (a = 1)
+                           Index Searches: 1
          ->  Materialize (actual rows=1.00 loops=1)
                Storage: Memory  Maximum Storage: NkB
                ->  Append (actual rows=1.00 loops=1)
@@ -2904,17 +2926,20 @@ update ab_a1 set b = 3 from ab where ab.a = 1 and ab.a = ab_a1.a;');
                            Recheck Cond: (a = 1)
                            ->  Bitmap Index Scan on ab_a1_b1_a_idx (actual rows=0.00 loops=1)
                                  Index Cond: (a = 1)
+                                 Index Searches: 1
                      ->  Bitmap Heap Scan on ab_a1_b2 ab_2 (actual rows=1.00 loops=1)
                            Recheck Cond: (a = 1)
                            Heap Blocks: exact=1
                            ->  Bitmap Index Scan on ab_a1_b2_a_idx (actual rows=1.00 loops=1)
                                  Index Cond: (a = 1)
+                                 Index Searches: 1
                      ->  Bitmap Heap Scan on ab_a1_b3 ab_3 (actual rows=0.00 loops=1)
                            Recheck Cond: (a = 1)
                            Heap Blocks: exact=1
                            ->  Bitmap Index Scan on ab_a1_b3_a_idx (actual rows=1.00 loops=1)
                                  Index Cond: (a = 1)
-(37 rows)
+                                 Index Searches: 1
+(43 rows)
 
 table ab;
  a | b 
@@ -2990,17 +3015,23 @@ select * from tbl1 join tprt on tbl1.col1 > tprt.col1;
    ->  Append (actual rows=3.00 loops=2)
          ->  Index Scan using tprt1_idx on tprt_1 (actual rows=2.00 loops=2)
                Index Cond: (col1 < tbl1.col1)
+               Index Searches: 2
          ->  Index Scan using tprt2_idx on tprt_2 (actual rows=2.00 loops=1)
                Index Cond: (col1 < tbl1.col1)
+               Index Searches: 1
          ->  Index Scan using tprt3_idx on tprt_3 (never executed)
                Index Cond: (col1 < tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt4_idx on tprt_4 (never executed)
                Index Cond: (col1 < tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt5_idx on tprt_5 (never executed)
                Index Cond: (col1 < tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt6_idx on tprt_6 (never executed)
                Index Cond: (col1 < tbl1.col1)
-(15 rows)
+               Index Searches: 0
+(21 rows)
 
 explain (analyze, costs off, summary off, timing off, buffers off)
 select * from tbl1 join tprt on tbl1.col1 = tprt.col1;
@@ -3011,17 +3042,23 @@ select * from tbl1 join tprt on tbl1.col1 = tprt.col1;
    ->  Append (actual rows=1.00 loops=2)
          ->  Index Scan using tprt1_idx on tprt_1 (never executed)
                Index Cond: (col1 = tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt2_idx on tprt_2 (actual rows=1.00 loops=2)
                Index Cond: (col1 = tbl1.col1)
+               Index Searches: 2
          ->  Index Scan using tprt3_idx on tprt_3 (never executed)
                Index Cond: (col1 = tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt4_idx on tprt_4 (never executed)
                Index Cond: (col1 = tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt5_idx on tprt_5 (never executed)
                Index Cond: (col1 = tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt6_idx on tprt_6 (never executed)
                Index Cond: (col1 = tbl1.col1)
-(15 rows)
+               Index Searches: 0
+(21 rows)
 
 select tbl1.col1, tprt.col1 from tbl1
 inner join tprt on tbl1.col1 > tprt.col1
@@ -3056,17 +3093,23 @@ select * from tbl1 inner join tprt on tbl1.col1 > tprt.col1;
    ->  Append (actual rows=4.60 loops=5)
          ->  Index Scan using tprt1_idx on tprt_1 (actual rows=2.00 loops=5)
                Index Cond: (col1 < tbl1.col1)
+               Index Searches: 5
          ->  Index Scan using tprt2_idx on tprt_2 (actual rows=2.75 loops=4)
                Index Cond: (col1 < tbl1.col1)
+               Index Searches: 4
          ->  Index Scan using tprt3_idx on tprt_3 (actual rows=1.00 loops=2)
                Index Cond: (col1 < tbl1.col1)
+               Index Searches: 2
          ->  Index Scan using tprt4_idx on tprt_4 (never executed)
                Index Cond: (col1 < tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt5_idx on tprt_5 (never executed)
                Index Cond: (col1 < tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt6_idx on tprt_6 (never executed)
                Index Cond: (col1 < tbl1.col1)
-(15 rows)
+               Index Searches: 0
+(21 rows)
 
 explain (analyze, costs off, summary off, timing off, buffers off)
 select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
@@ -3077,17 +3120,23 @@ select * from tbl1 inner join tprt on tbl1.col1 = tprt.col1;
    ->  Append (actual rows=0.60 loops=5)
          ->  Index Scan using tprt1_idx on tprt_1 (never executed)
                Index Cond: (col1 = tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt2_idx on tprt_2 (actual rows=1.00 loops=2)
                Index Cond: (col1 = tbl1.col1)
+               Index Searches: 2
          ->  Index Scan using tprt3_idx on tprt_3 (actual rows=0.33 loops=3)
                Index Cond: (col1 = tbl1.col1)
+               Index Searches: 3
          ->  Index Scan using tprt4_idx on tprt_4 (never executed)
                Index Cond: (col1 = tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt5_idx on tprt_5 (never executed)
                Index Cond: (col1 = tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt6_idx on tprt_6 (never executed)
                Index Cond: (col1 = tbl1.col1)
-(15 rows)
+               Index Searches: 0
+(21 rows)
 
 select tbl1.col1, tprt.col1 from tbl1
 inner join tprt on tbl1.col1 > tprt.col1
@@ -3141,17 +3190,23 @@ select * from tbl1 join tprt on tbl1.col1 < tprt.col1;
    ->  Append (actual rows=1.00 loops=1)
          ->  Index Scan using tprt1_idx on tprt_1 (never executed)
                Index Cond: (col1 > tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt2_idx on tprt_2 (never executed)
                Index Cond: (col1 > tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt3_idx on tprt_3 (never executed)
                Index Cond: (col1 > tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt4_idx on tprt_4 (never executed)
                Index Cond: (col1 > tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt5_idx on tprt_5 (never executed)
                Index Cond: (col1 > tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt6_idx on tprt_6 (actual rows=1.00 loops=1)
                Index Cond: (col1 > tbl1.col1)
-(15 rows)
+               Index Searches: 1
+(21 rows)
 
 select tbl1.col1, tprt.col1 from tbl1
 inner join tprt on tbl1.col1 < tprt.col1
@@ -3173,17 +3228,23 @@ select * from tbl1 join tprt on tbl1.col1 = tprt.col1;
    ->  Append (actual rows=0.00 loops=1)
          ->  Index Scan using tprt1_idx on tprt_1 (never executed)
                Index Cond: (col1 = tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt2_idx on tprt_2 (never executed)
                Index Cond: (col1 = tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt3_idx on tprt_3 (never executed)
                Index Cond: (col1 = tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt4_idx on tprt_4 (never executed)
                Index Cond: (col1 = tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt5_idx on tprt_5 (never executed)
                Index Cond: (col1 = tbl1.col1)
+               Index Searches: 0
          ->  Index Scan using tprt6_idx on tprt_6 (never executed)
                Index Cond: (col1 = tbl1.col1)
-(15 rows)
+               Index Searches: 0
+(21 rows)
 
 select tbl1.col1, tprt.col1 from tbl1
 inner join tprt on tbl1.col1 = tprt.col1
@@ -3513,10 +3574,12 @@ explain (analyze, costs off, summary off, timing off, buffers off) execute mt_q1
    ->  Index Scan using ma_test_p2_b_idx on ma_test_p2 ma_test_1 (actual rows=1.00 loops=1)
          Filter: ((a >= $1) AND ((a % 10) = 5))
          Rows Removed by Filter: 9
+         Index Searches: 1
    ->  Index Scan using ma_test_p3_b_idx on ma_test_p3 ma_test_2 (actual rows=1.00 loops=1)
          Filter: ((a >= $1) AND ((a % 10) = 5))
          Rows Removed by Filter: 9
-(9 rows)
+         Index Searches: 1
+(11 rows)
 
 execute mt_q1(15);
  a  
@@ -3534,7 +3597,8 @@ explain (analyze, costs off, summary off, timing off, buffers off) execute mt_q1
    ->  Index Scan using ma_test_p3_b_idx on ma_test_p3 ma_test_1 (actual rows=1.00 loops=1)
          Filter: ((a >= $1) AND ((a % 10) = 5))
          Rows Removed by Filter: 9
-(6 rows)
+         Index Searches: 1
+(7 rows)
 
 execute mt_q1(25);
  a  
@@ -3582,13 +3646,17 @@ explain (analyze, costs off, summary off, timing off, buffers off) select * from
              ->  Limit (actual rows=1.00 loops=1)
                    ->  Index Scan using ma_test_p2_b_idx on ma_test_p2 (actual rows=1.00 loops=1)
                          Index Cond: (b IS NOT NULL)
+                         Index Searches: 1
    ->  Index Scan using ma_test_p1_b_idx on ma_test_p1 ma_test_1 (never executed)
          Filter: (a >= (InitPlan 2).col1)
+         Index Searches: 0
    ->  Index Scan using ma_test_p2_b_idx on ma_test_p2 ma_test_2 (actual rows=10.00 loops=1)
          Filter: (a >= (InitPlan 2).col1)
+         Index Searches: 1
    ->  Index Scan using ma_test_p3_b_idx on ma_test_p3 ma_test_3 (actual rows=10.00 loops=1)
          Filter: (a >= (InitPlan 2).col1)
-(14 rows)
+         Index Searches: 1
+(18 rows)
 
 reset enable_seqscan;
 reset enable_sort;
@@ -4159,13 +4227,17 @@ select * from rangep where b IN((select 1),(select 2)) order by a;
          Sort Key: rangep_2.a
          ->  Index Scan using rangep_0_to_100_1_a_idx on rangep_0_to_100_1 rangep_2 (actual rows=0.00 loops=1)
                Filter: (b = ANY (ARRAY[(InitPlan 1).col1, (InitPlan 2).col1]))
+               Index Searches: 1
          ->  Index Scan using rangep_0_to_100_2_a_idx on rangep_0_to_100_2 rangep_3 (actual rows=0.00 loops=1)
                Filter: (b = ANY (ARRAY[(InitPlan 1).col1, (InitPlan 2).col1]))
+               Index Searches: 1
          ->  Index Scan using rangep_0_to_100_3_a_idx on rangep_0_to_100_3 rangep_4 (never executed)
                Filter: (b = ANY (ARRAY[(InitPlan 1).col1, (InitPlan 2).col1]))
+               Index Searches: 0
    ->  Index Scan using rangep_100_to_200_a_idx on rangep_100_to_200 rangep_5 (actual rows=0.00 loops=1)
          Filter: (b = ANY (ARRAY[(InitPlan 1).col1, (InitPlan 2).col1]))
-(15 rows)
+         Index Searches: 1
+(19 rows)
 
 reset enable_sort;
 drop table rangep;
diff --git a/src/test/regress/expected/select.out b/src/test/regress/expected/select.out
index cd79abc35db..bab0cc93ff5 100644
--- a/src/test/regress/expected/select.out
+++ b/src/test/regress/expected/select.out
@@ -764,7 +764,8 @@ select * from onek2 where unique2 = 11 and stringu1 = 'ATAAAA';
  Index Scan using onek2_u2_prtl on onek2 (actual rows=1.00 loops=1)
    Index Cond: (unique2 = 11)
    Filter: (stringu1 = 'ATAAAA'::name)
-(3 rows)
+   Index Searches: 1
+(4 rows)
 
 explain (costs off)
 select unique2 from onek2 where unique2 = 11 and stringu1 = 'ATAAAA';
diff --git a/src/test/regress/sql/memoize.sql b/src/test/regress/sql/memoize.sql
index d5aab4e5666..c0d47fa875a 100644
--- a/src/test/regress/sql/memoize.sql
+++ b/src/test/regress/sql/memoize.sql
@@ -23,8 +23,9 @@ begin
         ln := regexp_replace(ln, 'Evictions: 0', 'Evictions: Zero');
         ln := regexp_replace(ln, 'Evictions: \d+', 'Evictions: N');
         ln := regexp_replace(ln, 'Memory Usage: \d+', 'Memory Usage: N');
-	ln := regexp_replace(ln, 'Heap Fetches: \d+', 'Heap Fetches: N');
-	ln := regexp_replace(ln, 'loops=\d+', 'loops=N');
+        ln := regexp_replace(ln, 'Heap Fetches: \d+', 'Heap Fetches: N');
+        ln := regexp_replace(ln, 'loops=\d+', 'loops=N');
+        ln := regexp_replace(ln, 'Index Searches: \d+', 'Index Searches: N');
         return next ln;
     end loop;
 end;
diff --git a/src/test/regress/sql/partition_prune.sql b/src/test/regress/sql/partition_prune.sql
index 5f36d589b6b..4a2c74b0899 100644
--- a/src/test/regress/sql/partition_prune.sql
+++ b/src/test/regress/sql/partition_prune.sql
@@ -588,6 +588,10 @@ begin
         ln := regexp_replace(ln, 'Workers Launched: \d+', 'Workers Launched: N');
         ln := regexp_replace(ln, 'actual rows=\d+(?:\.\d+)? loops=\d+', 'actual rows=N loops=N');
         ln := regexp_replace(ln, 'Rows Removed by Filter: \d+', 'Rows Removed by Filter: N');
+        perform regexp_matches(ln, 'Index Searches: \d+');
+        if found then
+          continue;
+        end if;
         return next ln;
     end loop;
 end;