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diff --git a/src/test/regress/sql/explain.sql b/src/test/regress/sql/explain.sql
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+--
+-- EXPLAIN
+--
+-- There are many test cases elsewhere that use EXPLAIN as a vehicle for
+-- checking something else (usually planner behavior).  This file is
+-- concerned with testing EXPLAIN in its own right.
+--
+
+-- To produce stable regression test output, it's usually necessary to
+-- ignore details such as exact costs or row counts.  These filter
+-- functions replace changeable output details with fixed strings.
+
+create function explain_filter(text) returns setof text
+language plpgsql as
+$$
+declare
+    ln text;
+begin
+    for ln in execute $1
+    loop
+        -- Replace any numeric word with just 'N'
+        ln := regexp_replace(ln, '-?\m\d+\M', 'N', 'g');
+        -- In sort output, the above won't match units-suffixed numbers
+        ln := regexp_replace(ln, '\m\d+kB', 'NkB', 'g');
+        -- Ignore text-mode buffers output because it varies depending
+        -- on the system state
+        CONTINUE WHEN (ln ~ ' +Buffers: .*');
+        -- Ignore text-mode "Planning:" line because whether it's output
+        -- varies depending on the system state
+        CONTINUE WHEN (ln = 'Planning:');
+        return next ln;
+    end loop;
+end;
+$$;
+
+-- To produce valid JSON output, replace numbers with "0" or "0.0" not "N"
+create function explain_filter_to_json(text) returns jsonb
+language plpgsql as
+$$
+declare
+    data text := '';
+    ln text;
+begin
+    for ln in execute $1
+    loop
+        -- Replace any numeric word with just '0'
+        ln := regexp_replace(ln, '\m\d+\M', '0', 'g');
+        data := data || ln;
+    end loop;
+    return data::jsonb;
+end;
+$$;
+
+-- Simple cases
+
+select explain_filter('explain select * from int8_tbl i8');
+select explain_filter('explain (analyze) select * from int8_tbl i8');
+select explain_filter('explain (analyze, verbose) select * from int8_tbl i8');
+select explain_filter('explain (analyze, buffers, format text) select * from int8_tbl i8');
+select explain_filter('explain (analyze, buffers, format json) select * from int8_tbl i8');
+select explain_filter('explain (analyze, buffers, format xml) select * from int8_tbl i8');
+select explain_filter('explain (analyze, buffers, format yaml) select * from int8_tbl i8');
+select explain_filter('explain (buffers, format text) select * from int8_tbl i8');
+select explain_filter('explain (buffers, format json) select * from int8_tbl i8');
+
+-- SETTINGS option
+-- We have to ignore other settings that might be imposed by the environment,
+-- so printing the whole Settings field unfortunately won't do.
+
+begin;
+set local plan_cache_mode = force_generic_plan;
+select true as "OK"
+  from explain_filter('explain (settings) select * from int8_tbl i8') ln
+  where ln ~ '^ *Settings: .*plan_cache_mode = ''force_generic_plan''';
+select explain_filter_to_json('explain (settings, format json) select * from int8_tbl i8') #> '{0,Settings,plan_cache_mode}';
+rollback;
+
+--
+-- Test production of per-worker data
+--
+-- Unfortunately, because we don't know how many worker processes we'll
+-- actually get (maybe none at all), we can't examine the "Workers" output
+-- in any detail.  We can check that it parses correctly as JSON, and then
+-- remove it from the displayed results.
+
+begin;
+-- encourage use of parallel plans
+set parallel_setup_cost=0;
+set parallel_tuple_cost=0;
+set min_parallel_table_scan_size=0;
+set max_parallel_workers_per_gather=4;
+
+select jsonb_pretty(
+  explain_filter_to_json('explain (analyze, verbose, buffers, format json)
+                         select * from tenk1 order by tenthous')
+  -- remove "Workers" node of the Seq Scan plan node
+  #- '{0,Plan,Plans,0,Plans,0,Workers}'
+  -- remove "Workers" node of the Sort plan node
+  #- '{0,Plan,Plans,0,Workers}'
+  -- Also remove its sort-type fields, as those aren't 100% stable
+  #- '{0,Plan,Plans,0,Sort Method}'
+  #- '{0,Plan,Plans,0,Sort Space Type}'
+);
+
+rollback;
+
+set compute_query_id = on;
+select explain_filter('explain (verbose) select * from int8_tbl i8');