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674899ae02
Commit ce77abe63c allowed EXPLAIN (BUFFERS) to report the information
on buffer usage during planning phase. However three issues were
reported regarding this feature.
(1) Previously, EXPLAIN option BUFFERS required ANALYZE. So the query
had to be actually executed by specifying ANALYZE even when we
want to see only the planner's buffer usage. This was inconvenient
especially when the query was write one like DELETE.
(2) EXPLAIN included the planner's buffer usage in summary
information. So SUMMARY option had to be enabled to report that.
Also this format was confusing.
(3) The output structure for planning information was not consistent
between TEXT format and the others. For example, "Planning" tag
was output in JSON format, but not in TEXT format.
For (1), this commit allows us to perform EXPLAIN (BUFFERS) without
ANALYZE to report the planner's buffer usage.
For (2), this commit changed EXPLAIN output so that the planner's
buffer usage is reported before summary information.
For (3), this commit made the output structure for planning
information more consistent between the formats.
Back-patch to v13 where the planner's buffer usage was allowed to
be reported in EXPLAIN.
Reported-by: Pierre Giraud, David Rowley
Author: Fujii Masao
Reviewed-by: David Rowley, Julien Rouhaud, Pierre Giraud
Discussion: https://postgr.es/m/07b226e6-fa49-687f-b110-b7c37572f69e@dalibo.com
471 lines
21 KiB
Text
471 lines
21 KiB
Text
--
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-- EXPLAIN
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--
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-- There are many test cases elsewhere that use EXPLAIN as a vehicle for
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-- checking something else (usually planner behavior). This file is
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-- concerned with testing EXPLAIN in its own right.
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--
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-- To produce stable regression test output, it's usually necessary to
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-- ignore details such as exact costs or row counts. These filter
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-- functions replace changeable output details with fixed strings.
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create function explain_filter(text) returns setof text
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language plpgsql as
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$$
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declare
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ln text;
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begin
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for ln in execute $1
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loop
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-- Replace any numeric word with just 'N'
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ln := regexp_replace(ln, '\m\d+\M', 'N', 'g');
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-- In sort output, the above won't match units-suffixed numbers
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ln := regexp_replace(ln, '\m\d+kB', 'NkB', 'g');
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-- Ignore text-mode buffers output because it varies depending
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-- on the system state
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CONTINUE WHEN (ln ~ ' +Buffers: .*');
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return next ln;
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end loop;
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end;
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$$;
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-- To produce valid JSON output, replace numbers with "0" or "0.0" not "N"
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create function explain_filter_to_json(text) returns jsonb
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language plpgsql as
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$$
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declare
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data text := '';
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ln text;
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begin
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for ln in execute $1
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loop
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-- Replace any numeric word with just '0'
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ln := regexp_replace(ln, '\m\d+\M', '0', 'g');
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data := data || ln;
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end loop;
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return data::jsonb;
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end;
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$$;
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-- Simple cases
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select explain_filter('explain select * from int8_tbl i8');
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explain_filter
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---------------------------------------------------------
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Seq Scan on int8_tbl i8 (cost=N.N..N.N rows=N width=N)
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(1 row)
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select explain_filter('explain (analyze) select * from int8_tbl i8');
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explain_filter
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-----------------------------------------------------------------------------------------------
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Seq Scan on int8_tbl i8 (cost=N.N..N.N rows=N width=N) (actual time=N.N..N.N rows=N loops=N)
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Planning Time: N.N ms
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Execution Time: N.N ms
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(3 rows)
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select explain_filter('explain (analyze, verbose) select * from int8_tbl i8');
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explain_filter
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------------------------------------------------------------------------------------------------------
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Seq Scan on public.int8_tbl i8 (cost=N.N..N.N rows=N width=N) (actual time=N.N..N.N rows=N loops=N)
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Output: q1, q2
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Planning Time: N.N ms
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Execution Time: N.N ms
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(4 rows)
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select explain_filter('explain (analyze, buffers, format text) select * from int8_tbl i8');
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explain_filter
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-----------------------------------------------------------------------------------------------
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Seq Scan on int8_tbl i8 (cost=N.N..N.N rows=N width=N) (actual time=N.N..N.N rows=N loops=N)
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Planning Time: N.N ms
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Execution Time: N.N ms
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(3 rows)
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select explain_filter('explain (analyze, buffers, format json) select * from int8_tbl i8');
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explain_filter
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------------------------------------
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[ +
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{ +
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"Plan": { +
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"Node Type": "Seq Scan", +
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"Parallel Aware": false, +
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"Relation Name": "int8_tbl",+
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"Alias": "i8", +
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"Startup Cost": N.N, +
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"Total Cost": N.N, +
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"Plan Rows": N, +
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"Plan Width": N, +
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"Actual Startup Time": N.N, +
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"Actual Total Time": N.N, +
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"Actual Rows": N, +
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"Actual Loops": N, +
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"Shared Hit Blocks": N, +
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"Shared Read Blocks": N, +
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"Shared Dirtied Blocks": N, +
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"Shared Written Blocks": N, +
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"Local Hit Blocks": N, +
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"Local Read Blocks": N, +
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"Local Dirtied Blocks": N, +
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"Local Written Blocks": N, +
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"Temp Read Blocks": N, +
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"Temp Written Blocks": N +
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}, +
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"Planning": { +
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"Shared Hit Blocks": N, +
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"Shared Read Blocks": N, +
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"Shared Dirtied Blocks": N, +
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"Shared Written Blocks": N, +
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"Local Hit Blocks": N, +
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"Local Read Blocks": N, +
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"Local Dirtied Blocks": N, +
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"Local Written Blocks": N, +
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"Temp Read Blocks": N, +
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"Temp Written Blocks": N +
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}, +
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"Planning Time": N.N, +
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"Triggers": [ +
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], +
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"Execution Time": N.N +
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} +
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]
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(1 row)
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select explain_filter('explain (analyze, buffers, format xml) select * from int8_tbl i8');
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explain_filter
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--------------------------------------------------------
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<explain xmlns="http://www.postgresql.org/N/explain"> +
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<Query> +
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<Plan> +
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<Node-Type>Seq Scan</Node-Type> +
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<Parallel-Aware>false</Parallel-Aware> +
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<Relation-Name>int8_tbl</Relation-Name> +
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<Alias>i8</Alias> +
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<Startup-Cost>N.N</Startup-Cost> +
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<Total-Cost>N.N</Total-Cost> +
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<Plan-Rows>N</Plan-Rows> +
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<Plan-Width>N</Plan-Width> +
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<Actual-Startup-Time>N.N</Actual-Startup-Time> +
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<Actual-Total-Time>N.N</Actual-Total-Time> +
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<Actual-Rows>N</Actual-Rows> +
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<Actual-Loops>N</Actual-Loops> +
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<Shared-Hit-Blocks>N</Shared-Hit-Blocks> +
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<Shared-Read-Blocks>N</Shared-Read-Blocks> +
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<Shared-Dirtied-Blocks>N</Shared-Dirtied-Blocks>+
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<Shared-Written-Blocks>N</Shared-Written-Blocks>+
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<Local-Hit-Blocks>N</Local-Hit-Blocks> +
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<Local-Read-Blocks>N</Local-Read-Blocks> +
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<Local-Dirtied-Blocks>N</Local-Dirtied-Blocks> +
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<Local-Written-Blocks>N</Local-Written-Blocks> +
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<Temp-Read-Blocks>N</Temp-Read-Blocks> +
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<Temp-Written-Blocks>N</Temp-Written-Blocks> +
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</Plan> +
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<Planning> +
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<Shared-Hit-Blocks>N</Shared-Hit-Blocks> +
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<Shared-Read-Blocks>N</Shared-Read-Blocks> +
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<Shared-Dirtied-Blocks>N</Shared-Dirtied-Blocks>+
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<Shared-Written-Blocks>N</Shared-Written-Blocks>+
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<Local-Hit-Blocks>N</Local-Hit-Blocks> +
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<Local-Read-Blocks>N</Local-Read-Blocks> +
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<Local-Dirtied-Blocks>N</Local-Dirtied-Blocks> +
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<Local-Written-Blocks>N</Local-Written-Blocks> +
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<Temp-Read-Blocks>N</Temp-Read-Blocks> +
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<Temp-Written-Blocks>N</Temp-Written-Blocks> +
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</Planning> +
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<Planning-Time>N.N</Planning-Time> +
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<Triggers> +
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</Triggers> +
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<Execution-Time>N.N</Execution-Time> +
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</Query> +
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</explain>
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(1 row)
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select explain_filter('explain (analyze, buffers, format yaml) select * from int8_tbl i8');
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explain_filter
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-------------------------------
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- Plan: +
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Node Type: "Seq Scan" +
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Parallel Aware: false +
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Relation Name: "int8_tbl"+
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Alias: "i8" +
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Startup Cost: N.N +
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Total Cost: N.N +
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Plan Rows: N +
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Plan Width: N +
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Actual Startup Time: N.N +
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Actual Total Time: N.N +
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Actual Rows: N +
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Actual Loops: N +
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Shared Hit Blocks: N +
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Shared Read Blocks: N +
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Shared Dirtied Blocks: N +
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Shared Written Blocks: N +
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Local Hit Blocks: N +
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Local Read Blocks: N +
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Local Dirtied Blocks: N +
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Local Written Blocks: N +
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Temp Read Blocks: N +
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Temp Written Blocks: N +
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Planning: +
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Shared Hit Blocks: N +
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Shared Read Blocks: N +
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Shared Dirtied Blocks: N +
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Shared Written Blocks: N +
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Local Hit Blocks: N +
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Local Read Blocks: N +
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Local Dirtied Blocks: N +
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Local Written Blocks: N +
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Temp Read Blocks: N +
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Temp Written Blocks: N +
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Planning Time: N.N +
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Triggers: +
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Execution Time: N.N
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(1 row)
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select explain_filter('explain (buffers, format text) select * from int8_tbl i8');
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explain_filter
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---------------------------------------------------------
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Seq Scan on int8_tbl i8 (cost=N.N..N.N rows=N width=N)
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(1 row)
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select explain_filter('explain (buffers, format json) select * from int8_tbl i8');
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explain_filter
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------------------------------------
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[ +
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{ +
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"Plan": { +
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"Node Type": "Seq Scan", +
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"Parallel Aware": false, +
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"Relation Name": "int8_tbl",+
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"Alias": "i8", +
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"Startup Cost": N.N, +
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"Total Cost": N.N, +
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"Plan Rows": N, +
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"Plan Width": N, +
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"Shared Hit Blocks": N, +
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"Shared Read Blocks": N, +
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"Shared Dirtied Blocks": N, +
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"Shared Written Blocks": N, +
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"Local Hit Blocks": N, +
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"Local Read Blocks": N, +
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"Local Dirtied Blocks": N, +
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"Local Written Blocks": N, +
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"Temp Read Blocks": N, +
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"Temp Written Blocks": N +
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}, +
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"Planning": { +
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"Shared Hit Blocks": N, +
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"Shared Read Blocks": N, +
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"Shared Dirtied Blocks": N, +
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"Shared Written Blocks": N, +
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"Local Hit Blocks": N, +
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"Local Read Blocks": N, +
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"Local Dirtied Blocks": N, +
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"Local Written Blocks": N, +
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"Temp Read Blocks": N, +
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"Temp Written Blocks": N +
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} +
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} +
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]
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(1 row)
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-- SETTINGS option
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-- We have to ignore other settings that might be imposed by the environment,
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-- so printing the whole Settings field unfortunately won't do.
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begin;
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set local plan_cache_mode = force_generic_plan;
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select true as "OK"
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from explain_filter('explain (settings) select * from int8_tbl i8') ln
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where ln ~ '^ *Settings: .*plan_cache_mode = ''force_generic_plan''';
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OK
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----
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t
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(1 row)
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select explain_filter_to_json('explain (settings, format json) select * from int8_tbl i8') #> '{0,Settings,plan_cache_mode}';
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?column?
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----------------------
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"force_generic_plan"
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(1 row)
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rollback;
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--
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-- Test production of per-worker data
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--
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-- Unfortunately, because we don't know how many worker processes we'll
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-- actually get (maybe none at all), we can't examine the "Workers" output
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-- in any detail. We can check that it parses correctly as JSON, and then
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-- remove it from the displayed results.
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-- Serializable isolation would disable parallel query, so explicitly use an
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-- arbitrary other level.
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begin isolation level repeatable read;
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-- encourage use of parallel plans
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set parallel_setup_cost=0;
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set parallel_tuple_cost=0;
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set min_parallel_table_scan_size=0;
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set max_parallel_workers_per_gather=4;
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select jsonb_pretty(
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explain_filter_to_json('explain (analyze, verbose, buffers, format json)
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select * from tenk1 order by tenthous')
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-- remove "Workers" node of the Seq Scan plan node
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#- '{0,Plan,Plans,0,Plans,0,Workers}'
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-- remove "Workers" node of the Sort plan node
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#- '{0,Plan,Plans,0,Workers}'
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-- Also remove its sort-type fields, as those aren't 100% stable
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#- '{0,Plan,Plans,0,Sort Method}'
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#- '{0,Plan,Plans,0,Sort Space Type}'
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);
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jsonb_pretty
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-------------------------------------------------------------
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[ +
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{ +
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"Plan": { +
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"Plans": [ +
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{ +
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"Plans": [ +
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{ +
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"Alias": "tenk1", +
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"Output": [ +
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"unique1", +
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"unique2", +
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"two", +
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"four", +
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"ten", +
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"twenty", +
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"hundred", +
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"thousand", +
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"twothousand", +
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"fivethous", +
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"tenthous", +
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"odd", +
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"even", +
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"stringu1", +
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"stringu2", +
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"string4" +
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], +
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"Schema": "public", +
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"Node Type": "Seq Scan", +
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"Plan Rows": 0, +
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"Plan Width": 0, +
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"Total Cost": 0.0, +
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"Actual Rows": 0, +
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"Actual Loops": 0, +
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"Startup Cost": 0.0, +
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"Relation Name": "tenk1", +
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"Parallel Aware": true, +
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"Local Hit Blocks": 0, +
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"Temp Read Blocks": 0, +
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"Actual Total Time": 0.0, +
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"Local Read Blocks": 0, +
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"Shared Hit Blocks": 0, +
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"Shared Read Blocks": 0, +
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"Actual Startup Time": 0.0, +
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"Parent Relationship": "Outer",+
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"Temp Written Blocks": 0, +
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"Local Dirtied Blocks": 0, +
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"Local Written Blocks": 0, +
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"Shared Dirtied Blocks": 0, +
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"Shared Written Blocks": 0 +
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} +
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], +
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"Output": [ +
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"unique1", +
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"unique2", +
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"two", +
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"four", +
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"ten", +
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"twenty", +
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"hundred", +
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"thousand", +
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"twothousand", +
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"fivethous", +
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"tenthous", +
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"odd", +
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"even", +
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"stringu1", +
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"stringu2", +
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"string4" +
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], +
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"Sort Key": [ +
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"tenk1.tenthous" +
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], +
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"Node Type": "Sort", +
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"Plan Rows": 0, +
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"Plan Width": 0, +
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"Total Cost": 0.0, +
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"Actual Rows": 0, +
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"Actual Loops": 0, +
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"Startup Cost": 0.0, +
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"Parallel Aware": false, +
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"Sort Space Used": 0, +
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"Local Hit Blocks": 0, +
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"Temp Read Blocks": 0, +
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"Actual Total Time": 0.0, +
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"Local Read Blocks": 0, +
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"Shared Hit Blocks": 0, +
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"Shared Read Blocks": 0, +
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"Actual Startup Time": 0.0, +
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"Parent Relationship": "Outer", +
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"Temp Written Blocks": 0, +
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"Local Dirtied Blocks": 0, +
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"Local Written Blocks": 0, +
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"Shared Dirtied Blocks": 0, +
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"Shared Written Blocks": 0 +
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} +
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], +
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"Output": [ +
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"unique1", +
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"unique2", +
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"two", +
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"four", +
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"ten", +
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"twenty", +
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"hundred", +
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"thousand", +
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"twothousand", +
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"fivethous", +
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"tenthous", +
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"odd", +
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"even", +
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"stringu1", +
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"stringu2", +
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"string4" +
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], +
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"Node Type": "Gather Merge", +
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"Plan Rows": 0, +
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"Plan Width": 0, +
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"Total Cost": 0.0, +
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"Actual Rows": 0, +
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"Actual Loops": 0, +
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"Startup Cost": 0.0, +
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"Parallel Aware": false, +
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"Workers Planned": 0, +
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"Local Hit Blocks": 0, +
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"Temp Read Blocks": 0, +
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"Workers Launched": 0, +
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"Actual Total Time": 0.0, +
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"Local Read Blocks": 0, +
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"Shared Hit Blocks": 0, +
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"Shared Read Blocks": 0, +
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"Actual Startup Time": 0.0, +
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"Temp Written Blocks": 0, +
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"Local Dirtied Blocks": 0, +
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"Local Written Blocks": 0, +
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"Shared Dirtied Blocks": 0, +
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"Shared Written Blocks": 0 +
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}, +
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"Planning": { +
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"Local Hit Blocks": 0, +
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"Temp Read Blocks": 0, +
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"Local Read Blocks": 0, +
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"Shared Hit Blocks": 0, +
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"Shared Read Blocks": 0, +
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"Temp Written Blocks": 0, +
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"Local Dirtied Blocks": 0, +
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"Local Written Blocks": 0, +
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"Shared Dirtied Blocks": 0, +
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"Shared Written Blocks": 0 +
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}, +
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"Triggers": [ +
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], +
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"Planning Time": 0.0, +
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"Execution Time": 0.0 +
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} +
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]
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(1 row)
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rollback;
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