> On Sat, Dec 26, 2020 at 08:53:28AM -0800, Zhihong Yu wrote:
> Hi,
> A few comments.
>
> + foreach(lc, (List *) expr)
> + {
> + Node * subExpr = (Node *) lfirst(lc);
> +
> + if (!IsA(subExpr, Const))
> + {
> + allConst = false;
> + break;
> + }
> + }
>
> It seems the above foreach loop (within foreach(temp, (List *) node)) can
> be preceded with a check that allConst is true. Otherwise the loop can be
> skipped.
Thanks for noticing. Now that I look at it closer I think it's the other
way around, the loop above checking constants for the first expression
is not really necessary.
> + if (currentExprIdx == pgss_merge_threshold - 1)
> + {
> + JumbleExpr(jstate, expr);
> +
> + /*
> + * A const expr is already found, so JumbleExpr must
> + * record it. Mark it as merged, it will be the
> first
> + * merged but still present in the statement query.
> + */
> + Assert(jstate->clocations_count > 0);
> + jstate->clocations[jstate->clocations_count -
> 1].merged = true;
> + currentExprIdx++;
> + }
>
> The above snippet occurs a few times. Maybe extract into a helper method.
Originally I was hesitant to extract it was because it's quite small
part of the code. But now I've realized that the part relevant to lists
is not really correct, which makes those bits even more different, so I
think it makes sense to leave it like that. What do you think?
>From 35f3355e56462773263d31bebaf60fee6a71dca5 Mon Sep 17 00:00:00 2001
From: Dmitrii Dolgov <9erthali...@gmail.com>
Date: Tue, 17 Nov 2020 16:18:08 +0100
Subject: [PATCH v3] Prevent jumbling of every element in ArrayExpr
pg_stat_statements produces multiple entries for queries like
SELECT something FROM table WHERE col IN (1, 2, 3, ...)
depending on number of parameters, because every element of ArrayExpr is
jumbled. Make Consts contribute nothing to the jumble hash if they're
part of a series and at position further that specified threshold. Do
the same for similar queries with VALUES as well.
---
.../expected/pg_stat_statements.out | 750 +++++++++++++++++-
.../pg_stat_statements/pg_stat_statements.c | 262 +++++-
.../sql/pg_stat_statements.sql | 139 ++++
3 files changed, 1137 insertions(+), 14 deletions(-)
diff --git a/contrib/pg_stat_statements/expected/pg_stat_statements.out b/contrib/pg_stat_statements/expected/pg_stat_statements.out
index 2a303a7f07..4b5ed40bb2 100644
--- a/contrib/pg_stat_statements/expected/pg_stat_statements.out
+++ b/contrib/pg_stat_statements/expected/pg_stat_statements.out
@@ -205,7 +205,7 @@ SELECT query, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C";
INSERT INTO test VALUES(generate_series($1, $2), $3) | 1 | 10
SELECT * FROM test ORDER BY a | 1 | 12
SELECT * FROM test WHERE a > $1 ORDER BY a | 2 | 4
- SELECT * FROM test WHERE a IN ($1, $2, $3, $4, $5) | 1 | 8
+ SELECT * FROM test WHERE a IN ($1, $2, $3, $4, ...) | 1 | 8
SELECT pg_stat_statements_reset() | 1 | 1
SELECT query, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C" | 0 | 0
UPDATE test SET b = $1 WHERE a = $2 | 6 | 6
@@ -861,4 +861,752 @@ SELECT query, plans, calls, rows FROM pg_stat_statements ORDER BY query COLLATE
SELECT query, plans, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C" | 1 | 0 | 0
(6 rows)
+--
+-- Consts merging
+--
+SET pg_stat_statements.merge_threshold = 5;
+CREATE TABLE test_merge (id int, data int);
+-- IN queries
+-- Normal
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3);
+ id | data
+----+------
+(0 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3) | 1
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 0
+(3 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6);
+ id | data
+----+------
+(0 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7);
+ id | data
+----+------
+(0 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8);
+ id | data
+----+------
+(0 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9);
+ id | data
+----+------
+(0 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+ id | data
+----+------
+(0 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3) | 1
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4, ...) | 5
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 1
+(4 rows)
+
+-- On the merge threshold
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4);
+ id | data
+----+------
+(0 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4) | 1
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 0
+(3 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5);
+ id | data
+----+------
+(0 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6);
+ id | data
+----+------
+(0 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7);
+ id | data
+----+------
+(0 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8);
+ id | data
+----+------
+(0 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9);
+ id | data
+----+------
+(0 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+ id | data
+----+------
+(0 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4) | 1
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4, ...) | 6
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 1
+(4 rows)
+
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5);
+ id | data
+----+------
+(0 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4, ...) | 1
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 0
+(3 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6);
+ id | data
+----+------
+(0 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7);
+ id | data
+----+------
+(0 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8);
+ id | data
+----+------
+(0 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9);
+ id | data
+----+------
+(0 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+ id | data
+----+------
+(0 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4, ...) | 6
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 1
+(3 rows)
+
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6);
+ id | data
+----+------
+(0 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4, ...) | 1
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 0
+(3 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7);
+ id | data
+----+------
+(0 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8);
+ id | data
+----+------
+(0 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9);
+ id | data
+----+------
+(0 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+ id | data
+----+------
+(0 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4, ...) | 5
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 1
+(3 rows)
+
+-- With gaps on the threshold
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4);
+ id | data
+----+------
+(0 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4) | 1
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 0
+(3 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+ id | data
+----+------
+(0 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4) | 1
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4, ...) | 1
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 1
+(4 rows)
+
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5);
+ id | data
+----+------
+(0 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4, ...) | 1
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 0
+(3 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+ id | data
+----+------
+(0 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4, ...) | 2
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 1
+(3 rows)
+
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6);
+ id | data
+----+------
+(0 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4, ...) | 1
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 0
+(3 rows)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+ id | data
+----+------
+(0 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4, ...) | 2
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 1
+(3 rows)
+
+-- test constants after merge
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) and data = 2;
+ id | data
+----+------
+(0 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+---------------------------------------------------------------------------+-------
+ SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4, ...) and data = $11 | 1
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 0
+(3 rows)
+
+-- test prepared statement
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+PREPARE query AS
+SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10);
+EXECUTE query (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+ id | data
+----+------
+(0 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ PREPARE query AS +| 1
+ SELECT * FROM test_merge WHERE id IN ($6, $7, $8, ...) |
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 0
+(3 rows)
+
+-- VALUES queries
+-- Normal
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT * FROM (VALUES (1), (2), (3)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+(3 rows)
+
+SELECT * FROM (VALUES (1), (2), (3), (4)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+(4 rows)
+
+SELECT * FROM (VALUES (1), (2), (3), (4), (5)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+ 5
+(5 rows)
+
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+(6 rows)
+
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+(7 rows)
+
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7), (8)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+ 8
+(8 rows)
+
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7), (8), (9)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+ 8
+ 9
+(9 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM (VALUES ($1), ($2), ($3)) q | 1
+ SELECT * FROM (VALUES ($1), ($2), ($3), ($4)) q | 1
+ SELECT * FROM (VALUES ($1), ($2), ($3), ($4), (...)) q | 5
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 0
+(5 rows)
+
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT * FROM (VALUES (1, 1), (2, 2), (3, 3)) q;
+ column1 | column2
+---------+---------
+ 1 | 1
+ 2 | 2
+ 3 | 3
+(3 rows)
+
+SELECT * FROM (VALUES (1, 1), (2, 2), (3, 3), (4, 4)) q;
+ column1 | column2
+---------+---------
+ 1 | 1
+ 2 | 2
+ 3 | 3
+ 4 | 4
+(4 rows)
+
+SELECT * FROM (VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5)) q;
+ column1 | column2
+---------+---------
+ 1 | 1
+ 2 | 2
+ 3 | 3
+ 4 | 4
+ 5 | 5
+(5 rows)
+
+SELECT * FROM (VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)) q;
+ column1 | column2
+---------+---------
+ 1 | 1
+ 2 | 2
+ 3 | 3
+ 4 | 4
+ 5 | 5
+ 6 | 6
+(6 rows)
+
+SELECT * FROM (VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6), (7, 7)) q;
+ column1 | column2
+---------+---------
+ 1 | 1
+ 2 | 2
+ 3 | 3
+ 4 | 4
+ 5 | 5
+ 6 | 6
+ 7 | 7
+(7 rows)
+
+SELECT * FROM (VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6), (7, 7), (8, 8)) q;
+ column1 | column2
+---------+---------
+ 1 | 1
+ 2 | 2
+ 3 | 3
+ 4 | 4
+ 5 | 5
+ 6 | 6
+ 7 | 7
+ 8 | 8
+(8 rows)
+
+SELECT * FROM (VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6), (7, 7), (8, 8), (9, 9)) q;
+ column1 | column2
+---------+---------
+ 1 | 1
+ 2 | 2
+ 3 | 3
+ 4 | 4
+ 5 | 5
+ 6 | 6
+ 7 | 7
+ 8 | 8
+ 9 | 9
+(9 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM (VALUES ($1, $2), ($3, $4), ($5, $6)) q | 1
+ SELECT * FROM (VALUES ($1, $2), ($3, $4), ($5, $6), ($7, $8)) q | 1
+ SELECT * FROM (VALUES ($1, $2), ($3, $4), ($5, $6), ($7, $8), (...)) q | 5
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 0
+(5 rows)
+
+-- On the merge threshold
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT * FROM (VALUES (1), (2), (3), (4)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+(4 rows)
+
+SELECT * FROM (VALUES (1), (2), (3), (4), (5)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+ 5
+(5 rows)
+
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+(6 rows)
+
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+(7 rows)
+
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7), (8)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+ 8
+(8 rows)
+
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7), (8), (9)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+ 8
+ 9
+(9 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM (VALUES ($1), ($2), ($3), ($4)) q | 1
+ SELECT * FROM (VALUES ($1), ($2), ($3), ($4), (...)) q | 5
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 0
+(4 rows)
+
+-- With gaps on the treshold
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT * FROM (VALUES (1), (2), (3), (4)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+(4 rows)
+
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7), (8), (9)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+ 8
+ 9
+(9 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM (VALUES ($1), ($2), ($3), ($4)) q | 1
+ SELECT * FROM (VALUES ($1), ($2), ($3), ($4), (...)) q | 1
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 0
+(4 rows)
+
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT * FROM (VALUES (1), (2), (3), (4), (5)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+ 5
+(5 rows)
+
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7), (8), (9)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+ 8
+ 9
+(9 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM (VALUES ($1), ($2), ($3), ($4), (...)) q | 2
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 0
+(3 rows)
+
+SELECT pg_stat_statements_reset();
+ pg_stat_statements_reset
+--------------------------
+
+(1 row)
+
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+(6 rows)
+
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7), (8), (9)) q;
+ column1
+---------
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+ 8
+ 9
+(9 rows)
+
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+ query | calls
+------------------------------------------------------------------------+-------
+ SELECT * FROM (VALUES ($1), ($2), ($3), ($4), (...)) q | 2
+ SELECT pg_stat_statements_reset() | 1
+ SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C" | 0
+(3 rows)
+
DROP EXTENSION pg_stat_statements;
diff --git a/contrib/pg_stat_statements/pg_stat_statements.c b/contrib/pg_stat_statements/pg_stat_statements.c
index dd963c4644..103ecb7c61 100644
--- a/contrib/pg_stat_statements/pg_stat_statements.c
+++ b/contrib/pg_stat_statements/pg_stat_statements.c
@@ -231,6 +231,8 @@ typedef struct pgssLocationLen
{
int location; /* start offset in query text */
int length; /* length in bytes, or -1 to ignore */
+ bool merged; /* whether or not the location was marked as
+ duplicate */
} pgssLocationLen;
/*
@@ -245,7 +247,10 @@ typedef struct pgssJumbleState
/* Number of bytes used in jumble[] */
Size jumble_len;
- /* Array of locations of constants that should be removed */
+ /*
+ * Array of locations of constants that should be removed, or parameters
+ * that are already replaced, but could be also processed to be merged
+ */
pgssLocationLen *clocations;
/* Allocated length of clocations array */
@@ -299,6 +304,7 @@ static const struct config_enum_entry track_options[] =
static int pgss_max; /* max # statements to track */
static int pgss_track; /* tracking level */
+static int pgss_merge_threshold; /* minumum number of consts for merge */
static bool pgss_track_utility; /* whether to track utility commands */
static bool pgss_track_planning; /* whether to track planning duration */
static bool pgss_save; /* whether to save stats across shutdown */
@@ -374,7 +380,9 @@ static void JumbleQuery(pgssJumbleState *jstate, Query *query);
static void JumbleRangeTable(pgssJumbleState *jstate, List *rtable);
static void JumbleRowMarks(pgssJumbleState *jstate, List *rowMarks);
static void JumbleExpr(pgssJumbleState *jstate, Node *node);
-static void RecordConstLocation(pgssJumbleState *jstate, int location);
+static bool JumbleExprList(pgssJumbleState *jstate, Node *node);
+static void RecordConstLocation(pgssJumbleState *jstate, int location,
+ bool merged);
static char *generate_normalized_query(pgssJumbleState *jstate, const char *query,
int query_loc, int *query_len_p);
static void fill_in_constant_lengths(pgssJumbleState *jstate, const char *query,
@@ -460,6 +468,19 @@ _PG_init(void)
NULL,
NULL);
+ DefineCustomIntVariable("pg_stat_statements.merge_threshold",
+ "After this number of duplicate constants start to merge them.",
+ NULL,
+ &pgss_merge_threshold,
+ 5,
+ 1,
+ INT_MAX,
+ PGC_SUSET,
+ 0,
+ NULL,
+ NULL,
+ NULL);
+
EmitWarningsOnPlaceholders("pg_stat_statements");
/*
@@ -863,7 +884,7 @@ pgss_post_parse_analyze(ParseState *pstate, Query *query)
jstate.jumble_len = 0;
jstate.clocations_buf_size = 32;
jstate.clocations = (pgssLocationLen *)
- palloc(jstate.clocations_buf_size * sizeof(pgssLocationLen));
+ palloc0(jstate.clocations_buf_size * sizeof(pgssLocationLen));
jstate.clocations_count = 0;
jstate.highest_extern_param_id = 0;
@@ -2655,7 +2676,7 @@ JumbleRangeTable(pgssJumbleState *jstate, List *rtable)
JumbleExpr(jstate, (Node *) rte->tablefunc);
break;
case RTE_VALUES:
- JumbleExpr(jstate, (Node *) rte->values_lists);
+ JumbleExprList(jstate, (Node *) rte->values_lists);
break;
case RTE_CTE:
@@ -2699,6 +2720,203 @@ JumbleRowMarks(pgssJumbleState *jstate, List *rowMarks)
}
}
+static bool
+JumbleExprList(pgssJumbleState *jstate, Node *node)
+{
+ ListCell *temp;
+ Node *firstExpr = NULL;
+ bool merged = false;
+ bool allConst = true;
+ int currentExprIdx;
+ int lastExprLenght = 0;
+
+ if (node == NULL)
+ return merged;
+
+ Assert(IsA(node, List));
+ firstExpr = (Node *) lfirst(list_head((List *) node));
+
+ /* Guard against stack overflow due to overly complex expressions */
+ check_stack_depth();
+
+ /*
+ * We always emit the node's NodeTag, then any additional fields that are
+ * considered significant, and then we recurse to any child nodes.
+ */
+ APP_JUMB(node->type);
+
+ /*
+ * If the first expression is a constant or a list of constants, try to
+ * merge the following if they're constants as well. Otherwise do
+ * JumbleExpr as usual.
+ */
+ switch (nodeTag(firstExpr))
+ {
+ case T_List:
+ currentExprIdx = 0;
+
+ foreach(temp, (List *) node)
+ {
+ List *expr = (List *) lfirst(temp);
+ ListCell *lc;
+
+ foreach(lc, expr)
+ {
+ Node * subExpr = (Node *) lfirst(lc);
+
+ if (!IsA(subExpr, Const))
+ {
+ allConst = false;
+ break;
+ }
+ }
+
+ if (!equal(expr, firstExpr) && allConst &&
+ currentExprIdx >= pgss_merge_threshold - 1)
+ {
+ merged = true;
+
+ /*
+ * This hash is going to accumulate the following merged
+ * statements
+ */
+ if (currentExprIdx == pgss_merge_threshold - 1)
+ {
+ JumbleExpr(jstate, (Node *) expr);
+
+ /*
+ * An expr consisting of constants is already found,
+ * JumbleExpr must record it. Mark all the constants as
+ * merged, they will be the first merged but still
+ * present in the statement query.
+ */
+ Assert(jstate->clocations_count > lastExprLenght - 1);
+ for (int i = 1; i < lastExprLenght + 1; i++)
+ {
+ pgssLocationLen *loc;
+ loc = &jstate->clocations[jstate->clocations_count - i];
+ loc->merged = true;
+ }
+ currentExprIdx++;
+ }
+ else
+ foreach(lc, expr)
+ {
+ Const *c = (Const *) lfirst(lc);
+ RecordConstLocation(jstate, c->location, true);
+ }
+
+ continue;
+ }
+
+ JumbleExpr(jstate, (Node *) expr);
+ currentExprIdx++;
+ lastExprLenght = expr->length;
+ }
+ break;
+
+ case T_Const:
+ currentExprIdx = 0;
+
+ foreach(temp, (List *) node)
+ {
+ Node *expr = (Node *) lfirst(temp);
+
+ if (!equal(expr, firstExpr) && IsA(expr, Const) &&
+ currentExprIdx >= pgss_merge_threshold - 1)
+ {
+ merged = true;
+
+ /*
+ * This hash is going to accumulate the following merged
+ * statements
+ */
+ if (currentExprIdx == pgss_merge_threshold - 1)
+ {
+ JumbleExpr(jstate, expr);
+
+ /*
+ * A const expr is already found, so JumbleExpr must
+ * record it. Mark it as merged, it will be the first
+ * merged but still present in the statement query.
+ */
+ Assert(jstate->clocations_count > 0);
+ jstate->clocations[jstate->clocations_count - 1].merged = true;
+ currentExprIdx++;
+ }
+ else
+ {
+ Const *c = (Const *) expr;
+ RecordConstLocation(jstate, c->location, true);
+ }
+
+ continue;
+ }
+
+ JumbleExpr(jstate, expr);
+ currentExprIdx++;
+ }
+ break;
+
+ case T_Param:
+ currentExprIdx = 0;
+
+ foreach(temp, (List *) node)
+ {
+ Node *expr = (Node *) lfirst(temp);
+ Param *p = (Param *) expr;
+
+ if (!equal(expr, firstExpr) && IsA(expr, Param) &&
+ currentExprIdx >= pgss_merge_threshold - 1)
+ {
+
+ merged = true;
+
+ /*
+ * This hash is going to accumulate the following merged
+ * statements
+ */
+ if (currentExprIdx == pgss_merge_threshold - 1)
+ {
+ JumbleExpr(jstate, expr);
+
+ /*
+ * A const expr is already found, so JumbleExpr must
+ * record it. Mark it as merged, it will be the first
+ * merged but still present in the statement query.
+ */
+ Assert(jstate->clocations_count > 0);
+ jstate->clocations[jstate->clocations_count - 1].merged = true;
+ currentExprIdx++;
+ }
+ else
+ RecordConstLocation(jstate, p->location, true);
+
+ continue;
+ }
+
+ JumbleExpr(jstate, expr);
+
+ /*
+ * To allow merging of parameters as well in
+ * generate_normalized_query, remember it as a constant.
+ */
+ RecordConstLocation(jstate, p->location, false);
+ currentExprIdx++;
+ }
+ break;
+
+ default:
+ foreach(temp, (List *) node)
+ {
+ JumbleExpr(jstate, (Node *) lfirst(temp));
+ }
+ break;
+ }
+
+ return merged;
+}
+
/*
* Jumble an expression tree
*
@@ -2748,7 +2966,7 @@ JumbleExpr(pgssJumbleState *jstate, Node *node)
/* We jumble only the constant's type, not its value */
APP_JUMB(c->consttype);
/* Also, record its parse location for query normalization */
- RecordConstLocation(jstate, c->location);
+ RecordConstLocation(jstate, c->location, false);
}
break;
case T_Param:
@@ -2936,7 +3154,7 @@ JumbleExpr(pgssJumbleState *jstate, Node *node)
}
break;
case T_ArrayExpr:
- JumbleExpr(jstate, (Node *) ((ArrayExpr *) node)->elements);
+ JumbleExprList(jstate, (Node *) ((ArrayExpr *) node)->elements);
break;
case T_RowExpr:
JumbleExpr(jstate, (Node *) ((RowExpr *) node)->args);
@@ -3189,11 +3407,11 @@ JumbleExpr(pgssJumbleState *jstate, Node *node)
}
/*
- * Record location of constant within query string of query tree
+ * Record location of constant or a parameter within query string of query tree
* that is currently being walked.
*/
static void
-RecordConstLocation(pgssJumbleState *jstate, int location)
+RecordConstLocation(pgssJumbleState *jstate, int location, bool merged)
{
/* -1 indicates unknown or undefined location */
if (location >= 0)
@@ -3210,6 +3428,8 @@ RecordConstLocation(pgssJumbleState *jstate, int location)
jstate->clocations[jstate->clocations_count].location = location;
/* initialize lengths to -1 to simplify fill_in_constant_lengths */
jstate->clocations[jstate->clocations_count].length = -1;
+ jstate->clocations[jstate->clocations_count].merged = merged;
+
jstate->clocations_count++;
}
}
@@ -3246,6 +3466,7 @@ generate_normalized_query(pgssJumbleState *jstate, const char *query,
n_quer_loc = 0, /* Normalized query byte location */
last_off = 0, /* Offset from start for previous tok */
last_tok_len = 0; /* Length (in bytes) of that tok */
+ bool merge = false;
/*
* Get constants' lengths (core system only gives us locations). Note
@@ -3284,12 +3505,27 @@ generate_normalized_query(pgssJumbleState *jstate, const char *query,
len_to_wrt -= last_tok_len;
Assert(len_to_wrt >= 0);
- memcpy(norm_query + n_quer_loc, query + quer_loc, len_to_wrt);
- n_quer_loc += len_to_wrt;
- /* And insert a param symbol in place of the constant token */
- n_quer_loc += sprintf(norm_query + n_quer_loc, "$%d",
- i + 1 + jstate->highest_extern_param_id);
+ if (!jstate->clocations[i].merged)
+ {
+ memcpy(norm_query + n_quer_loc, query + quer_loc, len_to_wrt);
+ n_quer_loc += len_to_wrt;
+
+ /* And insert a param symbol in place of the constant token */
+ n_quer_loc += sprintf(norm_query + n_quer_loc, "$%d",
+ i + 1 + jstate->highest_extern_param_id);
+ if (merge)
+ merge = false;
+ }
+ else if (!merge)
+ {
+ memcpy(norm_query + n_quer_loc, query + quer_loc, len_to_wrt);
+ n_quer_loc += len_to_wrt;
+
+ /* Merge until a non merged constant appear */
+ merge = true;
+ n_quer_loc += sprintf(norm_query + n_quer_loc, "...");
+ }
quer_loc = off + tok_len;
last_off = off;
diff --git a/contrib/pg_stat_statements/sql/pg_stat_statements.sql b/contrib/pg_stat_statements/sql/pg_stat_statements.sql
index e9f5bb84e3..ff5c9db6c0 100644
--- a/contrib/pg_stat_statements/sql/pg_stat_statements.sql
+++ b/contrib/pg_stat_statements/sql/pg_stat_statements.sql
@@ -358,4 +358,143 @@ SELECT 42;
SELECT 42;
SELECT query, plans, calls, rows FROM pg_stat_statements ORDER BY query COLLATE "C";
+--
+-- Consts merging
+--
+SET pg_stat_statements.merge_threshold = 5;
+CREATE TABLE test_merge (id int, data int);
+
+-- IN queries
+
+-- Normal
+SELECT pg_stat_statements_reset();
+SELECT * FROM test_merge WHERE id IN (1, 2, 3);
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6);
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7);
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8);
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9);
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+-- On the merge threshold
+SELECT pg_stat_statements_reset();
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4);
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5);
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6);
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7);
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8);
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9);
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+SELECT pg_stat_statements_reset();
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5);
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6);
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7);
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8);
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9);
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+SELECT pg_stat_statements_reset();
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6);
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7);
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8);
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9);
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+-- With gaps on the threshold
+SELECT pg_stat_statements_reset();
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4);
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+SELECT pg_stat_statements_reset();
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5);
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+SELECT pg_stat_statements_reset();
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6);
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+-- test constants after merge
+SELECT pg_stat_statements_reset();
+
+SELECT * FROM test_merge WHERE id IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) and data = 2;
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+-- test prepared statement
+SELECT pg_stat_statements_reset();
+
+PREPARE query AS
+SELECT * FROM test_merge WHERE id IN ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10);
+EXECUTE query (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+-- VALUES queries
+
+-- Normal
+SELECT pg_stat_statements_reset();
+SELECT * FROM (VALUES (1), (2), (3)) q;
+SELECT * FROM (VALUES (1), (2), (3), (4)) q;
+SELECT * FROM (VALUES (1), (2), (3), (4), (5)) q;
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6)) q;
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7)) q;
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7), (8)) q;
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7), (8), (9)) q;
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+SELECT pg_stat_statements_reset();
+SELECT * FROM (VALUES (1, 1), (2, 2), (3, 3)) q;
+SELECT * FROM (VALUES (1, 1), (2, 2), (3, 3), (4, 4)) q;
+SELECT * FROM (VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5)) q;
+SELECT * FROM (VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)) q;
+SELECT * FROM (VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6), (7, 7)) q;
+SELECT * FROM (VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6), (7, 7), (8, 8)) q;
+SELECT * FROM (VALUES (1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6), (7, 7), (8, 8), (9, 9)) q;
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+-- On the merge threshold
+SELECT pg_stat_statements_reset();
+SELECT * FROM (VALUES (1), (2), (3), (4)) q;
+SELECT * FROM (VALUES (1), (2), (3), (4), (5)) q;
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6)) q;
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7)) q;
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7), (8)) q;
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7), (8), (9)) q;
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+-- With gaps on the treshold
+SELECT pg_stat_statements_reset();
+SELECT * FROM (VALUES (1), (2), (3), (4)) q;
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7), (8), (9)) q;
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+SELECT pg_stat_statements_reset();
+SELECT * FROM (VALUES (1), (2), (3), (4), (5)) q;
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7), (8), (9)) q;
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
+SELECT pg_stat_statements_reset();
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6)) q;
+SELECT * FROM (VALUES (1), (2), (3), (4), (5), (6), (7), (8), (9)) q;
+SELECT query, calls FROM pg_stat_statements ORDER BY query COLLATE "C";
+
DROP EXTENSION pg_stat_statements;
--
2.21.0
