1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
|
--
-- Statement level tracking
--
SET pg_stat_statements.track_utility = TRUE;
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
t
---
t
(1 row)
-- DO block - top-level tracking.
CREATE TABLE stats_track_tab (x int);
SET pg_stat_statements.track = 'top';
DELETE FROM stats_track_tab;
DO $$
BEGIN
DELETE FROM stats_track_tab;
END;
$$ LANGUAGE plpgsql;
SELECT toplevel, calls, query FROM pg_stat_statements
WHERE query LIKE '%DELETE%' ORDER BY query COLLATE "C", toplevel;
toplevel | calls | query
----------+-------+--------------------------------
t | 1 | DELETE FROM stats_track_tab
t | 1 | DO $$ +
| | BEGIN +
| | DELETE FROM stats_track_tab;+
| | END; +
| | $$ LANGUAGE plpgsql
(2 rows)
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
t
---
t
(1 row)
-- DO block - all-level tracking.
SET pg_stat_statements.track = 'all';
DELETE FROM stats_track_tab;
DO $$
BEGIN
DELETE FROM stats_track_tab;
END; $$;
DO LANGUAGE plpgsql $$
BEGIN
-- this is a SELECT
PERFORM 'hello world'::TEXT;
END; $$;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C", toplevel;
toplevel | calls | query
----------+-------+----------------------------------------------------
f | 1 | DELETE FROM stats_track_tab
t | 1 | DELETE FROM stats_track_tab
t | 1 | DO $$ +
| | BEGIN +
| | DELETE FROM stats_track_tab; +
| | END; $$
t | 1 | DO LANGUAGE plpgsql $$ +
| | BEGIN +
| | -- this is a SELECT +
| | PERFORM 'hello world'::TEXT; +
| | END; $$
f | 1 | SELECT $1::TEXT
t | 1 | SELECT pg_stat_statements_reset() IS NOT NULL AS t
t | 1 | SET pg_stat_statements.track = 'all'
(7 rows)
-- Procedure with multiple utility statements.
CREATE OR REPLACE PROCEDURE proc_with_utility_stmt()
LANGUAGE SQL
AS $$
SHOW pg_stat_statements.track;
show pg_stat_statements.track;
SHOW pg_stat_statements.track_utility;
$$;
SET pg_stat_statements.track_utility = TRUE;
-- all-level tracking.
SET pg_stat_statements.track = 'all';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
t
---
t
(1 row)
CALL proc_with_utility_stmt();
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C", toplevel;
toplevel | calls | query
----------+-------+----------------------------------------------------
t | 1 | CALL proc_with_utility_stmt()
t | 1 | SELECT pg_stat_statements_reset() IS NOT NULL AS t
f | 2 | SHOW pg_stat_statements.track
f | 1 | SHOW pg_stat_statements.track_utility
(4 rows)
-- top-level tracking.
SET pg_stat_statements.track = 'top';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
t
---
t
(1 row)
CALL proc_with_utility_stmt();
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C", toplevel;
toplevel | calls | query
----------+-------+----------------------------------------------------
t | 1 | CALL proc_with_utility_stmt()
t | 1 | SELECT pg_stat_statements_reset() IS NOT NULL AS t
(2 rows)
-- DO block - top-level tracking without utility.
SET pg_stat_statements.track = 'top';
SET pg_stat_statements.track_utility = FALSE;
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
t
---
t
(1 row)
DELETE FROM stats_track_tab;
DO $$
BEGIN
DELETE FROM stats_track_tab;
END; $$;
DO LANGUAGE plpgsql $$
BEGIN
-- this is a SELECT
PERFORM 'hello world'::TEXT;
END; $$;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C", toplevel;
toplevel | calls | query
----------+-------+----------------------------------------------------
t | 1 | DELETE FROM stats_track_tab
t | 1 | SELECT pg_stat_statements_reset() IS NOT NULL AS t
(2 rows)
-- DO block - all-level tracking without utility.
SET pg_stat_statements.track = 'all';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
t
---
t
(1 row)
DELETE FROM stats_track_tab;
DO $$
BEGIN
DELETE FROM stats_track_tab;
END; $$;
DO LANGUAGE plpgsql $$
BEGIN
-- this is a SELECT
PERFORM 'hello world'::TEXT;
END; $$;
SELECT toplevel, calls, query FROM pg_stat_statements
ORDER BY query COLLATE "C", toplevel;
toplevel | calls | query
----------+-------+----------------------------------------------------
f | 1 | DELETE FROM stats_track_tab
t | 1 | DELETE FROM stats_track_tab
f | 1 | SELECT $1::TEXT
t | 1 | SELECT pg_stat_statements_reset() IS NOT NULL AS t
(4 rows)
-- PL/pgSQL function - top-level tracking.
SET pg_stat_statements.track = 'top';
SET pg_stat_statements.track_utility = FALSE;
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
t
---
t
(1 row)
CREATE FUNCTION PLUS_TWO(i INTEGER) RETURNS INTEGER AS $$
DECLARE
r INTEGER;
BEGIN
SELECT (i + 1 + 1.0)::INTEGER INTO r;
RETURN r;
END; $$ LANGUAGE plpgsql;
SELECT PLUS_TWO(3);
plus_two
----------
5
(1 row)
SELECT PLUS_TWO(7);
plus_two
----------
9
(1 row)
-- SQL function --- use LIMIT to keep it from being inlined
CREATE FUNCTION PLUS_ONE(i INTEGER) RETURNS INTEGER AS
$$ SELECT (i + 1.0)::INTEGER LIMIT 1 $$ LANGUAGE SQL;
SELECT PLUS_ONE(8);
plus_one
----------
9
(1 row)
SELECT PLUS_ONE(10);
plus_one
----------
11
(1 row)
SELECT calls, rows, query FROM pg_stat_statements ORDER BY query COLLATE "C";
calls | rows | query
-------+------+----------------------------------------------------
2 | 2 | SELECT PLUS_ONE($1)
2 | 2 | SELECT PLUS_TWO($1)
1 | 1 | SELECT pg_stat_statements_reset() IS NOT NULL AS t
(3 rows)
-- immutable SQL function --- can be executed at plan time
CREATE FUNCTION PLUS_THREE(i INTEGER) RETURNS INTEGER AS
$$ SELECT i + 3 LIMIT 1 $$ IMMUTABLE LANGUAGE SQL;
SELECT PLUS_THREE(8);
plus_three
------------
11
(1 row)
SELECT PLUS_THREE(10);
plus_three
------------
13
(1 row)
SELECT toplevel, calls, rows, query FROM pg_stat_statements ORDER BY query COLLATE "C";
toplevel | calls | rows | query
----------+-------+------+------------------------------------------------------------------------------
t | 2 | 2 | SELECT PLUS_ONE($1)
t | 2 | 2 | SELECT PLUS_THREE($1)
t | 2 | 2 | SELECT PLUS_TWO($1)
t | 1 | 3 | SELECT calls, rows, query FROM pg_stat_statements ORDER BY query COLLATE "C"
t | 1 | 1 | SELECT pg_stat_statements_reset() IS NOT NULL AS t
(5 rows)
-- PL/pgSQL function - all-level tracking.
SET pg_stat_statements.track = 'all';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
t
---
t
(1 row)
-- we drop and recreate the functions to avoid any caching funnies
DROP FUNCTION PLUS_ONE(INTEGER);
DROP FUNCTION PLUS_TWO(INTEGER);
DROP FUNCTION PLUS_THREE(INTEGER);
-- PL/pgSQL function
CREATE FUNCTION PLUS_TWO(i INTEGER) RETURNS INTEGER AS $$
DECLARE
r INTEGER;
BEGIN
SELECT (i + 1 + 1.0)::INTEGER INTO r;
RETURN r;
END; $$ LANGUAGE plpgsql;
SELECT PLUS_TWO(-1);
plus_two
----------
1
(1 row)
SELECT PLUS_TWO(2);
plus_two
----------
4
(1 row)
-- SQL function --- use LIMIT to keep it from being inlined
CREATE FUNCTION PLUS_ONE(i INTEGER) RETURNS INTEGER AS
$$ SELECT (i + 1.0)::INTEGER LIMIT 1 $$ LANGUAGE SQL;
SELECT PLUS_ONE(3);
plus_one
----------
4
(1 row)
SELECT PLUS_ONE(1);
plus_one
----------
2
(1 row)
SELECT calls, rows, query FROM pg_stat_statements ORDER BY query COLLATE "C";
calls | rows | query
-------+------+----------------------------------------------------
2 | 2 | SELECT (i + $2 + $3)::INTEGER
2 | 2 | SELECT (i + $2)::INTEGER LIMIT $3
2 | 2 | SELECT PLUS_ONE($1)
2 | 2 | SELECT PLUS_TWO($1)
1 | 1 | SELECT pg_stat_statements_reset() IS NOT NULL AS t
(5 rows)
-- immutable SQL function --- can be executed at plan time
CREATE FUNCTION PLUS_THREE(i INTEGER) RETURNS INTEGER AS
$$ SELECT i + 3 LIMIT 1 $$ IMMUTABLE LANGUAGE SQL;
SELECT PLUS_THREE(8);
plus_three
------------
11
(1 row)
SELECT PLUS_THREE(10);
plus_three
------------
13
(1 row)
SELECT toplevel, calls, rows, query FROM pg_stat_statements ORDER BY query COLLATE "C";
toplevel | calls | rows | query
----------+-------+------+------------------------------------------------------------------------------
f | 2 | 2 | SELECT (i + $2 + $3)::INTEGER
f | 2 | 2 | SELECT (i + $2)::INTEGER LIMIT $3
t | 2 | 2 | SELECT PLUS_ONE($1)
t | 2 | 2 | SELECT PLUS_THREE($1)
t | 2 | 2 | SELECT PLUS_TWO($1)
t | 1 | 5 | SELECT calls, rows, query FROM pg_stat_statements ORDER BY query COLLATE "C"
f | 2 | 2 | SELECT i + $2 LIMIT $3
t | 1 | 1 | SELECT pg_stat_statements_reset() IS NOT NULL AS t
(8 rows)
--
-- pg_stat_statements.track = none
--
SET pg_stat_statements.track = 'none';
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
t
---
t
(1 row)
SELECT 1 AS "one";
one
-----
1
(1 row)
SELECT 1 + 1 AS "two";
two
-----
2
(1 row)
SELECT calls, rows, query FROM pg_stat_statements ORDER BY query COLLATE "C";
calls | rows | query
-------+------+-------
(0 rows)
SELECT pg_stat_statements_reset() IS NOT NULL AS t;
t
---
t
(1 row)
|
