文章目录
环境
系统平台：Linux x86-64 Red Hat Enterprise Linux 7,银河麒麟 （X86_64）
版本：9.0,9.0.3,9.0.4
文档用途
版本说明
- 本文涉及的SQL脚本适用于pg_stat_statements 1.9以后，即HGDB v9以后的版本，查看插件版本可使用psql登陆后执行\dx查看。
- 本文不涉及插件pg_stat_statements的部署说明。
详细信息
使用说明
- 插件安装完毕以后，pg_stat_statements表中没有时间戳列，因此采集的数据起始时间为安装插件的时间，采集的数据为安装插件起的累计数据。
- 如果有定向采集的需求，建议在执行查询pg_stat_statements前手动重置pg_stat_statements的记录，并等待采集一段时间后执行查询命令。
重置pg_stat_statements记录
sql
SELECT pg_stat_statements_reset();查询执行时间的TOP SQL
sql
SELECT
substring(query,1,50),
queryid,
calls,
total_exec_time,
ROUND(CAST(100.0 * total_exec_time / NULLIF(SUM(total_exec_time) OVER (), 0) AS numeric), 2) AS percentage_total_time,
ROUND(CAST(total_exec_time / NULLIF(calls, 0) AS numeric), 2) AS avg_time_per_call
FROM pg_stat_statements
ORDER BY total_exec_time DESC
LIMIT 20;
substring | queryid | calls | total_exec_time | percentage_total_time | avg_time_per_call
----------------------------------------------------+----------------------+-------+--------------------+-----------------------+-------------------
SELECT take_sample() | -1885067886343922859 | 1 | 957.25066 | 33.30 | 957.25
SELECT * FROM take_sample_subset(1,0) | 4279534554688483984 | 1 | 957.1010279999999 | 33.30 | 957.10
UPDATE last_stat_tables ulst +| 980343821264315606 | 1 | 706.703659 | 24.59 | 706.70
SET in_sample = $ | | | | |
INSERT INTO last_stat_indexes( +| -7952618813933756158 | 2 | 32.812992 | 1.14 | 16.41
server_id, +| | | | |
| | | | |
INSERT INTO last_stat_tables( +| -4538647355087417803 | 2 | 27.614337 | 0.96 | 13.81
server_id, +| | | | |
| | | | |
SELECT collect_pg_stat_statements_stats(server_pro | 4567360260458699963 | 1 | 27.481461 | 0.96 | 27.48
SELECT num_nulls(min(s.sample_id),max(s.sample_id) | 7475033235738850795 | 1 | 17.213193 | 0.60 | 17.21
DELETE FROM samples dsmp +| -154048289740345458 | 1 | 15.040277 | 0.52 | 15.04
USING +| | | | |
servers srv +| | | | |
| | | | |
SELECT st.relid,st.schemaname,st.relname,st.seq_sc | -3629045378463163003 | 1 | 12.123222 | 0.42 | 12.12
UPDATE last_stat_tables ulst +| -5907021954271659257 | 1 | 9.78708 | 0.34 | 9.79
SET in_sample = $ | | | | |
UPDATE last_stat_indexes uli +| 14458817000285957 | 1 | 8.935439 | 0.31 | 8.94
SET in_sample = $ | | | | |
UPDATE last_stat_tables ulst +| 603590958747687395 | 1 | 6.345096 | 0.22 | 6.35
SET in_sample = $ | | | | |
SELECT save_pg_stat_statements(sserver_id, s_id, +| -2680229593466005629 | 1 | 6.225859 | 0.22 | 6.23
| | | | |
INSERT INTO sample_stat_tables ( +| 3522316392995680077 | 1 | 6.038669 | 0.21 | 6.04
server_id, +| | | | |
| | | | |
UPDATE last_stat_indexes cur +| -3677961896277714985 | 1 | 5.474875 | 0.19 | 5.47
SET relsize = lst | | | | |
INSERT INTO sample_stat_tables_total( +| 3227103508814905323 | 1 | 4.941876000000001 | 0.17 | 4.94
server | | | | |
ANALYZE last_stat_tables_srv1 | 4355419411286857634 | 1 | 4.582182 | 0.16 | 4.58
SELECT dblink_connect($9,db_connstr) | 7643119528241000382 | 2 | 4.570225000000001 | 0.16 | 2.29
UPDATE last_stat_tables cur +| 322557813175172263 | 1 | 4.3211129999999995 | 0.15 | 4.32
SET relsize = lst. | | | | |
SELECT $4 FROM ONLY "public"."sample_stat_database | 4289266549190127233 | 2945 | 4.097789999999995 | 0.14 | 0.00
(20 rows)- calls：sql被调用次数。
- total_exec_time：sql总执行时间ms=calls*avg_time_per_call。
- percentage_total_time：总执行时间的占比%。
- avg_time_per_call：sql平均执行时间，单位ms。
查询占用CPU使用率的TOP SQL
sql
select queryid,userid::regrole 用户名, (select datname from pg_database where oid=dbid)数据库,calls as 总调用次数,round((100 * total_exec_time / sum(total_exec_time::numeric) over ())::numeric, 2) as cpu使用率,substring(query,1,50) 查询语句 from pg_stat_statements order by total_exec_time desc limit 20;
queryid | 用户名 | 数据库 | 总调用次数 | cpu使用率 | 查询语句
----------------------+--------+--------+------------+-----------+----------------------------------------------------
-1885067886343922859 | highgo | tpcc | 1 | 33.29 | SELECT take_sample()
4279534554688483984 | highgo | tpcc | 1 | 33.29 | SELECT * FROM take_sample_subset(1,0)
980343821264315606 | highgo | tpcc | 1 | 24.58 | UPDATE last_stat_tables ulst +
| | | | | SET in_sample = $
-7952618813933756158 | highgo | tpcc | 2 | 1.14 | INSERT INTO last_stat_indexes( +
| | | | | server_id, +
| | | | |
-4538647355087417803 | highgo | tpcc | 2 | 0.96 | INSERT INTO last_stat_tables( +
| | | | | server_id, +
| | | | |
4567360260458699963 | highgo | tpcc | 1 | 0.96 | SELECT collect_pg_stat_statements_stats(server_pro
7475033235738850795 | highgo | tpcc | 1 | 0.60 | SELECT num_nulls(min(s.sample_id),max(s.sample_id)
-154048289740345458 | highgo | tpcc | 1 | 0.52 | DELETE FROM samples dsmp +
| | | | | USING +
| | | | | servers srv +
| | | | |
-3629045378463163003 | highgo | highgo | 1 | 0.42 | SELECT st.relid,st.schemaname,st.relname,st.seq_sc
-5907021954271659257 | highgo | tpcc | 1 | 0.34 | UPDATE last_stat_tables ulst +
| | | | | SET in_sample = $
14458817000285957 | highgo | tpcc | 1 | 0.31 | UPDATE last_stat_indexes uli +
| | | | | SET in_sample = $
603590958747687395 | highgo | tpcc | 1 | 0.22 | UPDATE last_stat_tables ulst +
| | | | | SET in_sample = $
-2680229593466005629 | highgo | tpcc | 1 | 0.22 | SELECT save_pg_stat_statements(sserver_id, s_id, +
| | | | |
3522316392995680077 | highgo | tpcc | 1 | 0.21 | INSERT INTO sample_stat_tables ( +
| | | | | server_id, +
| | | | |
-3677961896277714985 | highgo | tpcc | 1 | 0.19 | UPDATE last_stat_indexes cur +
| | | | | SET relsize = lst
3227103508814905323 | highgo | tpcc | 1 | 0.17 | INSERT INTO sample_stat_tables_total( +
| | | | | server
4355419411286857634 | highgo | tpcc | 1 | 0.16 | ANALYZE last_stat_tables_srv1
7643119528241000382 | highgo | tpcc | 2 | 0.16 | SELECT dblink_connect($9,db_connstr)
322557813175172263 | highgo | tpcc | 1 | 0.15 | UPDATE last_stat_tables cur +
| | | | | SET relsize = lst.
4289266549190127233 | highgo | tpcc | 2945 | 0.14 | SELECT $4 FROM ONLY "public"."sample_stat_database
(20 rows)- CPU使用率：为该SQL总调用次数的CPU使用率，平均单条SQL CPU使用率=CPU使用率/总调用次数。