PostgreSQLDBA(96)-SystemConf(client_min_messages)
PostgreSQL提供了参数client_min_messages用以控制返回给客户的消息级别，不同的级别返回的消息大小不同，默认为NOTICE。在通常情况下，如果客户端执行的SQL语句不频繁的话，使用默认参数即可，但如果客户端执行大量的SQL，设置该参数为较高级别就显得有意义了：可以减少消息的大小从而降低网络负载，提升吞吐。
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参数简介
下面创建一个存储过程，raise notice显示通知信息
[local]:5432 pg12@testdb=# CREATE OR REPLACE FUNCTION foo() RETURNS void AS
pg12@testdb-# $$
pg12@testdb$# BEGIN
pg12@testdb$# RAISE NOTICE 'some message';
pg12@testdb$# RETURN;
pg12@testdb$# END;
pg12@testdb$# $$ LANGUAGE 'plpgsql';
CREATE FUNCTION
Time: 389.227 ms
[local]:5432 pg12@testdb=#
执行存储过程
[local]:5432 pg12@testdb=# show client_min_messages;
client_min_messages
---------------------
notice
(1 row)
Time: 0.589 ms
[local]:5432 pg12@testdb=# select foo();
NOTICE: some message
foo
-----
(1 row)
Time: 26.838 ms
[local]:5432 pg12@testdb=# set client_min_messages='ERROR';
SET
Time: 0.361 ms
[local]:5432 pg12@testdb=# select foo();
foo
-----
(1 row)
Time: 1.638 ms
[local]:5432 pg12@testdb=#
在client_min_messages设置为ERROR后，不再显示NOTICE通知信息。
下面使用benchmarksql压测工具测试该参数从NOTICE修改为ERROR后的性能变化。
1.NOTICE
[xdb@localhost run]$ ./runBenchmark.sh props.pg
2019-09-25 12:15:25,434 INFO - Term-00,
2019-09-25 12:15:25,435 INFO - Term-00, +-------------------------------------------------------------+
2019-09-25 12:15:25,435 INFO - Term-00, BenchmarkSQL v4.1.1
2019-09-25 12:15:25,435 INFO - Term-00, +-------------------------------------------------------------+
2019-09-25 12:15:25,435 INFO - Term-00, (c) 2003, Raul Barbosa
2019-09-25 12:15:25,435 INFO - Term-00, (c) 2004-2016, Denis Lussier
2019-09-25 12:15:25,435 INFO - Term-00, (c) 2016, Jan Wieck
2019-09-25 12:15:25,435 INFO - Term-00, +-------------------------------------------------------------+
2019-09-25 12:15:25,435 INFO - Term-00,
2019-09-25 12:15:25,435 INFO - Term-00, driver=org.postgresql.Driver
2019-09-25 12:15:25,435 INFO - Term-00, conn=jdbc:postgresql://192.168.26.28:5432/benchmarkdb
2019-09-25 12:15:25,435 INFO - Term-00, user=pg12
2019-09-25 12:15:25,435 INFO - Term-00,
2019-09-25 12:15:25,435 INFO - Term-00, warehouses=32
2019-09-25 12:15:25,435 INFO - Term-00, terminals=20
2019-09-25 12:15:25,435 INFO - Term-00, runMins=5
2019-09-25 12:15:25,435 INFO - Term-00, limitTxnsPerMin=0
2019-09-25 12:15:25,435 INFO - Term-00,
2019-09-25 12:15:25,435 INFO - Term-00, newOrderWeight=45
2019-09-25 12:15:25,435 INFO - Term-00, paymentWeight=43
2019-09-25 12:15:25,435 INFO - Term-00, orderStatusWeight=4 Term-00, Running Average
2019-09-25 12:20:25,706 INFO - Term-00, 52216 Memory Usage: 26MB / 37MB
2019-09-25 12:20:25,706 INFO - Term-00,
2019-09-25 12:20:25,707 INFO - Term-00, Measured tpmC (NewOrders) = 7448.89
2019-09-25 12:20:25,707 INFO - Term-00, Measured tpmTOTAL = 16626.58
2019-09-25 12:20:25,707 INFO - Term-00, Session Start = 2019-09-25 12:15:25
2019-09-25 12:20:25,707 INFO - Term-00, Session End = 2019-09-25 12:20:25
2019-09-25 12:20:25,707 INFO - Term-00, Transaction Count = 83171
[xdb@localhost run]$
[xdb@localhost run]$
2.ERROR
[xdb@localhost run]$ ./runBenchmark.sh props.pg
2019-09-25 12:22:57,954 INFO - Term-00,
2019-09-25 12:22:57,954 INFO - Term-00, +-------------------------------------------------------------+
2019-09-25 12:22:57,954 INFO - Term-00, BenchmarkSQL v4.1.1
2019-09-25 12:22:57,954 INFO - Term-00, +-------------------------------------------------------------+
2019-09-25 12:22:57,954 INFO - Term-00, (c) 2003, Raul Barbosa
2019-09-25 12:22:57,955 INFO - Term-00, (c) 2004-2016, Denis Lussier
2019-09-25 12:22:57,955 INFO - Term-00, (c) 2016, Jan Wieck
2019-09-25 12:22:57,955 INFO - Term-00, +-------------------------------------------------------------+
2019-09-25 12:22:57,955 INFO - Term-00,
2019-09-25 12:22:57,955 INFO - Term-00, driver=org.postgresql.Driver
2019-09-25 12:22:57,955 INFO - Term-00, conn=jdbc:postgresql://192.168.26.28:5432/benchmarkdb
2019-09-25 12:22:57,955 INFO - Term-00, user=pg12
2019-09-25 12:22:57,955 INFO - Term-00,
2019-09-25 12:22:57,955 INFO - Term-00, warehouses=32
2019-09-25 12:22:57,955 INFO - Term-00, terminals=20
2019-09-25 12:22:57,955 INFO - Term-00, runMins=5
2019-09-25 12:22:57,955 INFO - Term-00, limitTxnsPerMin=0
2019-09-25 12:22:57,955 INFO - Term-00,
2019-09-25 12:22:57,955 INFO - Term-00, newOrderWeight=45
2019-09-25 12:22:57,955 INFO - Term-00, paymentWeight=43
2019-09-25 12:22:57,955 INFO - Term-00, orderStatusWeight=4 Term-00, Running Average
2019-09-25 12:27:58,267 INFO - Term-00, 79156 Memory Usage: 18MB / 37MB
2019-09-25 12:27:58,267 INFO - Term-00,
2019-09-25 12:27:58,267 INFO - Term-00, Measured tpmC (NewOrders) = 7815.72
2019-09-25 12:27:58,267 INFO - Term-00, Measured tpmTOTAL = 17440.12
2019-09-25 12:27:58,267 INFO - Term-00, Session Start = 2019-09-25 12:22:58
2019-09-25 12:27:58,267 INFO - Term-00, Session End = 2019-09-25 12:27:58
2019-09-25 12:27:58,268 INFO - Term-00, Transaction Count = 87254
[xdb@localhost run]$
TPMC 7815 vs 7448，提升比例为4.9%
为免系统随机扰动导致的误差，重新测试了一遍
-- NONE
2019-09-25 14:53:05,384 INFO - Term-00, Measured tpmC (NewOrders) = 7168.43
2019-09-25 14:53:05,384 INFO - Term-00, Measured tpmTOTAL = 15890.5
2019-09-25 14:53:05,384 INFO - Term-00, Session Start = 2019-09-25 14:48:05
2019-09-25 14:53:05,385 INFO - Term-00, Session End = 2019-09-25 14:53:05
2019-09-25 14:53:05,385 INFO - Term-00, Transaction Count = 79491
[xdb@localhost run]$
-- vacuum full;
-- client_min_messages=error
2019-09-25 14:44:29,101 INFO - Term-00, Measured tpmC (NewOrders) = 7239.02
2019-09-25 14:44:29,101 INFO - Term-00, Measured tpmTOTAL = 16079.06
2019-09-25 14:44:29,101 INFO - Term-00, Session Start = 2019-09-25 14:39:28
2019-09-25 14:44:29,102 INFO - Term-00, Session End = 2019-09-25 14:44:29
2019-09-25 14:44:29,102 INFO - Term-00, Transaction Count = 80434
-- vacuum full;
-- update_process_title=off
-- track_activities=off
2019-09-25 15:01:11,861 INFO - Term-00, Measured tpmC (NewOrders) = 7253.43
2019-09-25 15:01:11,861 INFO - Term-00, Measured tpmTOTAL = 16111.73
2019-09-25 15:01:11,862 INFO - Term-00, Session Start = 2019-09-25 14:56:11
2019-09-25 15:01:11,862 INFO - Term-00, Session End = 2019-09-25 15:01:11
2019-09-25 15:01:11,862 INFO - Term-00, Transaction Count = 80584
-- vacuum full;
-- client_min_messages=error
-- update_process_title=off
-- track_activities=off
2019-09-25 15:08:46,923 INFO - Term-00, Measured tpmC (NewOrders) = 7194.55
2019-09-25 15:08:46,923 INFO - Term-00, Measured tpmTOTAL = 16059.38
2019-09-25 15:08:46,923 INFO - Term-00, Session Start = 2019-09-25 15:03:46
2019-09-25 15:08:46,923 INFO - Term-00, Session End = 2019-09-25 15:08:46
2019-09-25 15:08:46,923 INFO - Term-00, Transaction Count = 80350
似乎没有什么效果。
参考资料
Reducing log messages on the client
标题名称：PostgreSQLDBA(96)-SystemConf(client_min_messages)
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