本篇内容主要讲解“分析PostgreSQL日志相关的配置参数log_XXX”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“分析PostgreSQL日志相关的配置参数log_XXX”吧!
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概览
在新initdb的数据库上查询pg_settings，可查询PostgreSQL中与log的参数包括：
[test@localhost ~]$ psql
Expanded display is used automatically.
psql (12.1)
Type "help" for help.
[local:/var/run/test]:5000 test@testdb=# select category,name,setting from pg_settings where name like 'log%' order by category;
category | name | setting
--------------------------------------+-----------------------------+--------------------------------
Reporting and Logging / What to Log | log_lock_waits | off
Reporting and Logging / What to Log | log_checkpoints | off
Reporting and Logging / What to Log | log_connections | off
Reporting and Logging / What to Log | log_timezone | PRC
Reporting and Logging / What to Log | log_temp_files | -1
Reporting and Logging / What to Log | log_disconnections | off
Reporting and Logging / What to Log | log_duration | off
Reporting and Logging / What to Log | log_error_verbosity | default
Reporting and Logging / What to Log | log_statement | none
Reporting and Logging / What to Log | log_replication_commands | off
Reporting and Logging / What to Log | log_autovacuum_min_duration | -1
Reporting and Logging / What to Log | log_hostname | off
Reporting and Logging / What to Log | log_line_prefix | %m [%p]
Reporting and Logging / When to Log | log_min_duration_statement | -1
Reporting and Logging / When to Log | log_min_error_statement | error
Reporting and Logging / When to Log | log_min_messages | warning
Reporting and Logging / When to Log | log_transaction_sample_rate | 0
Reporting and Logging / Where to Log | log_destination | stderr
Reporting and Logging / Where to Log | log_filename | postgresql-%Y-%m-%d_%H%M%S.log
Reporting and Logging / Where to Log | logging_collector | off
Reporting and Logging / Where to Log | log_truncate_on_rotation | off
Reporting and Logging / Where to Log | log_rotation_size | 10240
Reporting and Logging / Where to Log | log_file_mode | 0600
Reporting and Logging / Where to Log | log_rotation_age | 1440
Reporting and Logging / Where to Log | log_directory | log
Statistics / Monitoring | log_statement_stats | off
Statistics / Monitoring | log_planner_stats | off
Statistics / Monitoring | log_executor_stats | off
Statistics / Monitoring | log_parser_stats | off
(29 rows)
[local:/var/run/test]:5000 test@testdb=#
log_打头的参数有29个，下面从where、when、what这几个维度来解析这些参数，本节是第三部分，介绍what to log。
What to log
debug_print_parse
是否打印分析阶段的查询树，默认为off-不打印
debug_print_rewritten
是否打印查询重写阶段的查询树，默认为off-不打印
debug_print_plan
是否打印计划阶段的计划树，默认为off-不打印
debug_pretty_print
是否以优雅的方式打印？默认为on
log_checkpoints
是否记录checkpoint信息，默认为off。
在checkpoint发生时，PG会记录相关的信息
checkpoint_timeout = 1min # range 30s-1d
checkpoint_completion_target = 0.5 # checkpoint target duration, 0.0 - 1.0
#checkpoint_flush_after = 256kB # measured in pages, 0 disables
#checkpoint_warning = 30s # 0 disables
log_checkpoints = on
插入数据，在检查点发生时，可以看到检查点的相关信息输出
2019-12-30 14:27:03.618 CST [2224] LOG: duration: 106.374 ms statement: insert into tbl select x,'c1'||x from generate_series(1,10000) x;
2019-12-30 14:28:00.428 CST [2166] LOG: checkpoint starting: time
2019-12-30 14:28:06.387 CST [2166] LOG: checkpoint complete: wrote 59 buffers (0.4%); 0 WAL file(s) added, 0 removed, 0 recycled; write=5.949 s, sync=0.001 s, total=5.958 s; sync files=3, longest=0.001 s, average=0.000 s; distance=764 kB, estimate=764 kB
log_connections
记录登录信息，包括什么时候有连接请求，哪个用户连接的是哪个数据库；如连接失败，也会记录相关信息。
###修改配置信息
[test@localhost ~]$ grep 'log_connections' $PGDATA/postgresql.conf
# "postgres -c log_connections=on". Some parameters can be changed at run time
log_connections = on
[test@localhost ~]$ pg_ctl reload
server signaled
[test@localhost ~]$
###日志输出
2019-12-30 14:33:02.527 CST [2634] LOG: connection received: host=[local]
2019-12-30 14:33:02.531 CST [2634] LOG: connection authorized: user=test database=testdb application_name=psql
log_disconnections
记录连接断开登录信息
###
[test@localhost ~]$ grep 'log_disconnections' $PGDATA/postgresql.conf
log_disconnections = on
[test@localhost ~]$
###日志输出
2019-12-30 14:34:57.646 CST [2734] LOG: disconnection: session time: 0:00:04.885 user=test database=testdb host=[local]
log_duration
记录执行时间，仅记录执行时间，没有其他多余的信息。默认为on。
2019-12-30 14:36:49.149 CST [2224] LOG: duration: 12.178 ms
log_error_verbosity
出现错误时的日志诊断信息级别，可选项包括：terse, default, or verbose，默认值为default
使用verbose，可以看到哪个源文件的哪一行，方便诊断
###创建测试对象
[local:/data/run/test]:5000 test@testdb=# create view vw_tbl as select * from tbl;
CREATE VIEW
[local:/data/run/test]:5000 test@testdb=#
###terse
2019-12-30 14:41:30.395 CST [2163] LOG: parameter "log_error_verbosity" changed to "terse"
2019-12-30 14:41:39.689 CST [2224] ERROR: cannot drop table tbl because other objects depend on it
###default
2019-12-30 14:42:27.106 CST [2163] LOG: parameter "log_error_verbosity" changed to "default"
2019-12-30 14:42:33.287 CST [2224] ERROR: cannot drop table tbl because other objects depend on it
2019-12-30 14:42:33.287 CST [2224] DETAIL: view vw_tbl depends on table tbl
2019-12-30 14:42:33.287 CST [2224] HINT: Use DROP ... CASCADE to drop the dependent objects too.
###verbose
2019-12-30 14:43:29.654 CST [2163] LOG: 00000: parameter "log_error_verbosity" changed to "verbose"
2019-12-30 14:43:29.654 CST [2163] LOCATION: ProcessConfigFileInternal, guc-file.l:456
2019-12-30 14:43:32.790 CST [2224] ERROR: 2BP01: cannot drop table tbl because other objects depend on it
2019-12-30 14:43:32.790 CST [2224] DETAIL: view vw_tbl depends on table tbl
2019-12-30 14:43:32.790 CST [2224] HINT: Use DROP ... CASCADE to drop the dependent objects too.
2019-12-30 14:43:32.790 CST [2224] LOCATION: reportDependentObjects, dependency.c:1196
log_hostname
是否记录主机名称，默认为off。
log_line_prefix
每一行日志前的前缀。默认为’%m [%p] ‘，可使用的通配符包括：
%a – application name
%u – user name
%d – database name
%r – remote host and port
%h – remote host
%p – process ID
%t – timestamp without milliseconds
%m – timestamp with milliseconds
%i – command tag
%e – SQL state
%c – session ID
%l – session line number
%s – session start timestamp
%v – virtual transaction ID
%x – transaction ID (0 if none)
%q – stop here in non-session processes
%% – ‘%’
把该参数修改为’%m %u@%d %p %r’，reload后的日志输出：
2019-12-30 15:20:31.707 CST @ [2163] LOG: 00000: parameter "log_line_prefix" changed to "%m %u@%d [%p] %r "
2019-12-30 15:20:31.707 CST @ [2163] LOCATION: ProcessConfigFileInternal, guc-file.l:456
2019-12-30 15:20:40.148 CST test@testdb [2224] [local] ERROR: 2BP01: cannot drop table tbl because other objects depend on it
2019-12-30 15:20:40.148 CST test@testdb [2224] [local] DETAIL: view vw_tbl depends on table tbl
2019-12-30 15:20:40.148 CST test@testdb [2224] [local] HINT: Use DROP ... CASCADE to drop the dependent objects too.
2019-12-30 15:20:40.148 CST test@testdb [2224] [local] LOCATION: reportDependentObjects, dependency.c:1196
log_lock_waits
记录等待时间超过deadlock_timeout（默认为1s）的lock。
2019-12-30 15:27:06.637 CST @ [2163] LOG: 00000: parameter "log_lock_waits" changed to "on"
2019-12-30 15:27:06.637 CST @ [2163] LOCATION: ProcessConfigFileInternal, guc-file.l:456
2019-12-30 15:27:18.462 CST test@testdb [2224] [local] LOG: 00000: duration: 0.542 ms
2019-12-30 15:27:18.462 CST test@testdb [2224] [local] LOCATION: exec_simple_query, postgres.c:1289
2019-12-30 15:27:36.559 CST test@testdb [5749] [local] LOG: 00000: duration: 0.639 ms
2019-12-30 15:27:36.559 CST test@testdb [5749] [local] LOCATION: exec_simple_query, postgres.c:1289
2019-12-30 15:27:44.470 CST test@testdb [2224] [local] LOG: 00000: duration: 3.592 ms
2019-12-30 15:27:44.470 CST test@testdb [2224] [local] LOCATION: exec_simple_query, postgres.c:1289
2019-12-30 15:27:58.024 CST test@testdb [5749] [local] LOG: 00000: process 5749 still waiting for AccessShareLock on relation 16385 of database 16384 after 1000.615 ms at character 22
2019-12-30 15:27:58.024 CST test@testdb [5749] [local] DETAIL: Process holding the lock: 2224. Wait queue: 5749.
2019-12-30 15:27:58.024 CST test@testdb [5749] [local] LOCATION: ProcSleep, proc.c:1493
...
log_statement
记录哪些语句，可选项包括none, ddl, mod, all。
设置该参数为all，而log_min_duration_statement设置为600
执行SQL
[local:/data/run/test]:5000 test@testdb=# select 1;
?column?
----------
1
(1 row)
[local:/data/run/test]:5000 test@testdb=# select pg_sleep(1);
pg_sleep
----------
(1 row)
虽然select 1;执行得很快，没有超过600ms，但由于设置了该参数为all，因此也会在日志中出现
2019-12-30 15:32:41.934 CST @ [2163] LOG: 00000: received SIGHUP, reloading configuration files
2019-12-30 15:32:41.934 CST @ [2163] LOCATION: SIGHUP_handler, postmaster.c:2635
2019-12-30 15:32:41.939 CST @ [2163] LOG: 00000: parameter "log_min_duration_statement" changed to "600"
2019-12-30 15:32:41.939 CST @ [2163] LOCATION: ProcessConfigFileInternal, guc-file.l:456
2019-12-30 15:32:41.939 CST @ [2163] LOG: 00000: parameter "log_statement" changed to "all"
2019-12-30 15:32:41.939 CST @ [2163] LOCATION: ProcessConfigFileInternal, guc-file.l:456
2019-12-30 15:32:51.932 CST test@testdb [2224] [local] LOG: 00000: statement: select 1;
2019-12-30 15:32:51.932 CST test@testdb [2224] [local] LOCATION: exec_simple_query, postgres.c:1045
2019-12-30 15:32:51.932 CST test@testdb [2224] [local] LOG: 00000: duration: 0.375 ms
2019-12-30 15:32:51.932 CST test@testdb [2224] [local] LOCATION: exec_simple_query, postgres.c:1289
2019-12-30 15:33:02.686 CST test@testdb [2224] [local] LOG: 00000: statement: select pg_sleep(1);
2019-12-30 15:33:02.686 CST test@testdb [2224] [local] LOCATION: exec_simple_query, postgres.c:1045
2019-12-30 15:33:03.691 CST test@testdb [2224] [local] LOG: 00000: duration: 1005.297 ms
2019-12-30 15:33:03.691 CST test@testdb [2224] [local] LOCATION: exec_simple_query, postgres.c:1289
把该参数设置为none，执行同样的SQL，日志输出中只有select pg_sleep(1);
2019-12-30 15:35:06.740 CST @ [2163] LOG: 00000: received SIGHUP, reloading configuration files
2019-12-30 15:35:06.740 CST @ [2163] LOCATION: SIGHUP_handler, postmaster.c:2635
2019-12-30 15:35:06.743 CST @ [2163] LOG: 00000: parameter "log_statement" changed to "none"
2019-12-30 15:35:06.743 CST @ [2163] LOCATION: ProcessConfigFileInternal, guc-file.l:456
2019-12-30 15:35:09.995 CST test@testdb [2224] [local] LOG: 00000: duration: 0.325 ms
2019-12-30 15:35:09.995 CST test@testdb [2224] [local] LOCATION: exec_simple_query, postgres.c:1289
2019-12-30 15:35:12.441 CST test@testdb [2224] [local] LOG: 00000: duration: 1001.645 ms statement: select pg_sleep(1);
2019-12-30 15:35:12.441 CST test@testdb [2224] [local] LOCATION: exec_simple_query, postgres.c:1296
log_replication_commands
是否记录复制命令。
log_temp_files
是否记录大小超过该参数配置大小的临时文件。在执行大批量数据排序或者使用临时表时可以用于诊断。
2019-12-30 15:40:37.992 CST @ [2163] LOG: 00000: received SIGHUP, reloading configuration files
2019-12-30 15:40:37.992 CST @ [2163] LOCATION: SIGHUP_handler, postmaster.c:2635
2019-12-30 15:40:37.993 CST @ [2163] LOG: 00000: parameter "log_replication_commands" changed to "on"
2019-12-30 15:40:37.993 CST @ [2163] LOCATION: ProcessConfigFileInternal, guc-file.l:456
2019-12-30 15:40:37.993 CST @ [2163] LOG: 00000: parameter "log_temp_files" changed to "1024"
2019-12-30 15:40:37.993 CST @ [2163] LOCATION: ProcessConfigFileInternal, guc-file.l:456
###日志输出
2019-12-30 15:42:07.897 CST test@testdb [2224] [local] LOG: 00000: temporary file: path "base/pgsql_tmp/pgsql_tmp2224.4", size 29507584
2019-12-30 15:42:07.897 CST test@testdb [2224] [local] LOCATION: ReportTemporaryFileUsage, fd.c:1285
log_timezone
是否记录时区信息。
到此，相信大家对“分析PostgreSQL日志相关的配置参数log_XXX”有了更深的了解，不妨来实际操作一番吧！这里是创新互联网站，更多相关内容可以进入相关频道进行查询，关注我们，继续学习！
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