postgresql9.5.9相關的日志檔案介紹

一.PostgreSQL有3種日志，分别是pg_log（資料庫運作日志）、pg_xlog（WAL 日志，即重做日志）、pg_clog（事務送出日志，記錄的是事務的中繼資料）

pg_log預設是關閉的，需要設定參數啟用此日志。pg_xlog和pg_clog都是強制打開的，無法關閉

1.啟用pg_log并配置日志參數

log_destination = 'csvlog'

logging_collector = on

log_directory = 'pg_log'

log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log'

log_rotation_age = 1d

log_rotation_size = 100MB

log_min_messages = warning

參數解釋：

log_directory = '/data/pgsql086/log'

這個參數隻能在postgresql.conf檔案中被設定。它決定存放資料庫運作日志檔案的目錄。預設值是pg_log。可以是絕對路徑，也可是相對路徑（相對于資料庫檔案所在的路徑）。

它決定資料庫運作日志檔案的名稱。預設值是postgresql-%Y-%m-%d_%H%M%S.log。它的值可以包含%Y、%m、%d、%H、%M和%S這樣的字元串，分别表示年、月、日、小時、分和秒。 如果參數的值中沒有指定時間資訊（沒有出現%Y、%m、%d、%H、%M和%S中的任何一個），系統會自動在log_filename值的末尾加上檔案建立的時間作為檔案名，例如，如果log_filename的值是 server_log，那麼在Sun Aug 29 19:02:33 2004 MST被建立的日志檔案的名稱将是server_log.1093827753，1093827753是Sun Aug 29 19:02:33 2004 MST在資料庫内部的表示形式。這個參數隻能在postgresql.conf檔案中被設定。

單個日志檔案的生存期，預設1天，在日志檔案大小沒有達到log_rotation_size時，一天隻生成一個日志檔案

log_rotation_size = 10MB 

這個參數隻能在postgresql.conf檔案中被設定。單個日志檔案的大小，如果時間沒有超過log_rotation_age，一個日志檔案最大隻能到10M，否則将新生成一個日志檔案。

log_min_messages = warning  預設是warning ，

控制寫到資料庫日志檔案中的消息的級别。合法的取值是DEBUG5、DEBUG4、DEBUG3、DEBUG2、DEBUG1、INFO、NOTICE、WARNING、ERROR、 LOG、FATAL和PANIC，每個級别都包含排在它後面的所有級别中的資訊。級别越高，資料庫運作日志中記錄的消息就越多。

重新開機postgresql服務：

[postgres@cacti log]$ pg_ctl status

pg_ctl: no server running

[postgres@cacti log]$ pg_ctl start

server starting

[postgres@cacti log]$ LOG:  redirecting log output to logging collector process

HINT:  Future log output will appear in directory "/data/pgsql086/log".

[postgres@cacti log]$ ll /data/pgsql086/log/*

-rw-------. 1 postgres postgres 30477 Nov  2 12:01 /data/pgsql086/log/postgres.log

-rw-------. 1 postgres postgres   794 Nov  2 15:14 /data/pgsql086/log/postgresql-2017-11-02_151410.csv

-rw-------. 1 postgres postgres    96 Nov  2 15:14 /data/pgsql086/log/postgresql-2017-11-02_151410.log

[postgres@cacti log]$ tailf /data/pgsql086/log/postgresql-2017-11-02_151410.csv

2017-11-02 15:14:10.385 CST,,,21315,,59fac5c2.5343,1,,2017-11-02 15:14:10 CST,,0,LOG,00000,"ending log output to stderr",,"Future log output will go to log destination ""csvlog"".",,,,,,,""

2017-11-02 15:14:10.387 CST,,,21317,,59fac5c2.5345,1,,2017-11-02 15:14:10 CST,,0,LOG,00000,"database system was shut down at 2017-11-02 15:13:29 CST",,,,,,,,,""

2017-11-02 15:14:10.389 CST,,,21317,,59fac5c2.5345,2,,2017-11-02 15:14:10 CST,,0,LOG,00000,"MultiXact member wraparound protections are now enabled",,,,,,,,,""

2017-11-02 15:14:10.392 CST,,,21321,,59fac5c2.5349,1,,2017-11-02 15:14:10 CST,,0,LOG,00000,"autovacuum launcher started",,,,,,,,,""

2017-11-02 15:14:10.392 CST,,,21315,,59fac5c2.5343,2,,2017-11-02 15:14:10 CST,,0,LOG,00000,"database system is ready to accept connections",,,,,,,,,""

2017-11-02 15:14:43.211 CST,,,21338,"127.0.0.1:33506",59fac5e3.535a,1,"",2017-11-02 15:14:43 CST,,0,LOG,00000,"connection received: host=127.0.0.1 port=33506",,,,,,,,,""

2017-11-02 15:14:43.212 CST,"postgres","postgres",21338,"127.0.0.1:33506",59fac5e3.535a,2,"authentication",2017-11-02 15:14:43 CST,2/5,0,LOG,00000,"connection authorized: user=postgres database=postgres",,,,,,,,,""

2017-11-02 15:14:55.416 CST,,,21339,"127.0.0.1:33507",59fac5ef.535b,1,"",2017-11-02 15:14:55 CST,,0,LOG,00000,"connection received: host=127.0.0.1 port=33507",,,,,,,,,""

2017-11-02 15:14:55.417 CST,"postgres","testdb03",21339,"127.0.0.1:33507",59fac5ef.535b,2,"authentication",2017-11-02 15:14:55 CST,3/1,0,LOG,00000,"connection authorized: user=postgres database=testdb03",,,,,,,,,""

2017-11-02 15:15:26.873 CST,"postgres","testdb03",21339,"127.0.0.1:33507",59fac5ef.535b,3,"SELECT",2017-11-02 15:14:55 CST,3/4,0,ERROR,42P01,"relation ""weather1"" does not exist",,,,,,"select * from weather1;",15,,"psql.bin"

上面兩條是 postgresql-2011-03-15_000000.csv 日志檔案的部分内容 ,由于日志檔案的可讀性

 較差，于是可以通過下面方法将CSV日志導入到資料庫表裡。詳細如下

将CSV日志導入資料庫表裡   

1--調整參數

    這兩個參數修改後，PG SERVER 需要重新開機。

2--建立日志記錄表

CREATE TABLE postgres_log

(

  log_time timestamp(3) with time zone,

  user_name text,

  database_name text,

  process_id integer,

  connection_from text,

  session_id text,

  session_line_num bigint,

  command_tag text,

  session_start_time timestamp with time zone,

  virtual_transaction_id text,

  transaction_id bigint,

  error_severity text,

  sql_state_code text,

  message text,

  detail text,

  hint text,

  internal_query text,

  internal_query_pos integer,

  context text,

  query text,

  query_pos integer,

  location text,

  application_name text,

  PRIMARY KEY (session_id, session_line_num)

);

NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "postgres_log_pkey" for table "postgres_log"

CREATE TABLE;

    備注：建立日志表 postgres_log 用來儲存 CSV日志資料。

3--導入作業系統 csv 日志到表 postgres_log 表

skytf=# copy skytf.postgres_log from '/var/applog/pg_log/postgresql-2011-03-14_000000.csv' with csv;

COPY 26031

skytf=# copy skytf.postgres_log from '/var/applog/pg_log/postgresql-2011-03-15_000000.csv' with csv;

COPY 1297

      備注：檔案形式導入導出資料需要以超級使用者 postgres 連接配接到目标庫。

4--常用日志分析sql

skytf=# select min(log_time),max(log_time) from skytf.postgres_log;

            min             |            max             

----------------------------+----------------------------

 2011-03-14 14:04:07.275+08 | 2011-03-16 05:04:34.427+08

(1 row)

skytf=> select log_time,database_name,user_name,application_name,message from postgres_log where message like '%duration%';

          log_time          | database_name | user_name | application_name |                                                    mess

age                                                    

----------------------------+---------------+-----------+------------------+--------------------------------------------------------

-------------------------------------------------------

 2011-03-15 00:23:38.957+08 | db_lbs        | lbs       |                  | duration: 1297.440 ms  execute <unnamed>:    SELECT cit

yname,province,the_geom as the_geom FROM china_city   

.......

      為了顯示友善，上面隻取一條記錄。

提示：

隻要重新開機資料庫，就會産生新的postgresql運作日志檔案，同時postgresql-2017-11-02_151410.csv隻記錄錯誤日志

[postgres@cacti log]$ pg_ctl stop

waiting for server to shut down.... done

server stopped

[postgres@cacti log]$ ll /data/pgsql086/log/

total 56

-rw-------. 1 postgres postgres 30477 Nov  2 12:01 postgres.log

-rw-------. 1 postgres postgres  4971 Nov  2 15:37 postgresql-2017-11-02_151410.csv

-rw-------. 1 postgres postgres    96 Nov  2 15:14 postgresql-2017-11-02_151410.log

-rw-------. 1 postgres postgres   794 Nov  2 15:37 postgresql-2017-11-02_153751.csv

-rw-------. 1 postgres postgres    96 Nov  2 15:37 postgresql-2017-11-02_153751.log

2.記錄執行慢的SQL

log_min_duration_statement = 60

log_checkpoints = on

log_connections = on

log_disconnections = on

log_duration = on

log_line_prefix = '%m'

# 監控資料庫中長時間的鎖

log_lock_waits = on

# 記錄DDL操作

log_statement = 'ddl'

參考博文：

<a href="http://www.cnblogs.com/alianbog/p/5596921.html" target="_blank">http://www.cnblogs.com/alianbog/p/5596921.html</a>

http://blog.csdn.net/shanzhizi/article/details/47616645

 本文轉自 wjw555 51CTO部落格，原文連結:http://blog.51cto.com/wujianwei/1978449