postgresql 日志配置

PostgreSQL有3种日志，分别是pg_log（数据库运行日志）、pg_xlog（WAL 日志，即重做日志）、pg_clog（事务提交日志，记录的是事务的元数据）


pg_log默认是关闭的，需要设置参数启用此日志。pg_xlog和pg_clog都是强制打开的，无法关闭。






1.启用pg_log并配置日志参数
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 = info
# 记录执行慢的SQL
log_min_duration_statement = 60
log_checkpoints = on
log_connections = on
log_disconnections = on
log_duration = on
log_line_prefix = '%m'
# 监控数据库中长时间的锁
log_lock_waits = on
# 记录DDL操作
log_statement = 'ddl'


2.重启PostgreSQL即可在$PGDATA/pg_log/ 下看到新生成的日志。

pg_ctl restart -m fast

--日志文件目录   
   日志的目录可以通过参数  log_directory 来设置，下面是我的参数设置。
   log_directory = '/var/applog/pg_log'  
    
[postgres@pg_log]$ ll /var/applog/pg_log    
-rw------- 1 postgres postgres 4.8M Mar 14 23:57 postgresql-2011-03-14_000000.csv
-rw------- 1 postgres postgres    0 Mar 14 00:00 postgresql-2011-03-14_000000.log
-rw------- 1 postgres postgres 294K Mar 15 15:10 postgresql-2011-03-15_000000.csv
-rw------- 1 postgres postgres    0 Mar 15 00:00 postgresql-2011-03-15_000000.log

--CSV日志文件内容
2011-03-15 00:07:03.513 CST,"wapportal","wapportal_216",4137,"172.16.3.43:59356",4d7e361f.1029,3,"idle",2011-03-14 23:37:03 CST,,0,LOG,00000,"disconnection: session time: 0:30:00.086 user=wapportal database=wapportal_216 host=172.16.3.43 port=59356",,,,,,,,,""
2011-03-15 00:07:03.514 CST,,,5173,"",4d7e3d27.1435,1,"",2011-03-15 00:07:03 CST,,0,LOG,00000,"connection received: host=172.16.3.43 port=51135",,,,,,,,,""

   上面两条是 postgresql-2011-03-15_000000.csv 日志文件的部分内容 ,由于日志文件的可读性
 较差，于是可以通过下面方法将CSV日志导入到数据库表里。详细如下

 
将CSV日志导入数据库表里   
1--调整参数
log_destination = 'csvlog'
logging_collector = on

    这两个参数修改后，PG SERVER 需要重启。

2--创建日志记录表
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;

    备注：创建日志表 postgres_log 用来保存 CSV日志数据。

3--导入操作系统 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

      备注：文件形式导入导出数据需要以超级用户 postgres 连接到目标库。

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 :    SELECT cit
yname,province,the_geom as the_geom FROM china_city   
.......
    
       为了显示方便，上面只取一条记录。