postgreSQL9.3日志配置
pg的日志配置选项很多，默认的情况下pg只是记录了启动停止的信息。在postgresql.conf配置文件中，你可以配置日志记录在哪里，日志记录什么，日志什么时候记录。如下面的是我自己测试的设置
# - When to Log -
client_min_messages = notice # values in order of decreasing detail:
# debug5
# debug4
# debug3
# debug2
# debug1
# log
# notice
# warning
# error
log_min_messages = warning # values in order of decreasing detail:
# debug5
# debug4
# debug3
# debug2
# debug1
# info
# notice
# warning
# error
# log
# fatal
# panic
log_min_error_statement = error # values in order of decreasing detail:
# debug5
# debug4
# debug3
# debug2
# debug1
# info
# notice
# warning
# error
# log
# fatal
# panic (effectively off)
log_min_duration_statement = 0 # -1 is disabled, 0 logs all statements
# and their durations, > 0 logs only
# statements running at least this number
# of milliseconds
# - What to Log -
#debug_print_parse = off
#debug_print_rewritten = off
debug_print_plan = on
#debug_pretty_print = on
#log_checkpoints = off
log_connections = on
log_disconnections = on
#log_duration = off
#log_error_verbosity = default # terse, default, or verbose messages
#log_hostname = off
log_line_prefix = '%d%p%c%t ' # special values:
# %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
# %% = '%'
# e.g. '<%u%%%d> '
#log_lock_waits = off # log lock waits >= deadlock_timeout
#log_statement = 'none' # none, ddl, mod, all
#log_temp_files = -1 # log temporary files equal or larger
# than the specified size in kilobytes;
# -1 disables, 0 logs all temp files
log_timezone = 'Asia/Hong_Kong'
在log_line_prefix中记录了数据库名字，进程id,会话id,时间。
log_connection记录了连接的信息等等，这些都是可以按自己的需要来指定的。
下面测试将日志放到csv文件中
log_destination = 'csvlog' # Valid values are combinations of
# stderr, csvlog, syslog, and eventlog,
# depending on platform. csvlog
# requires logging_collector to be on.
# This is used when logging to stderr:
logging_collector = on # Enable capturing of stderr and csvlog
# into log files. Required to be on for
# csvlogs.
# (change requires restart)
# These are only used if logging_collector is on:
log_directory = 'D:\\PostgreSQL\\9.3\\data\\logs' # directory where log files are written,
# can be absolute or relative to PGDATA
log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log' # log file name pattern,
设置这几个参数后，重启db就可以生成csv格式的日志了，这种日志可以方便的将日志文件放入到数据库的表中。下面创建日志表
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) );
使用copy将日志文件拷贝到表中
copy postgres_log from 'D:\\PostgreSQL\\9.3\\data\\logs\\postgresql-2014-11-17_210250.csv' with csv;
拷贝表到文件中：copy customer to 'D:\\test2.txt';
这个copy在表和文件中移动数据很方便。
日志配置推荐设置的参数
log_line_prefix='%t:%r:%u@%d:[%p]:' 记录日志的内容
log_statement记录日志的类型
log_min_duration_statement记录超过多长时间的sql