编辑数据目录中的postgresql.conf参数文件，我的数据目录是/usr/local/pgsql/data
vi postgresql.conf
找到如下内容：
...
#------------------------------------------------------------------------------
# ERROR REPORTING AND LOGGING
#------------------------------------------------------------------------------
# - Where to Log -
#log_destination = 'stderr' # 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 = off # 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 = 'pg_log' # 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,
# can include strftime() escapes
#log_file_mode = 0600 # creation mode for log files,
# begin with 0 to use octal notation
#log_truncate_on_rotation = off # If on, an existing log file with the
#log_rotation_age = 1d # Automatic rotation of logfiles will
# happen after that time. 0 disables.
#log_rotation_size = 10MB # Automatic rotation of logfiles will
...
日志收集功能在大部分情况下是需要打开的，所以设置为：
logging_collector = on
日志目录可以使用默认目录，也可以自行修改，一般选择默认目录就可以了：
log_directory = 'pg_log'
日志文件模式，一般选择默认就可以：
log_file_mode = 0600
日志保存周期及切换方式可以采用如下几种方案：
(1)每天生成新的日志文件
log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log'
log_truncate_on_rotation = off
log_rotation_age = 1d
log_rotation_size = 0
(2)每当日志文件满10M时，进行切换
log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log'
log_truncate_on_rotation = off
log_rotation_age = 0
log_rotation_size = 10M
(3)日志保存周期为7天，循环覆盖
log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log'
log_truncate_on_rotation = on
log_rotation_age = 1d
log_rotation_size = 0