使用 file_fdw 读取 pglog，以便实时监控日志。

创建 extension

CREATE EXTENSION file_fdw;

创建 server

CREATE SERVER file_fdw_server FOREIGN DATA WRAPPER file_fdw;

获取最新日志文件

select t00.*
from (select t1.file,t1.file_ls,(pg_stat_file(t1.file)).modification as last_update_time,round( ((pg_stat_file(t1.file)).size)/1024/1024*1.0,1) as log_size_mbfrom (select dir||'/'||pg_ls_dir(t0.dir) as file,pg_ls_dir(t0.dir) as file_lsfrom ( select setting as dir from pg_settings where name='log_directory') t0) t1 where 1=1order by (pg_stat_file(file)).modification desc) t00
where 1=1and t00.file_ls like '%.csv'
limit 1
;

创建外部表

select name,setting
from pg_settings where name ~ 'log';CREATE FOREIGN TABLE pglog_current (  log_time timestamp(3) without 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)
server file_fdw_server
options(filename '/var/log/postgresql/postgresql-2017-08-29.csv',format 'csv')
;

查询外部表

select count(1)
from pglog_current
where 1=1
;select plc.*
from pglog_current plc
where 1=1
order by plc.log_time
;

可以和德哥一样写个存储过程来判断和创建。

参考：
http://blog.163.com/digoal@126/blog/static/16387704020121023105322442/
https://www.postgresql.org/docs/current/static/sql-createforeigntable.html
https://www.postgresql.org/docs/current/static/file-fdw.html