Drop Down MenusCSS Drop Down MenuPure CSS Dropdown Menu

Postgresql ERROR: relation "pg_catalog" does not exist because pg_catalog is a schema

-
I couldn't find anything in the postgresql manual as how to view its
 content. SELECT does not seem to work.
       
 What's the exact command and error message?
netilla=#  \dn
        List of schemas
        Name        |  Owner
 --------------------+----------
 information_schema | postgres
 pg_catalog         | postgres
 pg_toast           | postgres
 public             | postgres
 (4 rows)

 netilla=# select * from pg_catalog;
 ERROR:  relation "pg_catalog" does not exist
     
   
That would be because pg_catalog is a schema; you can't select from it.
If you want to see what's in there, use \dS.

Comments

Post a Comment

Popular posts from this blog

How to find the server is whether standby (slave) or primary(master) in Postgresql replication ?

-
Method 1 You can check the mode of the server using "pg_controldata". [pgsql@test~]$ pg_controldata /usr/local/pgsql/data84/ Database cluster state: in archive recovery --> This is Standby Database Database cluster state: in production --> This is Production Database [Master] Method 2 You can use pg_is_in_recovery() which returns True if recovery is still in progress(so the server is running in standby mode or slave) postgres=# select pg_is_in_recovery(); pg_is_in_recovery ------------------- t (1 row) If Return    false   so the server is running in primary mode or master postgres=# select pg_is_in_recovery(); pg_is_in_recovery ------------------- f (1 row)
Read more

How to Return a Result Set from a PostgreSQL Stored Procedure

-
Image
Both stored procedures and user-defined functions are created with CREATE FUNCTION statement in PostgreSQL. To return one or more result sets (cursors in terms of PostgreSQL), you have to use  refcursor  return type. Quick Example : -- Procedure that returns a single result set (cursor) CREATE OR REPLACE FUNCTION show_cities ( ) RETURNS refcursor AS $$ DECLARE ref refcursor; -- Declare a cursor variable BEGIN OPEN ref FOR SELECT city , state FROM cities; -- Open a cursor RETURN ref; -- Return the cursor to the caller END ; $$ LANGUAGE plpgsql; Overview : Return Multiple Result Sets Cursor Lifetime Until the  end  of transaction Auto-commit Must be  off Transaction must be active so the caller can see a result set Important Note : The cursor remains open until the end of transaction, and since PostgreSQL works
Read more

PostgreSQL New version upgrade

-
Image
In this blog we are going to upgrade the postgresql server from 9.5 to 11.3 . We are upgraded the postgres server by using pg_upgrade utility as well as logical backup method , you can follow anyone  of the method . Collect the server details before proceed  upgrade activity.  Title PostgreSQL VERSION 9.5 PostgreSQL VERSION 11.3 DATA DIRECTORY /data_9.5 /data_11.3 BIN path /opt/postgresql/9.5 /opt/postgresql/11.3 PORT 50000 5432 PREREQUEST : =========== Step 1. Check the application backend connection if any application connected , Disconnect the application from DB server. Below command will be helpful to checking backend connection : template1=# select datname, count(*) from pg_stat_activity group by datname; datname | count -----------+------- testdb | 1 template1 | 0 (2 rows) template1=# select datname, numbackends from pg_stat_database; datname | numbackends -----------+------------- testdb | 1 template1 | 0 templ
Read more

How to Get Table Size, Database Size, Indexes Size, schema Size, Tablespace Size, column Size in PostgreSQL Database

-
In this post, I am sharing few important function for finding the size of database, table and index in PostgreSQL. Finding object size in postgresql database is very important and common. Is it very useful to know the exact size occupied by the object at the tablespace. The object size in the following scripts is in GB. The scripts have been formatted to work very easily with PUTTY SQL Editor. 1. Checking table size excluding table dependency: SELECT pg_size_pretty(pg_relation_size('mhrordhu_shk.mut_kharedi_audit')); pg_size_pretty ---------------- 238 MB (1 row) 2. Checking table size including table dependency: SELECT pg_size_pretty(pg_total_relation_size('mhrordhu_shk.mut_kharedi_audit')); pg_size_pretty ---------------- 268 MB (1 row) 3. Finding individual postgresql database size SELECT pg_size_pretty(pg_database_size('db_name')); 4. Finding individual table size for postgresql database -including dependency index: SELECT pg_size_pretty(pg_total_rel
Read more

Linux ctime,mtime,atime,cmin,amin,mmin

-
Unix and therefore Linux uses (at least) 3 different timestamps on modern file systems (see File systems Table for info) in order to date any files. You can use these information to search for files, check logs, manage your backup and more… that’s why it is a must  for any sysadmin to clearly understand this mechanism. This page is aimed at exposing basics knowledge to understand and use files timestamps. 1) Definitions Here are some time stamps related definitions. 1.1 atime This is the Access time : atime is updated whenever file’s data is accessed (a read, write or any other access); this could be done by a system process, interactively by CLI or by a script. 1.2 mtime This is the Modification time : mtime is updated whenever the file’s content changes. This time stamp is not updated by a change of files permissions (e.g : through a chown command). It is usually used for tracking the file content changes (see the Linux time related tools section below for more inf
Read more