Drop Down MenusCSS Drop Down MenuPure CSS Dropdown Menu

PostgreSQL Replication slot

-

Configuration

You can create a replication slot like this:
postgres=# SELECT * FROM pg_create_physical_replication_slot('node_a_slot');
  slot_name  | xlog_position
-------------+---------------
 node_a_slot |

postgres=# SELECT * FROM pg_replication_slots;
  slot_name  | slot_type | datoid | database | active | xmin | restart_lsn | confirmed_flush_lsn
-------------+-----------+--------+----------+--------+------+-------------+---------------------
 node_a_slot | physical  |        |          | f      |      |             |
(1 row)
To configure the standby to use this slot, primary_slot_name should be configured in the standby's recovery.conf. Here is a simple example:
standby_mode = 'on'
primary_conninfo = 'host=192.168.1.50 port=5432 user=foo password=foopass'
primary_slot_name = 'node_a_slot'

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

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

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

7 Steps to configure BDR replication in postgresql

-
Image
 The  BDR  (Bi-Directional Replication) project adds multi-master replication to PostgreSQL 9.4.  Postgres-BDR has a lower impact on the masters(s) than trigger-based replication solutions. There is no write-amplification, as it does not require triggers to write to queue tables in order to replicate writes.   Here We are using  postgres version 9.4.12 and bdr version 1.0.2. for configuring  multi master replication . Simply Following 7 steps you can configure the multi master replication in postgresql. To download the bdr in below link. .   https://github.com/2ndQuadrant/bdr/archive/bdr-pg/REL9_4_12-1.tar.gz $ tar -xzvf REL9_4_12-1.tar.gz $ wget https://github.com/2ndQuadrant/bdr/archive/bdr-plugin/1.0.2.tar.gz $ tar -xzvf 1.0.2.tar.gz 1. To install BDR. $ cd ~/bdr-bdr-pg-REL9_4_12-1 $ ./configure --prefix=/usr/lib/postgresql/9.4 --enable-debug --with-openssl $ make -j4 -s install-world $ cd ~/bdr-bdr-plugin-1.0.2 $ PATH=/usr/lib/postgresql/9.4/bin:"$PATH" ./c
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