Drop Down MenusCSS Drop Down MenuPure CSS Dropdown Menu

PostgresqlDBA interview questions and answers

-

Questions :I have three  tables which contains around 20millions of records. I am planning to update these three tables for all records. Could you suggest me best approaches to meet this, please?
Ans:
1.I think disable index before update ? And autovacuum off,arhvive off if possible.
2.Increase the check point time out
Increase shared buffer or wall beffer if archive enable.
3.Check any parallel option is there.

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 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

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

Postgres Streaming Replication Configuration

-
Primary - Existing Test Server: ======= Hostname: nijam-1 IP Address: 53.99.198.11 Secodary - New Test Server ======== Hostname: nijam-2 IP Address: 53.99.198.12 ===================================================== Step 1. stop the slave server /optt/10.5/bin/pg_ctl -D /DATA stop Step 2. move the slave data directory to backup location: mv /DATA/* /tmp/backup Step 3. change below parameter on master postgresql.conf & pg_hba.conf files . listen_addresses = 'localhost,53.99.198.11' wal_level = replica # minimal, replica, or logical archive_mode = on archive_command = 'cp %p /ARCHIVES/%f' max_wal_senders = 10 wal_keep_segments = 25 On pg_hba.conf: host replication postgres 53.99.198.12/24 trust host replication postgres 53.99.198.11/24 trust Step 4. Restart the master server: /optt/10.5/bin/pg_ctl -D /DATA restart Step 5. taking consistancy backup: psql -c "sele
Read more

vacuumlo - removing large objects orphans from a database PostgreSQL

-
vacuumlo   is a simple utility program that will remove any   “ orphaned ”   large objects from a   PostgreSQL   database. An orphaned large object (LO) is considered to be any LO whose OID does not appear in any   oid   or   lo   data column of the database. OIDs basically give you a built-in, globally unique id for every row,default is on( default_with_oids ( boolean )). If you use this, you may also be interested in the   lo_manage   trigger in the   lo   module.   lo_manage   is useful to try to avoid creating orphaned LOs in the first place. More about lo module  there are two ways to store large objects in the PostgreSQL:   bytea oid and lo  Working process of vacuumlo: First, vacuumlo builds a temporary table which contains all of the OIDs of the large objects in the selected database. It then scans through all columns in the database that are of type oid or lo, and removes matching entries from the temporary table. (Note: only types with these names are con
Read more