Questions tagged [master-slave-replication]

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Trying to understand SHOW SLAVE STATUS in MySQL

I have a Master-Slave replication setup and it looks like that it is running fine. Below is a result of SHOW SLAVE STATUS command: show slave STATUS\G; *************************** 1. row *************...
newbie14's user avatar
  • 969
6 votes
1 answer
3k views

Queries running very slowly in Amazon RDS PostgreSQL read-replica

We have been maintaining a project which has both web and mobile application platform. The backend of the project is developed in Django 1.10 and deployed in AWS. At the beginning, when there were ...
Mahmud Al-Noor's user avatar
5 votes
3 answers
5k views

MySQL Master/Slave replication on same VM instance?

I'm fairly new to databases so I hope this isn't a silly question! Is it possible to set up master/slave replication on the SAME server? I understand there are not any advantages to this in terms of ...
Stephen91's user avatar
  • 113
5 votes
1 answer
928 views

Why does mysqldump stop the slave SQL thread for the entire backup?

I realized recently that I was using --master-data to dump a backup from a replication slave when what I really wanted was --dump-slave. After switching to --dump-slave, I see that mysqldump will stop ...
Christopher Schultz's user avatar
4 votes
3 answers
2k views

In replication A->B->C, can A be binlog_format=STATEMENT and B be binlog_format=ROW?

I have replication setup between an on-prem MySQL 5.6 server (A) to another on-prem MySQL 5.6 server (B). I was setting up an AWS DMS instance (C) that I wanted to migrate and then replicate. It ...
Aaron R.'s user avatar
  • 143
4 votes
2 answers
6k views

MySQL slave not able to execute long running update query

I am running a Master-slave replication servers of MySQL. As part of clean up of old data, i ran a delete query which deletes huge number of records from the database. It ran fine on Master server but ...
Ruchit Rami's user avatar
4 votes
3 answers
31k views

PostgreSQL service start failed on CentOS 7

Installed PostgreSQL using: sudo yum install postgresql-server postgresql-contrib PostgreSQL version: 9.2.18 When start service: sudo service postgresql start Got error: Redirecting to /bin/...
cloud_cloud's user avatar
4 votes
1 answer
6k views

Service mongod fails after adding security.keyFile in config file

My mongo.conf: # where to write logging data. systemLog: destination: file logAppend: true path: /var/log/mongodb/mongod.log # Where and how to store data. storage: dbPath: /var/lib/mongo ...
Abdul Moiz's user avatar
4 votes
2 answers
5k views

How to free up hard drive space after deleting millions upon millions of records in mariadb

We have an application where we are receiving information seconds apart, we record this information in a table that we call events, which currently weighs 240 GB, this is the largest we have so far. ...
Blanca Rodriguez's user avatar
4 votes
0 answers
653 views

MySQL replication - Follower stuck and behind

I understand there are lots of similar problems and threads but non of those solution helped me. Please read through the thread I will try to give as much information as possible: I have setup a ...
Sisir's user avatar
  • 141
4 votes
0 answers
696 views

How to get the Slave commit timestamp using MySql replication?

I've been looking for ways to collect information about the replication delays on MySql 8. I found an alternative solution, but I imagine there's a more straightforward way to do that. By reading its ...
Wilson Neto's user avatar
4 votes
1 answer
840 views

Can PostgreSQL slave server act as master for a new database?

My question is somewhat related to: https://stackoverflow.com/questions/19331577/does-postgres-replication-native-support-per-database-level-replication We have master-slave replication set up on ...
arun's user avatar
  • 145
4 votes
0 answers
7k views

Slave is not configured or failed to initialize properly. You must at least set --server-id to enable either a master or a slave

I am trying to setup multi source replication. In my slave I have defined following two properties in its configuration file. master-info-repository=table relay-log-info-repository=table These ...
Frank Martin's user avatar
3 votes
2 answers
3k views

How to avoid replication lag in case all writes on master and reads on replica?

I have stuck with the replication lag problem. I am trying to refactor my DB infrastructure. The first step was read-write split. I used ProxySQL то implement it. Now I have masterDb where all INSERT ...
Volodymyr Bilovus's user avatar
3 votes
2 answers
9k views

Change host IP of master in mysql replication

I have one master and one slave. Suppose IP of master is changed but the physical server is same. Now I want to update the new IP (of the master) at the slave server. At the slave server ...
srvnk's user avatar
  • 91
3 votes
1 answer
3k views

MySQL 8.016 master with MariaDB 10.2 slave on AWS RDS, Character set '#255' is not a compiled character set

I have a MySQL 8.016 master and a MariaDB 10.2 slave, both running on AWS RDS. This was working perfectly until today, when I figured I wanted to do chain replication instead, like this MySQL 8.016 ->...
Magnus's user avatar
  • 135
3 votes
2 answers
6k views

org.postgresql.util.PSQLException: ERROR: canceling statement due to conflict with recovery

I currently have a PostgreSQL slave node that is presenting problems, that don't arise in the master node. Seems to be related with the node sync process. Complete stacktrace: org.postgresql.util....
Gonzalo Vasquez's user avatar
3 votes
1 answer
6k views

Postgres max_wal_size and wal_keep_size parameter

I am setting up Postgres v14 database. I have a question related to the max_wal_size and wal_keep_size parameters. According to the documentation: max_wal_size ⇒ Maximum size to let the WAL grow ...
dsingh's user avatar
  • 131
3 votes
3 answers
3k views

What does this error mean "A slave with the same server_uuid/server_id as this slave has connected to the master;"?

Upon searching for this, the main cause of this error is usually when using snapshots or cloning the machine. But I did not do this. I perform mysqldump --master-data=2 on the master then restore the ...
JRA's user avatar
  • 129
3 votes
2 answers
287 views

MySQL chain replication timing of writes on first slave

With a MySQL chain replication setup, e.g. M1->S1->S2, what exactly is the order of operations for writing to the first slave? Is the binary log from the master simply streamed directly through ...
Matt S's user avatar
  • 133
3 votes
1 answer
3k views

MySQL Replication binary relay logs transfer too slowly

Master server MySQL 5.6.28 Ubuntu 14.04 8 core CPU Slave server Slave: MySQL 5.7.22 Ubuntu 18.04 16 core CPU Both of them have 64GB of RAM and plenty of disk space. What I did up to this ...
Nick Zinger's user avatar
3 votes
1 answer
4k views

mariadb Unknown system variable 'server_uuid'

Im trying to setup replication between mariadb(10.1.31-MariaDB - MASTER) and mysql(5.7.12-log - SLAVE). After executed the start slave, I got the below error. Fatal error: The slave I/O thread ...
TheDataGuy's user avatar
  • 1,910
3 votes
1 answer
2k views

How does one scale out with master-slave replication?

To my understanding, a master-slave replication might be set up where clients can read from multiple databases. However, they can only write to the master. I believe this helps guarantee ACIDity. I ...
dthree's user avatar
  • 261
3 votes
0 answers
2k views

Got fatal error 1236 from master when reading data from binary log

I am trying to do a MySQL failover, in some situations I endup with broken replication. Any idea what could be the cause of it ? Background Needed to perform a host updates on master host. Hence ...
RobinHood's user avatar
3 votes
0 answers
843 views

RESET MASTER; does not reset GTID_EXECUTED

I'm trying to get replication up and running between two kubernetes pods, and am getting the dreaded @@GLOBAL.GTID_PURGED can only be set when @@GLOBAL.GTID_EXECUTED is empty. error. root@central-vm:~...
RonJohn's user avatar
  • 606
3 votes
1 answer
441 views

Can I stop replication of create/drop index statement on one slave of Mysql 5.6?

I have this cluster where master and slave uses same indexes but one of the slaves has some extra indexes (large machine which runs some analytics queries). So I have to maintain two sets of indexes. ...
chinmaygupta28's user avatar
3 votes
0 answers
557 views

Replication doesn't resume once it fails to connect

We have MySQL replication running for our application. Right now the slave fails to resume if it fails to connect to the server for some time. We get the error below: [ERROR] Slave I/O: error ...
Mritunjay's user avatar
3 votes
2 answers
64 views

How do I create a MySQL slave server of a bunch of MyISAM databases on a master

I have a MySQL master server and slave became corrupt because of space issues on the master. Binary logs are potentially corrupt and I don't trust them. The databases are using MyISAM tables. I want ...
flickerfly's user avatar
2 votes
2 answers
3k views

Post Mortem Analysis: PostgreSQL replication failed

We have a PostgreSQL 9.4.9 production server which was replicating to a slave instance, but today I discovered that the instance is out of sync! The obvious actions would be to recreate the slave, ...
Gonzalo Vasquez's user avatar
2 votes
1 answer
1k views

Can we replicate or restrict specific databases in MongoDB

In MySQL, we are having replicate-do-db/replicate-ignore-db during replication, where we can replicate or restrict specific databases from Master to Slave. In the similar way, is there any specific ...
Phanindra's user avatar
  • 1,007
2 votes
3 answers
3k views

SELECT from slave and INSERT into master in MySQL

I'm using PHP/Laravel and MySQL databases. Briefly, I want to use slave databases for reads and master database for writes. What Laravel config, Laravel package, or database tool do you suggest to ...
Milad Rahimi's user avatar
2 votes
1 answer
3k views

Postgresql - increase WAL retention to avoid slave go out of sync with master

I've setup a master / slave Postgresql (13.4) group, 1 master and 1 slave, using WAL warm standby. (refer: https://postgresql.org/docs/current/warm-standby.html#STANDBY-SERVER-SETUP) The slave gone ...
Eric's user avatar
  • 253
2 votes
1 answer
4k views

Is it possible to configure pgbouncer to distribute queries among master and slave?

We have master (write-read) and slave (readonly) Postgres 10 databases. Slave is online replication from master. Now our application (c# webapi) connects to master only directly. We want to execute ...
Doctor Coder's user avatar
2 votes
1 answer
5k views

MySQL Replication Slave Status OK but Data inconsistent

We are using MySQL 5.7, and have a Master and 3 Slave servers replication setup. All the 4 servers are dedicated for MySQL use only, and belong to the same data-center, connected over Private Network. ...
Madhur Bhaiya's user avatar
2 votes
1 answer
617 views

Fix mysql replication crashed due to underlying storage corruption

we have critical database server running on two virtual machines. one virtual machine crashed due to underlying storage problem and we had to move it to different storage medium and recover the xfs ...
rafalefighter's user avatar
2 votes
2 answers
6k views

MySql replication failed with error 1236 data position > file size with relay-bin file not increasing

My slave machine reset and now on SLAVE SHOW STATUS\G I have the error: Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: 'Client requested master to start ...
Dug's user avatar
  • 19
2 votes
1 answer
87 views

Options for having same tables in 2 different data bases

I need to know what options I have for my next problem: I have 2 databases (sql server 2012) first for an ERP second for an website For the website's database, I want to use a table (customer) ...
Ionut P.'s user avatar
2 votes
1 answer
706 views

Restart master in physical replication

I have 2 servers involving master-slave replication (physical replication). I see the replication using select * from pg_replication_slots; there is a record saying : user : rep_user` application : ...
padjee's user avatar
  • 167
2 votes
2 answers
1k views

What is the maximum latency / distance mysql replication can tolerate without having errors or wrong data?

I have two machines in a master - slave replication. I want to know if they are in two seperate places e.g. London, England and Tokyo, Japan are there going to be any latency issues. What exactly is ...
Malazzar's user avatar
2 votes
1 answer
5k views

Can I use MariaDB as a replication slave for MySQL?

I've been a MySQL user/administrator for many years and I've been considering a switch to MariaDB. We have a statement-replicated setup with a MySQL slave and I've been thinking that one way to ease-...
Christopher Schultz's user avatar
2 votes
3 answers
1k views

Seconds_Behind_Master high even though Read_Master_Log_Pos and Exec_Master_Log_Pos are very close

From what I understand from https://dev.mysql.com/doc/refman/5.7/en/show-slave-status.html, seconds_behind_master is the difference in the timestamp of where the IO thread is currently writing in the ...
nikhil vavs's user avatar
2 votes
3 answers
335 views

Why is it not a good idea to use MariaDB's extra_port for replication?

MariaDB has an extra_port for administrative access that helps in cases the thread pool or main port is locked up. MariaDB's documentation says it's use case is primarily administrative access and it ...
wedi's user avatar
  • 121
2 votes
1 answer
2k views

Can a MySQL 5.6 master replicate to a 5.7 slave, which in turn replicates to a MySQL 8 slave?

According to the docs, "MySQL supports replication from one release series to the next higher release series. For example, you can replicate from a master running MySQL 5.6 to a slave running MySQL 5....
timetofly's user avatar
  • 203
2 votes
1 answer
494 views

Master mysq8 slave Mariadb 10.3 Error 22

Master (mysql Ver 8.0.16) Slave (mysql Ver 15.1 Distrib 10.3.15-MariaDB) I have this error Error 'Character set '#255' is not a compiled character set and is not specified in the '/usr/share/...
Goran Siriev's user avatar
2 votes
2 answers
896 views

Issue with Time Zone while migrating MySQL on-premises DB to AWS RDS

I am having MySQL 5.6 database with PST time format in on-premises server. Now we are willing to migrate the database to RDS. For this, we have taken backup from physical server and restored in RDS ...
Phanindra's user avatar
  • 1,007
2 votes
1 answer
1k views

Master-slave replication doesn't work on PostgreSQL 9.6

I tried to create a master/slave configuration with two servers and Postgres 9.6 I modified master and slave postgresql.conf in /etc/postgresql/9.6/main Same for master and slave: data_directory = '...
Hydrazounet's user avatar
2 votes
1 answer
935 views

Why has deadlock behaviour changed between MariaDB 10.1.22 and 10.2.14?

Since upgrading MariaDB 10.1.22 to 10.2.14 our MariaDB slaves are encountering deadlocks that are not handled in less than 600 seconds thus the classic semaphore decision to crash the server. The ...
SAK's user avatar
  • 301
2 votes
1 answer
5k views

Mysql replication broken due to 'Duplicate entry' with error code 1062 on slave server

Mysql Slave replication was working fine, but suddenly it has crashed due to duplicate entries error The slave SQL thread stops due to duplicate entries in MySQL DB, which I have kept in ...
jugadengg's user avatar
2 votes
1 answer
3k views

how can be changed hot_standby parameter on postgres 9.6 aws/rds?

I have a postgres solution on aws/rds with a master and a read replica. master slave hot_standby on on transaction_read_only on on ...
vcarusi's user avatar
  • 21
2 votes
1 answer
794 views

Fetch just inserted data in master/slave model?

Say I have MySQL master DB(used for updates) and corresponding Slave DB(used for reads). Now user inserts the data into MASTER through application(java), just after insertion he tries to retrieve the ...
emilly's user avatar
  • 175

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