Bi-directional replication for the same MySQL table
AppA stores/retrieves data from dbA.tableA AppB stores/retrieves data from dbB.tableA tableA definition is the same across these databases. To start with dbB.tableA was copied from dbA.tableA (assuming...
View ArticleWrite-lock a whole table during transaction
I need to perform a delicate operation to my table in which I will solely insert, delete and select upon all of my rows and no God may interfere with the table during this operation: the table will be...
View ArticleClik here to view.
Permanent count of waiting tasks (2) in Activity monitor
Now I'm observing in Activity Monitor permanent count of waiting tasks: and at "Resource waits" tab I see next: so, my question is: How to find and resolve this wait tasks? I suspect that it related...
View ArticleMySQL 5.7 replication of session variable "sql_mode" fails
MySQL documentation for v5.7 states about the replication of variables: In MySQL 5.7, the following session variables are written to the binary log and honored by the replication slave when parsing the...
View ArticleMongoDB HA by reading from Last Secondary not working
Our topology is (1 MongoDB server at each location) Primary Datacenter (main server, priority 10 ) DR datacenter (active standby, priority 5) On-Prem datacenter ( When shiz hits the fan, priority .5)...
View ArticleMySQL 5.6 replication causes 'waiting for table lock'
All of the sudden queries on slave server stopped with status "Waiting for table level lock" I restart mysql service and stop replications and locking does not show up anymore. Once I turn replications...
View ArticlePostgreSQL streaming replication lag for synchronous standbys
We use PostgreSQL 9.5 in a master + synchronous hot-standby setup, i.e., using synchronous_commit = on and using synchronous_standby_names='*'. Consequently, the standby has sync_state = sync in the...
View ArticleMySQL replication with multiple locations
We have developed centralized Point of Sales(POS)-(codeigniter/MySQL) system for 8 shops. All files and database in online server and shops can access POS system online. management can see real time...
View ArticleWhy do cross-database statements break replication when using filters?
For example, say you you have table A and table B on the master and on the slave you've set up replicate-do-db = A. Now if I do something like this: USE B; DROP TABLE A.sometable; Why should this not...
View ArticleRestoring MariaDB Galera cluster fails (IST/SST)
A few days ago we experienced a crash with one of our MariaDB Galera nodes. I'm having serious problems with syncing the offline node with it's master again. For now, the 2 nodes are running...
View ArticleFinding Row and Column filters in transactional replication
SQL Server Transactional Replication: I understand that T-Rep supports both row and column filters and this can be done through the GUI while setting up replication. I am trying to create SQL code...
View ArticleView-Specific MySQL Replication
I'm trying to replicate only a portion of a table on Computer A (running an instance of MySQL) to a MySQL instance on Computer B, something that could easily be represented by a view. I know it is not...
View Articlemysql replication status using a select query
Is it possible to get replication status from any system database table. using which i can identify whether the replication is up or down. I need to to know whether the SLAVE_IO_RUNNING and...
View ArticleLaggy slave OK to have only one system user in processlist?
In all the examples of a processlist on a mysql slave I've seen, there are two system users. I have a slave that is very far behind the master. When I do show a processlist, there is only one system...
View ArticleHow to measure or estimate the streaming replication lag in Postgres 9.2
I've been asked to reverse engineer an app that uses postgresql in the back end. I can see that there is some database replica tion going on... based on my reading, I *think it's called streaming...
View ArticleSQL Server 2014 Replication - The process could not connect to Subscriber 'xxx'
I have just set up very basic transactional replication on SQL Server 2014. The Publisher and Distributor are one and the same. I have configured the Publisher to push to the Subscriber, so any and all...
View ArticleNew Master-Master replication has stopped working
We're building a new MySQL server pair for high availability, and of course it's not like managing a single server. We're working with Ubuntu 14.04 LTS and MySQL 5.5.43 I had master-master replication...
View ArticleRedis master and slave use different memory
I deployed a redis replica set which consist of one master and one slave. From top command output, I figure out each memory usage. master: 8176352Byte * 8.5% = 678MB slave: 2050116Byte * 75.6% = 1513MB...
View ArticleReplicate SQL Server database (PUBLISHER) to Always ON Availability Groups...
https://msdn.microsoft.com/en-us/library/hh710046.aspx I have configured replication between Always ON Availability Groups (Listener) (PUBLISHER), remote distributor to XYZ SUBSCRIBER...with above link...
View ArticlePostgresql: replica and HA
I've postgresql 9.4. I'm aware that there are many answer on DBA and SO, I'm aware of the wiki and the documentation. But anyway, I can't understand in a simple way what's the right way to have a...
View Article