Azure on availability group listener
Can someone explain briefly the role that an internal load balancer has in conjunction with the listener? I thought the listener was a way to abstract the calling method to the DB so that the client...
View ArticleUnable to start mongod server with default oplog size while trying replication
I was unable to create replication, i.e. rs.initiate() when oplog was having default value. My server had 400+ GB of space available. In MongoDB's official documentation default range for MMAP is 5% of...
View Articlemysql replication missed quite a lot SQL statement
I have set up a master/slave with mysql-5.1.73 The master's binlog format is "statement". The master and slave seemed running very well with slave status: Slave_IO_Running: Yes Slave_SQL_Running: Yes...
View ArticleMongoDB can't add new replica set member [rsSync] SEVERE: Got signal: 6
I have a replica set and I added a new member to the set. The initialSync begins for the new member and rs.status (on primary) shows STARTUP2 as status. However, after a long enough time, there's a...
View Articlenode-mongodb(replica set) memory issue ( error : no primary found in...
Problem: Twice or thrice a day our node-js process memory goes high and restarted or errored. ( normally it's fine with read & write operation ). I'm getting the following errors when this...
View Articleproblems of multi threaded slave without gtid enabled
We are in process of mysql up gradation and planning to configure multi threaded slave with 4 worker threads. We won't be able to enable GTID till all slaves and master are upgraded. So is it safe to...
View ArticlePromote a member to Primary in a ReplicaSet with Arbiter
I have the following replicaSet: "members" : [ { "_id" : 1, "host" : m1.host "arbiterOnly" : true }, { "_id" : 2, "host" : m2.host }, { "_id" : 3, "host" : m3.host } I am trying to force m2.host get...
View ArticleCan a slave with a dynamic ip update the master
How can I setup mySQL replication in such a way that a slave on localhost with dynamic IP can update the master as well as get updates from the master which has a static IP. The slave will not be...
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...
View ArticleHow to Upgrade Master Slave MySQL on AWS RDS?
I already have Master Slave configuration on AWS RDS. We want to upgrade 5.5 to 5.6.23. ..What should be correct sequence to Upgrade ? Upgrade Master ( Using Modify Instance ) --> Upgrade Slave...
View ArticleMySQL Circular Replication
I have this scenario where I have 4 MySQL servers (A,B,C,D), as this: Server (A) is always online, and serves as the main website. Servers (B,C and D) are online on random periods of the day, and not...
View ArticleCannot drop distribution database in SQL Server 2012
I am trying to drop distribution database but cannot as I am getting this error: The operating system returned error 21(The device is not ready.) to SQL Server during a read at offset 0x00000000056000...
View ArticleMySQL Error wth Relay logs - Could not open relay logs file for logging
We are receiving the following error. 2016-03-08 15:32:09 1184 [ERROR] MYSQL_BIN_LOG::move_crash_safe_index_file_to_index_file failed to move crash_safe_index_file to index file. 2016-03-08 15:32:09...
View ArticleSQL Server 2008 replication
We use SQL Server 2008 Express to customers sites. We need to maintain a backup to our portal. We first take a full backup from each customer site and then restore it to our portal. Then, on a regular...
View ArticleHow to achieve Master-Master replication in Postgres
I have a application that performs read and write on a Postgres DB. Now, for fault tolerance, I am planning to have a failover mechanism by placing a second database in a different region. Best...
View ArticleReplicating a data.frame according to a vector of lengths`
I have a data.frame: set.seed(1) short.df <- data.frame(id=letters[1:10],name=LETTERS[1:10]) And I want to replicate each row by a number of times given by a vector whose length equals...
View ArticleINSERT ... ON DUPLICATE KEY UPDATE with WHERE?
I'm doing a INSERT ... ON DUPLICATE KEY UPDATE but I need the update part to be conditional, only doing the update if some extra condition has changed. However, WHERE is not allowed on this UPDATE. Is...
View ArticleMongo replicated shard member not able to recover, stuck in STARTUP2 mode
I have following setup for a sharded replica set in Amazon VPC: mongo1: 8G RAM Duo core (Primary) mongo2: 8G RAM Duo core (Secondary) mongo3: 4G RAM (Arbiter) Mongo1 is the primary member in the...
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...
View ArticleRDS Replication Error (Apply Error 1406 / Truncation)
I have a MySQL RDS instance as a master, created a Read Replica from it, and ran some schema change operations on it. To be specific, I changed the charset and collation of all the tables and columns...
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