Showing entries 1 to 10 of 304
10 Older Entries »
Displaying posts with tag: cluster (reset)
How can I tell which Tungsten Connector mode I am using: Bridge, Proxy/Direct or Proxy/SmartScale?

Overview The Skinny

Part of the power of Tungsten Clustering for MySQL / MariaDB is its intelligent MySQL Proxy, known as the Tungsten Connector. Tungsten Connector has three main modes, and depending on the type of operations you are performing (such as if you need read-write splitting), we help you choose which mode is best.

The Question Recently, a customer asked us:

How can I tell which Tungsten Connector mode I am using: Bridge, Proxy/Direct or Proxy/SmartScale?

The Answer Connect and Observe

You may login through the Connector to tell the difference between Bridge mode and Proxy mode (either Direct or SmartScale):

In Proxy mode, you will see the -tungsten tag appended to the Server version string:

[Read more]
MySQL InnoDB Cluster – Recovering and provisioning with MySQL Enterprise Backup

Like I stated in my previous article - MySQL InnoDB Cluster - Recovering and provisioning with mysqldump : "As the administrator of a cluster, among others tasks, you should be able to restore failed nodes and to add (or remove) new nodes". Well, I still agree with myself :) MySQL customers using a Commercial Edition have access to MySQL Enterprise Backup (MEB) which provide enterprise-grade physical backup and recovery for MySQL. MEB delivers hot, online, non-blocking backups on multiple platforms including Linux, Windows, Mac & Solaris.

Where are the logs for a Tungsten Cluster?

The Question Recently, a customer asked us:

Where are the logs for a Tungsten Cluster and which are the proper log files to monitor if I do a master role switch to another node?

The Answer: Part I Both basic and advanced logs are available!

The basic logs are symbolic links into the log subdirectory for each layer of the cluster.

For example, this is the listing of the default log directory, /opt/continuent/service_logs:

connector-user.log -> /opt/continuent/tungsten/tungsten-connector/log/connector-user.log
manager-user.log -> /opt/continuent/tungsten/tungsten-manager/log/manager-user.log
mysqldump.log -> /opt/continuent/tungsten/tungsten-replicator/log/mysqldump.log
replicator-user.log -> /opt/continuent/tungsten/tungsten-replicator/log/replicator-user.log
xtrabackup.log -> /opt/continuent/tungsten/tungsten-replicator/log/xtrabackup.log

As you can see, each log file is a …

[Read more]
MySQL InnoDB Cluster – Recovering and provisioning with mysqldump

As the administrator of a cluster, among other tasks, you should be able to restore failed nodes and grow (or shrink) your cluster by adding (or removing) new nodes. In MySQL, as a backup tool (and if your amount of data is not too big), you can use mysqldump a client utility that performs logical backups. The results are SQL statements that reproduce the original schema objects and data. For substantial amounts of data however, a physical backup solution such as MySQL Enterprise Backup is faster, particularly for the restore operation. But this is the topic of my next blog post :)

The Fast Way to Import CSV Data Into a Tungsten Cluster

The Question Recently, a customer asked us:

After importing a new section of user data into our Tungsten cluster, we are seeing perpetually rising replication lag. We are sitting at 8.5hrs estimated convergence time after importing around 50 million rows and this lag is climbing continuously. We are currently migrating some of our users from a NoSQL database into our Tungsten cluster. We have a procedure to write out a bunch of CSV files after translating our old data into columns and then we recursively send them to the write master using the mysql client. Specifically our import SQL is doing LOAD DATA LOCAL INFILE and the reading in a large CSV file to do the import. We have 20k records per CSV file and we have 12 workers which insert them in parallel.

Simple Overview The Skinny

In cases like this, the slaves are having trouble with the database unable to keep up with the apply stage …

[Read more]
Percona XtraDB Cluster 5.7.26-31.37 Is Now Available

Percona is glad to announce the release of Percona XtraDB Cluster 5.7.26-31.37 on June 26, 2019. Binaries are available from the downloads section or from our software repositories.

Percona XtraDB Cluster 5.7.26-31.37 is now the current release, based on the following:

All Percona software is open-source and free.

Bugs Fixed

[Read more]
What is the Best Way to Check the Health of a Tungsten Cluster Before a Switch?

The Question Recently, a customer asked us:

What would cause a node switch to fail in a Tungsten Cluster?

For example, we saw the following during a recent session where a switch failed:

cctrl> switch to db3 

SELECTED SLAVE: db3@alpha 
SET POLICY: MAINTENANCE => MAINTENANCE 
PURGE REMAINING ACTIVE SESSIONS ON CURRENT MASTER 'db1@alpha' 
PURGED A TOTAL OF 0 ACTIVE SESSIONS ON MASTER 'db1@alpha' 
FLUSH TRANSACTIONS ON CURRENT MASTER 'db1@alpha' 
Exception encountered during SWITCH. 
Failed while setting the replicator 'db1' role to 'slave' 
ClusterManagerException: Exception while executing command 'replicatorStatus' on manager 'db1' 
Exception=Failed to execute '/alpha/db1/manager/ClusterManagementHelper/replicatorStatus alpha db3' 
Reason= 
CLUSTER_MEMBER(true) 
STATUS(FAIL) 
+----------------------------------------------------------------------------+ 
|alpha | …
[Read more]
Percona XtraDB Cluster 5.6.44-28.34 Is Now Available

Percona is glad to announce the release of Percona XtraDB Cluster 5.6.44-28.34 on June 19, 2019. Binaries are available from the downloads section or from our software repositories.

Percona XtraDB Cluster 5.6.44-28.34 is now the current release, based on the following:

All Percona software is open-source and free.

Bugs Fixed

[Read more]
Why is My Java Application Freezing Under Heavy I/O Load?

The Question Recently, a customer asked us:

Why would heavy disk IO cause the Tungsten Manager and not MySQL to be starved of resources?

For example, we saw the following in the Manager log file tmsvc.log:

2019/06/03 00:50:30 | Pinging the JVM took 29 seconds to respond.
2019/06/03 00:50:30 | Pinging the JVM took 25 seconds to respond.
2019/06/03 00:50:30 | Pinging the JVM took 21 seconds to respond.
2019/06/03 00:50:30 | Pinging the JVM took 16 seconds to respond.
2019/06/03 00:50:30 | Pinging the JVM took 12 seconds to respond.
2019/06/03 00:50:30 | Pinging the JVM took 8 seconds to respond.

The Answer Why a Java application might be slow or freezing

The answer is that if a filesystem is busy being written to by another process, the background I/O will cause the Java JVM garbage collection (GC) to pause.

This problem is not specific to Continuent Tungsten …

[Read more]
Perform Complex Online Schema Changes on MySQL / MariaDB / Percona Server Leveraging Tungsten Clustering

Background The Skinny

Performing schema changes often requires extended downtime for applications. This is due to MySQL needing to rebuild tables for common schema change operations. Tools like pt-online-schema-change have been written to try to overcome the downtime associated with schema changes, however they are complex and put a high load on the database. Amazon’s Aurora improves some schema changes operations, but still requires a table rebuild for common operations like adding a column using before or after, or simply to add a column with a default value. Rebuilding a table with millions of rows can take hours and prevent writes to that table the entire time.

How Can Tungsten Clustering Keep Applications Running? How Does It All Work?

[Read more]
Showing entries 1 to 10 of 304
10 Older Entries »