As promised, my slides from FOSDEM25 and Pre-FOSDEM MySQL Belgian Days :
And since I was asked several times about MySQL test case demonstrating glibc-malloc memory fragmentation / leaks -- here are all the details :
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I have been looking into “dolphie” lately, and have to say, “thanks Charles!”. I actually first saw dolphie via Lefred’s MySQL Belgian Days and installed it just after looking into the slidedeck. But never got around to looking further… until now.
We can use so many different observability (o11y?) tools to get notifications, alerts, react, generate reports, etc. from so many different companies, using agents, proxies, repositories, and so on and so forth. And after exchanging experiences with dolphie’s author himself, Charles, the idea here is to go that little bit further in …
[Read more]In MySQL 8.0 we introduced a totally new design for InnoDB REDO Log management. The main difference was about implementing a lock-free solution for user threads, and use dedicated REDO threads for all background IO write work.
for more details, see an excellent and very detailed article by Pawel : https://dev.mysql.com/blog-archive/mysql-8-0-new-lock-free-scalable-wal-design/
However, over a time we also added an option to let users to switch REDO threads=OFF to enforce REDO log processing efficiency in some particular cases. Unfortunately this feature created a lot of confusions for MySQL users, and many ones interpreted this in different ways, providing different and sometimes opposite advices, etc..
My main advice will be always : test each feature yourself and within your …
[Read more]Few weeks ago with a big curiosity I was reading several articles published by Percona about TPCC Benchmark results and MySQL 8.0 "checkpointing" issues..
Unfortunately, in these articles there was no any explanation nor any tentative to understand what is going on, an probably at least try and validate some "first coming in mind" tuning / troubleshooting options.. (And even no any try to show in action so often advertised PMM, and see on what it'll point ?)..
All in all, in the following article I'll try to feel up the "white holes" left in this TPCC testing..
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The Replicator is a critical piece of the Tungsten Clustering solution for MySQL / MariaDB, as well as its own stand-alone data replication product. Automatic recovery is a feature that enables the Replicator to go back online in the event of a transient failure. In this blog we discuss how to enable Automatic Recovery. For more information about Auto-Recovery, please click here to visit the online documentation page.
The Question Recently, a customer asked us:
We see that the replicators receive a transaction which has a deadlock error in it:
pendingError : Event application failed: seqno=82880882 fragno=0 message=java.sql.SQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction
If one performs a service online, it comes back online without issue and continues …
[Read more]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]
Please join Percona’s CEO, Peter Zaitsev as he presents MySQL: Scaling and High Availability – Production
Experience Over the Last Decade(s) on Tuesday, June 19th,
2018 at 7:00 AM PDT (UTC-7) / 10:00 AM EDT (UTC-4).
Percona is known as the MySQL performance experts. With over 4,000 customers, we’ve studied, mastered and executed many different ways of scaling applications. Percona can help ensure your application is highly available. Come learn from our playbook, and leave this …
[Read more]Changes as compared to Monyog MySQL Monitor v8.4.1 include:
This release fixes a few minor bugs only and implements a number of user requests.
Features:
Bug Fixes:
With Halloween all but a distant memory, the time has come to turn our attention to the upcoming holiday season. First, Thanksgiving, then Black Friday and Cyber Monday, culminating in the Christmas/boxing week shopping bonanza. For business owners, this time of the year marks the long-awaited year’s end profit taking. For some DBA’s, it brings fear, trepidation, and even sleepless nights toiling away to bring systems back online.
Thankfully, this need not be the case. With a little proactive tweaking of MySQL performance variables, you can insulate your database server(s) against the onslaught of increased demand that the shopping season brings.
Tip #1: Determine the Maximum Number of MySQL Connections
A good starting estimate for the maximum number connections on MySQL is one for every five requests to your web server. A few of those five requests to your web server will be for resources like CSS style sheets, …
[Read more]MySQL 5.7 introduced the LOGICAL_CLOCK type of multi-threaded slave (MTS). When using this type of parallel replication (and when slave_parallel_workers is greater than zero), slaves use information from the binary logs (written by the master) to run transactions in parallel. However, enabling parallel replication on slaves might not be enough to get a higher replication throughput (VividCortex