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Displaying posts with tag: Replication (reset)
FOSDEM 2020

My post-FOSDEM detox has started - despite preparing by reading some survival guides, I hadn't really fathomed the variety and quantity (and quality) of beer that would flow over four days.  On reflection however, the beer flow has been far exceeded by the flow of tech content and conversation.

On Thursday and Friday I attended the pre-FOSDEM MySQL Days fringe event, where there were two tracks of talks and tutorials on MySQL including sessions on :
 - MySQL Server simplification
 - MySQL replication tooling improvements
 - Configuring group replication
 - Troubleshooting group replication
 - Using DNS for loadbalancing and failover
 - Upgrading to MySQL 8.0 …

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A Legacy Behavior of MySQL Corrupting Restored Backups (replicate-same-server-id = OFF)

In my previous post (Puzzled by MySQL Replication), I describe a weird, but completely documented, behavior of replication that had me scratching my head for hours because it was causing data corruption.  I did not give too many details then as I also wanted allowing you to scratch your head if you wished.  In this post, I describe this behavior in more details.

But first I need to apologize to

Fun with Bugs #92 - On MySQL Bug Reports I am Subscribed to, Part XXVI

I'd like to continue reviewing MySQL bug reports from Community users that I considered interesting and subscribed to. Unlike in the previous post in this series, I am not going to check test cases on any competitor product, but will use only recently released MySQL 5.7.29 and 8.0.19 for checks, if any. This time I'll concentrate on bugs reported in November 2019.

As usual, I mostly care about optimizer, InnoDB and replication related bugs. Here is the list:

  • Bug #97476 - "Range optimizer skips rows". This bug reported by
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Restrict MySQL replication to row based events

In a follow-up to the work presented on MySQL 8.0.18  where we introduced privilege checks for slave applier threads, in this post we present a new feature to further increase your ability to securely replicate your data: you can now restrict replication streams to row based events only.…

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MySQL 8.0.19 Replication Enhancements

Here comes another MySQL release, and together with it, a set of new replication features. As usual, we would like to summarize them. And, also as usual, follow up blogs will provide further details.

  • Configure Replication Applier to Require Row-based Replication only.

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Puzzled by MySQL Replication (War Story)

Recently, I was puzzled by MySQL replication !  Some weird, but completely documented, behavior of replication had me scratching my head for hours.  I am sharing this war story so you can avoid losing time like me (and also maybe avoid corrupting your data when restoring a backup).  The exact justification will come in a follow-up post, so you can also scratch your head trying to understand what

Debezium MySQL Snapshot From Read Replica And Resume From Master

In my previous post, I have shown you how to take the snapshot from Read Replica with GTID for Debezium MySQL connector. GTID concept is awesome, but still many of us using the replication without GTID. For these cases, we can take a snapshot from Read replica and then manually push the Master binlog information to the offsets topic. Injecting manual entry for offsets topic is already documented in Debezium. I’m just guiding you the way to take snapshot from Read replica without GTID.

Requirements:

  • Setup master slave replication.
  • The slave must have log-slave-updates=ON else connector will fail to read from beginning onwards.
  • Debezium connector should be able to …
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preFOSDEM 2020 MySQL Days: the schedule

The schedule of the preFOSDEM Day is now available !

We had a lot of proposals to deal with. Also this is a MySQL event where we, the MySQL Team has the possibility to show to you, our Community, all what we have working on to improve MySQL but also new stuff. We also invite some of our friends from the MySQL Community to talk about their experience.

I think we did a good selection and propose you new content. We are extremely happy to have Saverio Miroddi from TicketSolve talking about MySQL 8.0, Uber talking about InnoDB Cluster, and Facebook about Binlog.

As you can see, we will have 2 rooms, where one will be dedicated mostly to SQL and Optimizer topics but also tutorials.

You can also see that this year we also want to put some spot lights to MySQL NDB Cluster. You will see what is it, how is it used and what’s new. We will also have 2 community speakers sharing their MySQL NDB knowledge: Giuseppe Maxia, …

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MySQL GTID: restore a master from a replica’s backup

To avoid infinite replication loops MySQL doesn’t allow you to have log_slave_updates and replicate-same-server-id.

When using GTIDs that may lead to something not expected that you may not be aware of.

In this scenario, we have 2 MySQL servers using GTID. The sever uuid part of the GTID has been modified in the illustration to make it more clear. Both servers have log_slave_updates enabled too:

So far nothing unusual. So let’s write data on the master (MySQL A):

We can see that this first …

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Quick hack for GTID_OWN lack

One of the benefits of MySQL GTIDs is that each server remembers all GTID entries ever executed. Normally these would be ranges, e.g. 0041e600-f1be-11e9-9759-a0369f9435dc:1-3772242 or multi-ranges, e.g. 24a83cd3-e30c-11e9-b43d-121b89fcdde6:1-103775793, 2efbcca6-7ee1-11e8-b2d2-0270c2ed2e5a:1-356487160, 46346470-6561-11e9-9ab7-12aaa4484802:1-26301153, 757fdf0d-740e-11e8-b3f2-0a474bcf1734:1-192371670, d2f5e585-62f5-11e9-82a5-a0369f0ed504:1-10047.

One of the common problems in asynchronous replication is the issue of consistent reads. I've just written to the master. Is the data available on a replica yet? We have iterated on this, from reading on master, to heuristically finding up-to-date replicas based on heartbeats (see presentation and …

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