August 20, 2014

Percona Testing: Innodb crash / recovery tests available

Not everyone may know this, but there are precious few innodb crash recovery tests available. Some folks have noticed this and asked for something to be done about it, but unfortunately, no tests have been created for the main MySQL branch. The MySQL at Facebook branch has a number of tests that are quite interesting.  […]

MySQL Limitations Part 1: Single-Threaded Replication

I recently mentioned a few of the big “non-starter” limitations Postgres has overcome for specific use cases. I decided to write a series of blog posts on MySQL’s unsolved severe limitations. I mean limitations that really hobble it for major, important needs — not in areas where it isn’t used, but in areas where it […]

Missleading Innodb message on recovery

As I wrote about 2 years ago the feature of Innodb to store copy of master’s position in Slave’s Innodb tablespace got broken. There is a lot of discussions at the corresponding bug report while outcome of the fix remained uncertain for me (the bug is market duplicate while the bugs it seems to be […]

Recovery beyond data restore

Quite frequently I see customers looking at MySQL recovery as on ability to restore data from backup which can be far from being enough to restore the whole system to operating state, especially for complex systems. Instead of looking just at data restore process you better look at the whole process which is required to […]

MySQL Replication vs DRBD Battles

Well these days we see a lot of post for and against (more, more) using of MySQL and DRBD as a high availability practice. I personally think DRBD has its place but there are far more cases when other techniques would work much better for variety of reasons. First let me start with Florian’s comments […]

What is the longest part of Innodb Recovery Process ?

In MySQL 4.1 and above the longest part of recovery after crash for Innodb tables could be UNDO stage – it was happening in foreground and was basically unbound – if you have large enough transaction which needed to be undone this could take long hours. REDO stage on other hand always could be regulated […]

Innodb Recovery – Is large buffer pool always better ?

How does Buffer Pool size affects Innodb Performance ? I always expected the effect to be positive, Innodb with large buffer pool to performing better. Including Recovery of course. I even blogged about it. It turns out it is not always the case. Last week I was called to help with Innodb crash recovery on […]

Magic Innodb Recovery self healing

We have certain type of the table corrupting with Innodb, as it is limited to only one particular index on one particular table type it is likely to be Innodb bug but Heikki currently could not find what could be causing it. Happily as we have data stored in many tables of same format rather […]

What to tune in MySQL Server after installation

My favorite question during Interview for people to work as MySQL DBAs or be involved with MySQL Performance in some way is to ask them what should be tuned in MySQL Server straight after installation, assuming it was installed with default settings. I’m surprised how many people fail to provide any reasonable answer to this […]

MySQL Crash Recovery

MySQL is known for its stability but as any other application it has bugs so it may crash sometime. Also operation system may be flawed, hardware has problems or simply power can go down which all mean similar things – MySQL Shutdown is unexpected and there could be various inconsistences. And this is not only […]