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Search Results for: mysql get number of rows in innodb

MySQL performance implications of InnoDB isolation modes

Over the past few months I’ve written a couple of posts about dangerous debt of InnoDB Transactional History and about the fact MVCC can be the cause of severe MySQL performance issues. In this post …


How well does your table fit in the InnoDB buffer pool in MySQL 5.6+?

Some time ago, Peter Zaitsev posted a blog titled “How well does your table fits in innodb buffer pool?” He used some special INFORMATION_SCHEMA tables developed for Percona Server 5.1 to report how much of …


InnoDB crash recovery speed in MySQL 5.6

It has been a while since I have looked at InnoDB crash recovery. A lot has change in the last few years – we have serious crash recovery performance improvements in MySQL 5.5 and MySQL …


InnoDB’s multi-versioning handling can be Achilles’ heel

I believe InnoDB storage engine architecture is great for a lot of online workloads, however, there are no silver bullets in technology and all design choices have their trade offs. In this blog post I’m …


Recover MySQL root password without restarting MySQL (no downtime!)

Disclaimer: Do this at your own risk! It doesn’t apply if you’re using Pluggable authentication and certainly won’t be usable if/when MySQL system tables are stored on InnoDB What is the situation? The situation is …


MySQL 5.6 Transportable Tablespaces best practices

In MySQL 5.6 Oracle introduced a Transportable Tablespace feature (copying tablespaces to another server) and Percona Server adopted it for partial backups which means you can now take individual database or table backups and your …


Avoiding MySQL ALTER table downtime

MySQL table alterations can interrupt production traffic causing bad customer experience or in worst cases, loss of revenue. Not all DBAs, developers, syadmins know MySQL well enough to avoid this pitfall. DBAs usually encounter these …


MySQL’s INNODB_METRICS table: How much is the overhead?

Starting with MySQL 5.6 there is an INNODB_METRICS table available in INFORMATION_SCHEMA which contains some additional information than provided in the SHOW GLOBAL STATUS output – yet might be more lightweight than PERFORMANCE_SCHEMA. Too bad …


How to deal with MySQL deadlocks

A deadlock in MySQL happens when two or more transactions mutually hold and request for locks, creating a cycle of dependencies. In a transaction system, deadlocks are a fact of life and not completely avoidable. …


Innodb transaction history often hides dangerous ‘debt’

In many write-intensive workloads Innodb/XtraDB storage engines you may see hidden and dangerous “debt” being accumulated – unpurged transaction “history” which if not kept in check over time will cause serve performance regression or will …