Search Results for: innodb log file recovery

Connecting orphaned .ibd files

There are two ways InnoDB can organize tablespaces. First is when all data, indexes and system buffers are stored in a single tablespace. This is typicaly one or several ibdata files. A well known innodb_file_per_table option brings the second one. Tables and system areas are split into different files. Usually system tablespace is located in […]

InnoDB Flushing: Theory and solutions

I mentioned problems with InnoDB flushing in a previous post. Before getting to ideas on a solution, let’s define some terms and take a look into theory. The two most important parameters for InnoDB performance are innodb_buffer_pool_size and innodb_log_file_size. InnoDB works with data in memory, and all changes to data are performed in memory. In […]

MySQL Limitations Part 2: The Binary Log

This is the second in a series on what’s seriously limiting MySQL in certain circumstances (links: part 1). In the first part, I wrote about single-threaded replication. Upstream from the replicas is the primary, which enables replication by writing a so-called “binary log” of events that modify data in the server. The binary log is […]

Why you can’t rely on a replica for disaster recovery

A couple of weeks ago one of my colleagues and I worked on a data corruption case that reminded me that sometimes people make unsafe assumptions without knowing it. This one involved SAN snapshotting that was unsafe. In a nutshell, the client used SAN block-level replication to maintain a standby/failover MySQL system, and there was […]

How innodb_open_files affects performance

Recently I looked at table_cache sizing which showed larger table cache does not always provides the best performance. So I decided to look at yet another similar variable – innodb_open_files which defines how many files Innodb will keep open while working in innodb_file_per_table mode. Unlike MyISAM Innodb does not have to keep open file descriptor […]

Copying InnoDB tables between servers

The feature I announced some time ago is now available in our latest releases of XtraBackup 0.8.1 and XtraDB-6. Now I am going to show how to use it (the video will be also available on Let’s take tpcc schema and running standard MySQL ® 5.0.83, and assume we want to copy order_line […]

Improving InnoDB recovery time

Speed of InnoDB recovery is known and quite annoying problem. It was discussed many times, see: This is problem when your InnoDB crashes, it may takes long time to start. Also it affects restoring from backup (both LVM and xtrabackup / innobackup) In this is simple test, I do crash mysql during in-memory […]