… affects both response time and throughput – The transaction log. The InnoDB transaction log handles REDO logging, this is the mechanism that provides the A… part of the DO-UNDO-REDO protocol InnoDB also records UNDO information, however that is stored outside of the transaction log and as such…
Post: Choosing proper innodb_log_file_size
July 3, 2006 By 12 Comments
… proportional to size of log files, so expect 1GB logs to take twice time to apply compared to 512MB logs. Redo phase is however only one of the phases of recovery. The other important one is undo phase – after log file… “redo” phase “undo” phase can’t be reduced by sizing your log files. Even more undo phase can be slower with small log files. Undo phase…
Comment: How InnoDB handles REDO logging
April 20, 2011 By 19 Comments
… undo and redo log in innodb. In InnoDB UNDO logging is handled via the UNDO log (Also referred to as the ROLLBACK segment). UNDO logging being the inverse of REDO…. >one possibility is don’t flush dirty pages until related redo-logs are flushed, but it looks only >allowing one transaction per…
Comment: How InnoDB handles REDO logging
February 3, 2011 By 19 Comments
… undo and redo log in innodb. In InnoDB UNDO logging is handled via the UNDO log (Also referred to as the ROLLBACK segment). UNDO logging being the inverse of REDO…. >one possibility is don’t flush dirty pages until related redo-logs are flushed, but it looks only >allowing one transaction per…
Comment: How InnoDB handles REDO logging
April 11, 2011 By 19 Comments
… the relationship between undo and redo log in innodb? How does innodb keep the consistent in the case of innodb_flush_log_at_trx_commit != 1? In other words, some pages are flushed and others aren’t, and while redo log is missed. one possibility is don’t flush dirty pages until related redo-logs are flushed, but it…
Post: Recovery after DROP & CREATE
August 22, 2012 By 1 Comment
… is no suitable string to grep etc. Using information from UNDO segment SYS_TABLES and SYS_INDEXES are normal InnoDB tables…. But the changes a transaction does are written to the redo log right before a successful response to COMMIT(or in a…_at_commit != 1). In that case we can scan the redo log: # ./s_tables /var/lib/mysql/ib_logfile1 sakila/actor sakila…
Post: How to estimate time it takes Innodb to Recover ?
May 9, 2007 By 7 Comments
… can overwrite matching log records in the log file (which is circular). Size of log records While we speak about log file size it… sequential order. Besides log replay phase there is also phase of flushing dirty buffers to the disk and undo phase – rolling back… increase recovery time even more I hope Heikki will enable redo and undo phases to be performed in the parallel, which should…
Comment: How InnoDB handles REDO logging
March 30, 2011 By 19 Comments
… both the page and the REDO log carry the LSN we know how where we are in the REDO log in terms of what… InnoDB goes into recovery mode is when it uses the REDO log (And UNDO) to update the on disk pages to represent the…
Comment: How InnoDB handles REDO logging
February 3, 2011 By 19 Comments
… both the page and the REDO log carry the LSN we know how where we are in the REDO log in terms of what… InnoDB goes into recovery mode is when it uses the REDO log (And UNDO) to update the on disk pages to represent the…
Post: Recovery deleted ibdata1
August 10, 2012 By 9 Comments
… a customer deleted the InnoDB main table space – ibdata1 – and redo logs – ib_logfile*. MySQL keeps InnoDB files open all the time… checkpoint age is zero, all pages are flushed: — LOG — Log sequence number 363096003 Log flushed up to 363096003 Last checkpoint at 363096003 Max… 16644 Purge done for trx’s n:o < 0 16644 undo n:o < 0 0 But if the last transaction wasn…
