…. I’ve updated column to have bunch of long random strings update sbtest set c=concat(sha1(… large enough to fit complete table with index (but is a bit too small to keep 2 copies) …. Take Away: If you’re having large tables and need to run ALTER TABLE which rebuilds the table or OPTIMIZE TABLE do …
Post: On Character Sets and Disappearing Tables
June 21, 2012 By 1 Comment
…; trying to do something like “ALTER TABLE bar DROP j” or “ALTER TABLE bar MODIFY COLUMN j… what we’d hope would happen, too, lest table “foo” suddenly end up …But suppose that this was actually a long-running ALTER statement. Maybe we got pre-… into a new table, but you’ll need to go take a look …
Comment: Upgrading MySQL
January 17, 2010 By 24 Comments
… database is sufficiently large, as this takes too long. In that case often the alternative is to take a copy of a running slave… 5.0…. If the table is large you are back to the problem that the dump/load takes ages. Then again none of this is really necessary: ALTER TABLE ENGINE=INNODB rebuilds the table under 5.1…
Post: MySQL EXPLAIN limits and errors.
July 24, 2006 By 6 Comments
… different. Also there is no way to tell you how ALTER table would be executed – will in add index live as it… at too many table join combinations in joins with very large tables is elevated, however there are still cases when it may take too long. Most practically important one is if Derived tables (selects…
Post: My Innodb Feature wishes
May 4, 2006 By 30 Comments
… is especially bad for rollback of failed inserts which may take too long to complete Index build by sort. This is in ToDo… be much faster as well as ALTER TABLE (expecially together with ability to create index without table rebuilding) Buffer pool improvements. I would… real one to unique. Tablespaces. To call “innodb_file_per_table” option tablespaces is a joke. It is better than nothing…
Post: Percona Toolkit Webinar followup Q&A
December 19, 2012 By 1 Comment
…renaming the table take a long time, and what about the transaction in the meanwhile? The rename table itself …, it may be faster to run the alter table command directly (specially so when dropping an index…speed, or other factors make cloning a server too difficult, and just clone the host otherwise….
Post: Working with large data sets in MySQL
July 5, 2007 By 12 Comments
… because things are going to take a lot of time. Think about 500GB table for example – ALTER TABLE make take days or even weeks depending on your storage engine and set of indexes, Batch Jobs can take… can’t simply run ALTER TABLE because table will stay locked for too long you would need to do careful process of ALTERing table on the slave…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…, too…. Com_admin_commands | 255868807 | 11893 | | Com_alter_db | 0 …tables, I’ll paste in mysql> show global variables like ‘%table_size%’; +———————+———–+ | Variable_name | Value | +———————+———–+ | max_heap_table_size | 268435456 | | tmp_table…take a long time…
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
… huge MyISAM tables and taking downtime, I would not use MyISAM for anything but read-only tables when things…doesn’t save you from the downtime caused by ALTER TABLE — a typical reason to think about master-master …’re okay with long queries that read a lot of rows — MySQL can’t handle too many of …
Post: Estimating Replication Capacity
July 20, 2010 By 4 Comments
… “hot” replication capacity as well as how long replication warmup takes. It is very typical for servers … time it takes to warmup too (there are different things you can do about it too). First … to normal operational load – if you push heavy ALTER TABLE through replication they will surely get your …
