June 19, 2013

Post: Implementing SchemaSpy in your MySQL environment

June 4, 2013 By 2 Comments

… is explicit.  This has an impact on how SchemaSpy identifies the relationship, and whether you … specific for MySQL, but note that SchemaSpy works for pretty much all the popular RDBMS out… columns/tables based on names, tables without indexes, columns flagged ‘nullable’ and ‘must be unique’ (woops…

Filed Under: Insight for DBAs, Insight for Developers, MySQL Tagged With: ,

Post: MySQL Query Patterns, Optimized - Webinar questions followup

June 3, 2013 By 2 Comments

…try writing a SQL query optimizer and see how easy it is?  ;-)  Generative grammars like SQL can… the primary key solution for random selection only work when the IDs for movies are distributed uniformly… each correlation name (k1, k2, k3) is an index lookup.  Look at the EXPLAIN output — it accesses…

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Comment: Sphinx search performance optimization: multi-threaded search

May 25, 2013 By 10 Comments

Thanks Aurimas, I misunderstood the nature of how the indexes would work. Thanks for posting this also, it was a great help to me. I really does speed up the searches.

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Post: Is Synchronous Replication right for your app?

May 14, 2013 By 18 Comments

… is a single row (well, the PRIMARY KEY index entry for that row).  This means typically on… (innodb_flush_log_at_trx_commit != 1), or work around it with by fsyncing to memory (Battery… SET count = count + 1 where achievement = ‘killed_troll’; How many players might accomplish this achievement at the…

Filed Under: MySQL, Percona Software, XtraDB Cluster Tagged With: , , , , , ,

Post: Galera Flow Control in Percona XtraDB Cluster for MySQL

May 2, 2013 By 5 Comments

…. This may sound counter-intuitive at first: how would synchronous replication get behind? As I’…_master_slave=YES; gcs.fc_factor=1.0″; Working with flow control What happens during flow …A small fc_limit does however keep the certification index smaller in memory. It keeps the certification interval…

Filed Under: Insight for DBAs, Percona Live, XtraDB Cluster Tagged With: , , ,

Post: Is your MySQL buffer pool warm? Make it sweat!

April 16, 2013 By 6 Comments

… for replication. The buffer pool and adaptive hash index on the standby server will not have recently … pool pages were loaded from disk. Replaying Queries Working with Groupon, we have developed a solution to… `tail -f slow.log`, except that it knows how to follow the log stream across log rotation …

Filed Under: Insight for DBAs, Insight for Developers, MySQL, Percona Software Tagged With: , , , , , , ,

Post: How to find wrong indexing with glance view

August 21, 2008 By 27 Comments

… understand how indexing works and so index all columns used in the queries…. separately. So you end up with table which has say 20 indexes… need to have multiple column indexes for optimal performance. But wait. Do not go ahead and index all combinations. This would likely…

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Post: How Percona does a MySQL Performance Audit

November 24, 2008 By 17 Comments

… work we do is often not simple at all. It’s impossible to predict. A customer may call and ask “how long…. You cannot consider any one of these factors (schema, queries, indexing) in isolation, because they are tightly bound together, and tweaking…. This is where you need to really know how to write queries and how EXPLAIN works. At Percona, we have peer training constantly…

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Post: Multi Column indexes vs Index Merge

September 19, 2009 By 31 Comments

… how indexes are created. Quite commonly people just index individual columns as they are referenced in where clause thinking this is the optimal indexing… index in this case. In case you’re using OR between columns – single column indexes are required for index merge to work and combined indexes…

Filed Under: Insight for DBAs, MySQL Tagged With:

Post: 3 ways MySQL uses indexes

September 12, 2009 By 28 Comments

… describes how MySQL uses single index – there are more complex rules of how indexes will be used if you look at multiple indexes usage with “index merge” Using Index to… you have both restriction and sorting things like this would work A=5 ORDER BY B ; A=5 ORDER BY B…

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