…MySQL takes much more memory than you would expect, causing swapping or other problems. This simple problem on the surface becomes challenge with MySQL…memory usage shrinks can be very helpful in diagnostics. If you have many applications it might make…
Post: Joining many tables in MySQL - optimizer_search_depth
April 20, 2012 By 6 Comments
…than 1000 rows and doing it completely in memory. The plan optimizer picked was very good one,…a bit better performance but I decided against using this as I did not want to …more than 7 at which complexity is reasonable. This makes Timour explanation somewhat conflicting though as if we assume MySQL…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
…’t really make any positive difference to the query times for MySQL 5.6, when the workload fits entirely in memory, because there… is used. Another interesting thing to note is that MySQL 5.6 and MariaDB 5.5 are both reading more rows than MySQL 5…_key is more or less the same for MariaDB 5.5 when compared to MySQL 5.5, and this does not make sense…
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 2 Comments
… these optimizations. Batched Key Access Traditionally, MySQL always uses Nested Loop Join to join two or more tables. What this means is that… the first operand used in the build step is such that the hash table fits in memory. You can read more about the… Scan making much of a difference here. Now let’s take a look at the status counters. Counter Name MySQL 5.5 MySQL…
Post: Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact
March 12, 2012 By 12 Comments
… in preparation for the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. We are taking a… optimizer enhancement Index Condition Pushdown (ICP). Its available in both MySQL 5.6 and MariaDB 5.5 Now let’s take… the part on which range condition is applied cannot be used for filtering records. For example, suppose you have a key…
Post: Should we give a MySQL Query Cache a second chance ?
April 10, 2011 By 63 Comments
…MySQL Query Cache so it once again is appealing to improve performance for MySQL Applications ? Make it Lockless Can we re-implement MySQL…when simply use it. More Granular Invalidation…used from query syntax may be hard. Query Cache Storage Engines MySQL Query Cache now stores queries in local memory…
Post: Why Swapping is bad for MySQL Performance ?
January 18, 2010 By 11 Comments
So you get MySQL or other applications using too much memory on the box or OS behaving funny and using more memory for cache and pushing… of IOs or make them more sequential. Most of these were designed before SSD era. For example Insert Buffer in MySQL makes a special effort to avoid (delay) IO. If it happens to go to swap file it will more than…
Post: Should I buy a Fast SSD or more memory?
April 8, 2010 By 10 Comments
…for MySQL, it’s interesting to see what room we now have to scale up – cheap memory, fast …a customer/week using Fusion-IO cards. One interesting choice I’ve seen people make however, is…get the same improvement with memory, you would have needed to add 60% more memory -or- 260% more memory for a 5x…
Post: The #1 mistake hosting providers make for MySQL servers
July 25, 2008 By 30 Comments
… you want to use more memory — and they will gladly install 8 or 16GB of memory for you, but MySQL can’t use it because it runs in a single process, which is limited to about 2.5GB of memory. And…, set it up as a slave, switch your site to use it, and then rebuild the old server. That 32-bit…
Post: MySQL-Memcached or NOSQL Tokyo Tyrant - part 1
October 15, 2009 By 16 Comments
…. Now bumping this up to 2GB actually makes the TPS jump around a lot, sometimes …have seen many clients do. Using this application I can then compare using MySQL to using MySQL + Memcached, and then …they need to scale more, we need more memory! If performance sucks, we must need more. So here comes …
