Search Results for: disk sort

Finding what Created_tmp_disk_tables with log_slow_filter

Whilst working with a client recently I noticed a large number of temporary tables being created on disk.

How Innodb flushes data to the disk ?

In my previous post I was a bit wrong giving Innodb some properties it does not have. In fact Innodb does not currently sort pages in their position order flushing them to disk. Pages to be flushed are instead identified by other means – LRU and pages which contain oldest LSN (so which were flushed […]

New PERFORMANCE_SCHEMA defaults in MySQL 5.7.7

I thought it was worth a moment to reiterate on the new Performance Schema related defaults that MySQL 5.7.7 brings to the table, for various reasons. For one, most of you might have noticed that profiling was marked as deprecated in MySQL 5.6.7. So it is expected that you invest into learning more about Performance […]

MySQL 5.7 key features

The other day I was discussing new features of MySQL 5.7 with a Percona Support customer. After that conversation, I thought it would be a good idea to compile list of important features of MySQL 5.7. The latest MySQL 5.7.6 release candidate (RC) is out and is packed with nice features. Here’s a list of […]

MySQL indexing 101: a challenging single-table query

We discussed in an earlier post how to design indexes for many types of queries using a single table. Here is a real-world example of the challenges you will face when trying to optimize queries: two similar queries, but one is performing a full table scan while the other one is using the index we […]