I have been working with Peter in preparation for the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. We are taking a look at and benchmarking optimizer enhancements one by one. So in the same way this blog post is aimed at a new optimizer enhancement Index Condition …
Post: Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact
March 12, 2012 By 12 Comments
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
… primary key lookup. Thereby, converting Random access to one or more sequential access. There is one another interesting thing that has… calls made to the storage engine to perform the index record read and then to perform the MRR range scan on the… in the buffer. But there is no performance improvement when the workload is in-memory, in fact MRR adds extra sorting overhead…
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 2 Comments
… performed on table2. Of course this could mean a lot of random lookups in case the dataset does not fit into memory… will be performed. So key-ordered scan is basically an extension of MRR to secondary keys. You can read more about Key… step is such that the hash table fits in memory. You can read more about the hash join algorithm here. Now let…
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,…yet making it unusable to check the optimizer performance. Solution for this problem was to use set…I think faster execution plan computation would be more important than backward compatibility. In MySQL 5.6…
Post: Should I buy a Fast SSD or more memory?
April 8, 2010 By 10 Comments
… buffer pool of between 2G and 22G (to test performance compared to memory fit). Hardware was our Dell 900 (specs here). To… painful point for many customers – because while memory decreased by only ~10% the performance dropped by 2.6 times! In production… To get the same improvement with memory, you would have needed to add 60% more memory -or- 260% more memory for a 5x improvement.Â…
Post: Is there benefit from having more memory ?
November 19, 2010 By 10 Comments
…-or-more-memory/, caused quite interest, especially on topic SSD vs Memory. That time I used fairy small dataset, so it caused more questions… not used) This allows as to see effect of having more memory available. The graph result is: and raw numbers are on…) 7633.38 (ratio 2.99) So you see doubling memory gives 3x ! performance improvement. And it is despite we store data on…
Post: The two even more fundamental performance metrics
May 5, 2011 By 6 Comments
… concurrency. I derived all of these metrics from two “even more fundamental” performance metrics, which I’ll call the “basic” metrics. That… dispersion, an amazingly useful metric for discovering periods of poor performance), and more. Analyze the distribution of service times. Service time is… running a simple read-mostly workload with most data in memory. If we slice the arrivals and completions into buckets, a…
Post: Tokyo Tyrant - The Extras Part II : The Performance Wall
November 11, 2009 By 3 Comments
… more expensive disk based operations.   As fast as any application is, as you read off disk opposed to memory performance is going to drop off substantially. One of the more difficult things to test with Tyrant is disk bound performance… the buffer pool the faster the performance: Even here the performance drop-off once you exhaust memory is relative. The focus here…
Post: Why Swapping is bad for MySQL Performance ?
January 18, 2010 By 11 Comments
… or other applications using too much memory on the box or OS behaving funny and using more memory for cache and pushing application to the swap. This causes swapping and causes performance problems. This much… going to impact your performance more than just normal IO and here are 3 reasons why. If you know more please let me…
Post: When is it a time to upgrade memory ?
September 16, 2008 By 11 Comments
…=O_DIRECT) and see how performance depends on buffer size so you get and understanding what Memory-To-Disk ratio is optimal for your application, or at which point performance drops dramatically. It is…_pool_size you can use it as guidance to add more memory or more servers. Of course this is all oversimplifications – you’ve…
