…, is now available. You can watch the recording and get the slides here. I got a lot of questions, and did not have enough time… cause blocking that would defeat the purpose of the tool. Q: When you say bail out, what does that mean? Does the tool clean up (i.e., remove table / triggers?) About cleanup.. What…
Post: Testing Virident FlashMAX 1400
May 4, 2012 By 3 Comments
… DL380 G6. Second note is, that I use a mode “turbo=1″ for Virident card. What does that mean? Apparently PCIe specification has… it is 1450 MiB/sec. This is best read throughput I’ve seen so far in my benchmarks. To see distribution of response time, the results for random read synchronous IO. There we can see that 1450 MiB/sec is not quite achievable…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
… buffer size of 256K, MariaDB 5.5 shows that Handler_mrr_rowid_refills = 1, which means the buffer is small…6, the optimizer chooses the wrong query execution plan. Let’s take a look at what are the good and…, and the query time for MySQL 5.6 and MariaDB 5.5 jumps to ~11min (this is the query time for…
Post: Announcement of Percona XtraDB Cluster 5.5.20 GA release
April 3, 2012 By 10 Comments
… the availability of the GA release of our new product Percona XtraDB Cluster. Percona XtraDB Cluster is… explain what Percona XtraDB Cluster is and how does it work, you still have time to…Percona XtraDB Cluster is fully compatible with MySQL or Percona Server in the following meaning: Data …
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 2 Comments
… more tables. What this means is that, select rows from first table participating in the joins are read, and then for each of these rows… 6M, the query time dropped to ~40s. So the maximum possible benefit is when size of both the buffers is increased appropriately. Also in the chart above the bottom…
Post: Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact
March 12, 2012 By 12 Comments
I have been working with Peter in preparation for the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5… Now let’s take a look briefly at what this enhancement actually is, and what is it aimed at. Index Condition Pushdown Traditional B… as range scans, where index parts after the part on which range condition is applied cannot be used for filtering records. For…
Comment: Joining many tables in MySQL - optimizer_search_depth
April 23, 2012 By 6 Comments
… which means “choose automatically”, which in turn means “choose depth 7″. Is this what your blog boils down to? At the time when I implemented the …determine what is a reasonable limit for the search depth (and the total number of tables) that can be optimized in reasonable time. I reached the …
Post: How FLUSH TABLES WITH READ LOCK works with Innodb Tables
March 23, 2012 By 20 Comments
…because of the time it may take to complete this statement. Lets look at what the problem is. As of MySQL…. What is worse as the statement started execution all writes will be blocked to the server, which in the …rows in set (0.00 sec) As result this means single run away select can effectively cause…
Comment: How FLUSH TABLES WITH READ LOCK works with Innodb Tables
March 24, 2012 By 20 Comments
Kristian, What do you mean by “snapshot what is recoverable”. Even without Flush tables with read lock, LVM snapshot should be recoverable 100% of the time. You might have found recovery bug but there have been very few of them. Typically problems with…
Post: Percona Toolkit 2.1 with New Online Schema Change Tool
April 5, 2012 By 9 Comments
… in the dead of the night on Sunday, and required overtime and time off, you know what I mean. A schema migration is an instant blocker in the critical path of…
