…with this partitioning, however since you’ll have to look in each of the ten partitions to query … seeing. The periodic performance variation corresponds to filling up a partition and starting a new one. (If … a 55GB buffer pool, we would expect the primary table to simply fit. But with all 4 indexes …
Post: How FLUSH TABLES WITH READ LOCK works with Innodb Tables
March 23, 2012 By 20 Comments
… FLUSH TABLES WITH READ LOCK can be quite large because of the time it may take to complete this statement. Lets look at what the problem is. As of MySQL 5.5 FLUSH TABLES WITH READ LOCK does not… similar option. This option can be especially helpful when backing up data from the slave with –safe-slave-backup option, as…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
… second blog post in the series of blog posts leading up to the talk comparing the optimizer enhancements in MySQL 5… take a look at what are the good and bad query execution plans. a. Bad Plan id select_type table type possible… when benchmarking ICP, the optimizer made a wrong choice. It looks like that there is still improvement and changes needed in…
Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5
April 4, 2012 By 2 Comments
… called the build step. After the hash table has been created, rows from table t2 are read and hash function is applied… the join condition and then a hash table lookup is performed, on the hash table we created earlier. This step is known… not warmed up, so that it does not have the relevant pages loaded up already. Now let’s take a look at the…
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 3 Comments
… – orphaned prepared statements, user variables, huge network buffer (can grow up to max_packet_size per connection) are all connection buffers… many tables application can create it does not really allows to restrict memory usage. For Permanent tables it is easy. We can look at information_schema to see how much memory is being used by current MEMORY tables…
Post: Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact
March 12, 2012 By 12 Comments
… 5.6 and MariaDB 5.5. We are taking a look at and benchmarking optimizer enhancements one by one. So in….6 and MariaDB 5.5 Now let’s take a look briefly at what this enhancement actually is, and what is…
Post: Introducing new type of benchmark
February 25, 2012 By 16 Comments
… times) When it is useful? At this moment I am looking to answer on questions like: – When we add additional node… the server. For example, the famous problem with DROP TABLE performance. Does DROP TABLE, running in separate session, affect a response time… response time grows linearly up to ~30 sec, where benchmark stops, because the queue is full. I am looking for your comments…
Comment: InnoDB vs MyISAM vs Falcon benchmarks - part 1
March 4, 2012 By 117 Comments
… looks like 1024+ threads may start causing problems. So a bit shortsighted of the person doing the benchmarks not to test up the number of threads that appear useful. At least people can then decide which table engine is best…
Post: MySQL-Memcached or NOSQL Tokyo Tyrant - part 1
October 15, 2009 By 16 Comments
… 2 Million and looks up the result via that key. It then uses data from that random row to look up a second….) Use the data from that row to lookup up a row in another table based on a text field ( called email address… 2 Million and looks up the result via that key. It then uses data from that random row to look up a second piece…
Post: Lost innodb tables, xfs and binary grep
November 9, 2010 By 11 Comments
… did have a backup set up, it’s just that some (most important) tables weren’t backed up. We did not try any… isn’t new, I kind of knew grep couldn’t look for binary “junk”, but I really needed it to. Why… had to look for was this sequence: 0007000300070008. I was expecting a lot of mismatches but in fact I ended up with…
