Percona's MySQL & InnoDB performance and scalability blog
…number of children, parents, count of columns, row counts, and comments — a great way for a high level overview of the table sizes and an easy way to…
…to the SELECT part of the query. convert.php This script takes as one argument the default database. Notice in…to calculate the number of lines in the order_lines table, three orders of magnitude more quickly than COUNT(*). mysql> select count…
…to 2010′; mysql> use ontime1; Database changed mysql> show table…of 1 to 20 nodes. cd shard-query #generate a config for 20 shards (adjust to your number of…query script will run one more more semicolon terminated SQL statements. The queries for the benchmark are in ~ec2-user/shard-query/queries.sql…
…numbers of queries which examine a lot of data. What is Shard-Query? Shard-Query was initially conceived as a utility to add parallelism to…database servers can add this parallelism natively, but most of those are not open source. In the future, Shard-Query can be extended to other database…
…count(col1) from table; If you know your SQL well, you know COUNT() has two meanings. 1) count the number of rows 2) count the number of…to count the number of distinct values, but you left out the DISTINCT keyword. That’s also a bug in your query. You meant to count the number of…
…of “new” InnoDB tablespace files in our database…table by querying the various I_S.INNODB_FT_* tables. In particular, the INNODB_FT_CONFIG table is supposed to…of the other I_S tables, I do find that the number of rows in I_S.innodb_ft_index_table…
…to show how to count the number of unique words, an how many times those words appear in a document. Set based processing of…query. If your database system can not provide native parallelism, then performance will be poor. — SQL TO SEND TO…
…tables in use 1, locked 0 MySQL thread id 8079, query id 728899 localhost root Sending data select sql…number of tables used by transaction in question (meaning it was accessed) and number of tables locked by transactions. Innodb does not lock tables for normal operation so number of tables…
…table). In order to demonstrate the power of Shard-Query it is important to test complex queries…of parallelism is controlled by the number of shards. — Q9 select Year ,count…
…to several tables or perform complex queries finding relationships between objects. Normalized structure and a lot of joins is right way to design your database…number of CPUs will not help. Sometimes it is good idea to manually split query into several, run in…
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