…for MySQL, but note that SchemaSpy works for pretty much all the popular RDBMS out there. java -jar schemaSpy_5.0.0.jar -t mysql…Tables – Names, number of children, parents, count of columns, row counts, and comments — a great way for a high level overview of the table…
Post: MySQL Query Patterns, Optimized - Webinar questions followup
June 3, 2013 By 2 Comments
… irregular distribution of matching rows that you’ll get skewed results. For instance, if there’…table to count the movies per production year for each kind_id. It was more efficient in this case to force MySQL… this, so it pays to test all different solutions, and measure the resulting performance! …
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
…all nodes, we can (simultaneously) establish global ordering for the transaction, so by the time the original node gets…rows. When a player makes an achievement, your application updates this table with a statement like this: UPDATE achievements SET count = count…
Post: Understanding the maximum number of columns in a MySQL table
April 8, 2013 By 5 Comments
…table_options),reclength); if (info_length+(ulong) create_fields.elements*FCOMP+288+ n_length+int_length+com_length > 65535L || int_count…all comments (in bytes) + length of all intervals (for…gets you a 46kb CREATE TABLE statement and a 76kb FRM file for a table…for a table in MySQL…
Post: Virident vCache vs. FlashCache: Part 2
May 17, 2013 By 3 Comments
…for all of the benchmarks on both systems. The benchmark tool used was sysbench 0.5 and the version of MySQL…MySQL & Benchmark Configuration All benchmarks were conducted with the following: sysbench –num-threads=32 –test=tests/db/oltp.lua –oltp_tables_count=32 \ –oltp-table…
Post: How FLUSH TABLES WITH READ LOCK works with Innodb Tables
March 23, 2012 By 20 Comments
…all (use mysql -A in this case, to prevent it from getting field list from all tables…
Post: The case for getting rid of duplicate “sets”
May 17, 2011 By 2 Comments
… for you to notice an effective change. Lets say I have a table of numbers, and I want to sum them all up: mysql… table in the database by removing the duplicates: mysql> create table ex2 as select val, count(*) from ex1 group by val; Query OK, 9 rows… index on this table. mysql> delete from data where val=16; Query OK, 1 row affected (3.14 sec) mysql> select val, count(distinct id…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 141 Comments
…table. The times for full table scan vs range scan by index: mysql> select count(pad) from large; +————+ | count(pad) | +————+ | 31457280 | +————+ 1 row…for all kinds of applications, however for OLTP applications with queries examining only few rows…
Post: How to find MySQL queries worth optimizing ?
September 11, 2012 By 6 Comments
… amount of rows as they end up sending. In this case if I index the table I get the… actual rows which are found and returned up to the top level MySQL part for processing are counted the Rows_examined … this query in a simple way because scanning all that rows are actually needed to produce group by …
Post: Efficient Boolean value storage for Innodb Tables
April 23, 2008 By 6 Comments
…for MyISAM for same tables: mysql> show table status like “%bool%” \G *************************** 1. row *************************** Name: bbool Engine: MyISAM Version: 10 Row_format: Fixed Rows: 2097152 Avg_row…
