1,892 reputation
58
bio website mysql.rjweb.org
location California
age
visits member for 3 years, 6 months
seen Jun 17 at 2:38
  • Using MySQL for over a decade, starting before version 4.0.

  • Enjoy designing 'huge' databases.

  • Hang out in forums.mysql.com (a lot more traffic there than here).

  • Been programming since before the invention of Unix or SQL.

My documents and tips: http://mysql.rjweb.org/


Sep
24
awarded  Autobiographer
Sep
5
awarded  Nice Answer
May
20
awarded  Yearling
Jan
26
answered Automobile database logic
Jan
26
comment MySQL aggregation count performance
How big is the table? What Engine are you using? Please provide SHOW CREATE TABLE. If year is NOT NULL, you could use COUNT(*) instead of COUNT(year).
Jan
26
comment SQL queries are very slow
Please provide SHOW CREATE TABLE -- it is much more descriptive than DESCRIBE or EXPLAIN. "intersect" is often the fallback for having two separate indexes, when a "compound" index would be better.
Jan
26
comment MySQL Query: Delete from 'table2' where column = 'value' IF column in 'table1' = 'value'
You could also use the "multi-table delete" syntax. It might run faster than EXISTS. (It might need LEFT JOIN.)
Jan
26
comment MySQL Query: Delete from 'table2' where column = 'value' IF column in 'table1' = 'value'
"gender int(11) NOT NULL default '0'," says that you are allowing for 2 billion different genders! Suggest TINYINT that that and many other fields -- saves space, hence speeds up things.
Jan
26
answered Mysql query is very slow
Jan
26
answered Reasons for occasionally slow queries?
Jan
21
answered Poor SQL performance with raid10
Oct
23
answered Slow query responce on different mysql versions, percona, MariaDB
Oct
23
answered Just how much is a query supposed to slow down the whole system?
May
20
awarded  Yearling
Jan
19
awarded  mysql
Jan
8
answered mysql 5 vs 5.5 memory usage
Jan
8
comment What is the best and most performant MySQL cloud solution?
How many SQL statements were in the 22 min (or 8 min) benchmark? 1000 sql statements (even simple ones) takes about 3 minutes, just for hopping across the 'pond' (Atlantic Ocean). Rule of thumb: Cross-country: 100ms latency per query; cross-pond: 200ms; worst: 300ms.
Jan
8
answered Is it bad to create many mysql temporary tables simultaneously?
Jan
8
comment Is it bad to create many mysql temporary tables simultaneously?
Implicit temp tables have no impact on replication, whether SBR or RBR. Explicit temp tables send all the DDLs across the wire.
Jan
8
comment How to select data in a sub query only once?
IN ( SELECT ... ) is very poorly optimized (until about 5.6.7); do not use it. EXISTS ( SELECT ... ) is reasonably well optimized. LEFT JOIN ... IS [NOT] NULL is also well optimized.