ok kentoku the idea is, if the client (the mysql user) use SQL_CACHE, send it to spider external servers, if SQL_NO_CACHE is used, send it to spider external servers, if SQL_CACHE and SQL_NO_CACHE aren't used, use 'query_cache_type' variable ( https://mariadb.com/kb/en/server-system-variables/#query_cache_type ) here i develop system considering a good query cache use, and i try to not depend at memcache to have a good performace (but sometimes it's very usefull), i'm testing spider engine yet, my first use is partitioning, and now i'm testing external servers as shard option, just to study, not a production use yet if you have time to create it :) no problem, could you report after a patch? i like to read mariadb internal code to understand how to use it better thanks kentoku =), tell me if i can help you 2014-06-03 16:30 GMT-03:00 kentoku <kentokushiba@gmail.com>:
Hi Roberto,
nice Colin, I read manual and got this doubt, about the query_cache option
all queries have sql_cache, or just queries that should be cached? for example...
(1)mysql user -> (2)mysql database with spider -> (3)external database considering at (1 session) and (2 global), spider query_cache = 1 (sql_cache option is passed.)
if (1) send: SELECT SQL_NO_CACHE * FROM spider_table (should not be cached) (2) will send to (3): SELECT SQL_CACHE * FROM external_spider_table (the wrong option) or : SELECT SQL_NO_CACHE * FROM spider_table ? (the right option)
Spider's query_cache option is option for each Spider table. It works adding SQL_CACHE and SQL_NO_CACHE statically, and it does not use SQL_CACHE and SQL_NO_CACHE option from user query.
maybe a "3" should be created? use SQL_CACHE option from user query?
I think it is better for creating another option for using SQL_CACHE option from user query rather than creating "3", because these options can be combined. I'll try to create it, if you need it!
Thanks, Kentoku
2014-05-30 23:24 GMT+09:00 Roberto Spadim <roberto@spadim.com.br>:
nice Colin, I read manual and got this doubt, about the query_cache option
all queries have sql_cache, or just queries that should be cached? for example...
(1)mysql user -> (2)mysql database with spider -> (3)external database considering at (1 session) and (2 global), spider query_cache = 1 (sql_cache option is passed.)
if (1) send: SELECT SQL_NO_CACHE * FROM spider_table (should not be cached) (2) will send to (3): SELECT SQL_CACHE * FROM external_spider_table (the wrong option) or : SELECT SQL_NO_CACHE * FROM spider_table ? (the right option)
maybe a "3" should be created? use SQL_CACHE option from user query?
2014-05-30 8:25 GMT-03:00 Colin Charles <colin@mariadb.org>:
On 29 May 2014, at 10:23, Roberto Spadim <roberto@spadim.com.br> wrote:
Hi guys! I'm with a doubt, spider engine don't allow query cache right? But does it use sql_cache sql_no_cache when possible?
spider has a table parameter called query_cache that sends query from spider to remote server - see: https://mariadb.com/kb/en/spider-table-system-variables/#query_cache Default is 0, that is no query cache when a select is issued on a remote server =1 passes sql_cache - result can be cached =2 sql_no_cache is passed - query result not cached that's all documented: http://dev.mysql.com/doc/refman/5.5/en/query-cache-in-select.html
I notice that in this article, https://mariadb.com/kb/en/query-cache/, the limitations do state: " • The query cache is not used by the Spider storage engine (amongst others)."
And then we have this article, https://mariadb.com/kb/en/spider-feature-matrix/ that also states spider supports the query cache - "Query Cache tuning per table of the on remote backend" - Yes
So, docs need to be clearer/in sync, since spider can't use the query cache on a spider node, but it can on a remote server -- Colin Charles, Chief Evangelist, SkySQL - The MariaDB Company blog: http://bytebot.net/blog/| t: +6-012-204-3201 | Skype: colincharles
-- Roberto Spadim SPAEmpresarial Eng. Automação e Controle
_______________________________________________ Mailing list: https://launchpad.net/~maria-discuss Post to : maria-discuss@lists.launchpad.net Unsubscribe : https://launchpad.net/~maria-discuss More help : https://help.launchpad.net/ListHelp
-- Roberto Spadim SPAEmpresarial Eng. Automação e Controle