Brian Aker wrote:
Hi!
On Apr 2, 2008, at 12:35 PM, Gabriel Laden wrote:
Quote:
Fortunately MySQL is open source software, meaning we can actually
change the way it works by modifying the code. We did just that—
embedding extra information in to the MySQL replication stream that
allows us to properly update memcached in Virginia. This ensures that
the cache and the database are always in sync.
Hi there!
I have written Memcached Functions for MySQL for things like this. You
can have a setup where certain data you want to automatically be set in
memcached can be done with triggers that call these functions, depending
on what you have to store.
I have been meaning to write a users guide showing how you can leverage
these functions.
From my livejournal blog at http://capttofu.livejournal.com:
CREATE TABLE `jsoncache` (
`id` int(8) NOT NULL AUTO_INCREMENT,
`memcache_key` varchar(32) DEFAULT NULL,
`json` mediumtext,
PRIMARY KEY (`id`)
)
mysql> delimiter | mysql> CREATE TRIGGER `jsoncache_trigger` BEFORE
INSERT ON `jsoncache` FOR EACH ROW begin set @id= concat('jsoncache:',
NEW.id); set @tt= memc_set(@id, NEW.json); set NEW.memcache_key = @id; end |
Query OK, 0 rows affected (0.05 sec)
mysql>delimiter ;
mysql> insert into jsoncache (json) values ('{{json stuff}}');
Query OK, 1 row affected (0.00 sec)
mysql> select * from jsoncache;
+----+--------------+----------------+
| id | memcache_key | json |
+----+--------------+----------------+
| 1 | jsoncache:1 | {{json stuff}} |
+----+--------------+----------------+
1 row in set (0.00 sec)
mysql> select memc_get('jsoncache:1');
+-------------------------+
| memc_get('jsoncache:1') |
+-------------------------+
| {{json stuff}} |
+-------------------------+
1 row in set (0.00 sec)
Hope this helps!
--Patrick
Was this code change released by Facebook ? We have exactly such a
need for this type of setup.
No, it was not. You can emulate this behavior by using the MySQL UDF
in your queries, which is a better route to go for supportability.
http://tangent.org/586/Memcached_Functions_for_MySQL.html
Cheers,
-Brian
--
_______________________________________________________
Brian "Krow" Aker, brian at tangent.org
Seattle, Washington
http://krow.net/ <-- Me
http://tangent.org/ <-- Software
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