Re: Merge Tables and Replication

[Raj Shekhar <rajlist@xxxxxxxxxxxxxx>]

dpgirago@xxxxxxxxxxxxxx wrote:

>  
> Does this sound about right? Anybody see any road hazards? If not, and
> this line of thinking is reasonable, should the DB with the older records
> also be replicated so that when a new old records table needs to be
> created, I don't have to repeat everything on the slave?
> 

Most of the problems documented here
<http://dev.mysql.com/doc/refman/5.0/en/merge-table-problems.html> and
some of it here
<http://dev.mysql.com/doc/refman/5.0/en/merge-storage-engine.html>

The problems that stand out

 - A MERGE table cannot maintain uniqueness constraints over the
   entire table.

 - Key reads are slower. When you read a key, the MERGE storage engine
   needs to issue a read on all underlying tables to check which one
   most closely matches the given key. To read the next key, the MERGE
   storage engine needs to search the read buffers to find the next
   key.

-- 
raj shekhar
facts: http://rajshekhar.net | opinions: http://rajshekhar.net/blog
Yoda of Borg are we: Futile is resistance. Assimilate you, we will
'Borg? Sounds Swedish.' - Lily, Star Trek First Contact


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