Re: fairly current mysql v postgresql comparison need for - Mailing list pgsql-general

From Mike Mascari
Subject Re: fairly current mysql v postgresql comparison need for
Date
Msg-id 3E7F763B.5040200@mascari.com
Whole thread Raw
In response to Re: fairly current mysql v postgresql comparison need for  (Bruce Momjian <pgman@candle.pha.pa.us>)
List pgsql-general
Bruce Momjian wrote:
> Supposedly MySQL did add MVCC in some fashion, so I assume that's how
> they would do it.

Yep. The row-level locking remark threw me. According to 7.5.8
of their docs:

"In the InnoDB transaction model the goal has been to combine
the best properties of a multi-versioning database to
traditional two-phase locking. InnoDB does locking on row level
and runs queries by default as non-locking consistent reads, in
the style of Oracle. The lock table in InnoDB is stored so
space-efficiently that lock escalation is not needed: typically
several users are allowed to lock every row in the database, or
any random subset of the rows, without InnoDB running out of
memory."

Now I'm not sure why someone would need InnoDB Hot Backup:

http://www.innodb.com/hotbackup.html

when the --single-transaction option to mysqldump would provide
a consistent snapshot.

Mike Mascari
mascarm@mascari.com


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