[vox-tech] transactions (was: Unnecessary RDBMS features)
Henry House
vox-tech@lists.lugod.org
Fri, 25 Apr 2003 05:21:42 -0700
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On Thu, Apr 24, 2003 at 08:44:32PM -0700, Matt Roper wrote:
[...]
> On the other hand, if the transaction is rolled back, you simply dump
> your memory copy and there's no disk activity at all. This is a
> well-known scheme called "optimistic concurrency control," but there are
> certainly other transaction implementations that work just as well.
> Note that there's no unnecessary disk writing -- all the working copies
> are stored in memory.
Hence the commonly observed situation in which performace in large number of
INSERTs increases when autocommit is turned off---observed in PostgreSQL and
SQLite. Without a transaction block, each row would be written to disk
individually; in a transaction block all are written at once.
--=20
Henry House
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