On 06/01/07 16:38, PFC wrote:
>
>>>> Will the synchronized seq scan patch be able to do this by
>>>> issuing all the CREATE INDEX commands at the same time from several
>>>> different database connections ?
>>> No, but it could someday.
>
> Actually I tested, it does it right now, albeit unconsciously (pg
> doesn't do anything to synchronize the scans, but if you launch the
> concurrent connections at the same time and issue all your "create
> index" at the same time, only 1 table scan is needed). Maybe if the
> tables were bigger, it would lose sync between the 3 concurrent scans
> and would end up going slower. That's why I spoke about the
> "synchronized scan" patch.
How much of this, though, is from the OS's disk cache? Or are Seq
Scans O_DIRECT and bypass the OS cache?
>> Or would a "CREATE MANY INDEXES" (where in one statement you specify
>> all the indexes on a single table) command be easier to implement?
>
> You can get the effect right now by using concurrent connections it
> seems. Not very practical in a psql script, though...
--
Ron Johnson, Jr.
Jefferson LA USA
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Hit him with a fish, and he goes away for good!