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
Give a man a fish, and he eats for a day.
Hit him with a fish, and he goes away for good!
