Re: Reduction in WAL for UPDATEs - Mailing list pgsql-hackers

From Zeugswetter Andreas ADI SD
Subject Re: Reduction in WAL for UPDATEs
Date
Msg-id E1539E0ED7043848906A8FF995BDA57901E7B00A@m0143.s-mxs.net
Whole thread Raw
In response to Re: Reduction in WAL for UPDATEs  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Reduction in WAL for UPDATEs  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
> > I agree that these values need a second look. I think a
> > TOAST_TUPLE_THRESHOLD well smaller than the current value would
still
> > easily pay its way. With a little caution to avoid wasting too much
> > effort on the last few bytes I suspect even as low as
> 400-500 bytes is probably worthwhile.

But a seq scan (or non cached access) would suddenly mutate to multiple
random accesses, so this is not a win-win situation.

Btw: Do we consider the existance of toasted columns in the seq-scan
cost estimation ?

Andreas


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