I tested EXTERN_TUPLES_PER_PAGE for values 4(default), 2, and 1:

        4       15.596
        2       15.197
        1       14.6

which is basically a 3% decrease from 4->2 and 2->1.  The test script
and result are here:


shared_buffers again was 32MB so all the data was in memory.


Gregory Stark wrote:
> "Bruce Momjian" <[EMAIL PROTECTED]> writes:
> > Uh, am I supposed to be running more TOAST tests?  Would someone explain
> > what they want tested?
> If you want my opinion I would say we need two tests:
> We need to run the test scripts you have already for sizes that cause actual
> disk i/o. The real cost of TOAST lies in the random access seeks and your
> tests all fit in memory so they're missing that.
> Set TOAST_MAX_CHUNK_SIZE to 8k and TOAST_TOAST_TUPLE_TARGET to 4097 and store
> a large table (larger than RAM) of 4069 bytes (and verify that that's creating
> two chunks for each tuple). Test how long it takes to do a sequential scan
> with hashtext(). Compare that to the above with TOAST_MAX_CHUNK_SIZE set to 4k
> (and verify that the toast table is much smaller in this configuration).
> Actually I think we need to do the latter of these first. Because if it shows
> that bloating the toast table is faster than chopping up data into finer
> chunks then we'll want to set TOAST_MAX_CHUNK_SIZE to 8k and then your tests
> above will have to be rerun.
> -- 
>   Gregory Stark
>   EnterpriseDB          http://www.enterprisedb.com
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  Bruce Momjian  <[EMAIL PROTECTED]>          http://momjian.us
  EnterpriseDB                               http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +

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