Re: Stats target increase vs compute_tsvector_stats()

I don't quote know how this data but any constant factor seems like it  
would be arbitrary. It sounds like a more principled algorithm would  
be to use stats_target^2. But that has the same problem. Even  
stats_target^1.5 would be too big for stats_target 10,000.

I think just using 10 is probably the right thing.

-- 
Greg


On 13 Dec 2008, at 13:02, Tom Lane <tgl@sss.pgh.pa.us> wrote:

> I started making the changes to increase the default and maximum stats
> targets 10X, as I believe was agreed to in this thread:
> http://archives.postgresql.org/pgsql-hackers/2008-12/msg00386.php
>
> I came across this bit in ts_typanalyze.c:
>
>    /* We want statistic_target * 100 lexemes in the MCELEM array */
>    num_mcelem = stats->attr->attstattarget * 100;
>
> I wonder whether the multiplier here should be changed?  This code is
> new for 8.4, so we have zero field experience about what desirable
> lexeme counts are; but the prospect of up to a million lexemes in
> a pg_statistic entry doesn't seem quite right.  I'm tempted to cut the
> multiplier to 10 so that the effective range of MCELEM sizes remains
> the same as what Jan had in mind when he wrote the code.
>
>            regards, tom lane
>
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