custom statistic collector

<div class="Section1"><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-US" style="font-size:
10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-US"
style="font-size:
10.0pt;font-family:Arial">1)</span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-US"
style="font-size:
10.0pt;font-family:Arial">I want to test my own selectivity function against future stats collector. </span></font><p
class="MsoNormal"><fontface="Arial" size="2"><span lang="EN-US" style="font-size: 
10.0pt;font-family:Arial">Is this a right way to update statistic used by planner ?</span></font><p
class="MsoNormal"><fontface="Arial" size="2"><span lang="EN-US" style="font-size: 
10.0pt;font-family:Arial">update pg_statistic set
stadistinct=4,stakind3=11111,stanumbers3=array[0.8,0.2],stavalues3=array[10000,10001]where starelid=950855 and
staattnum= 21;</span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-US" style="font-size: 
10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-US"
style="font-size:
10.0pt;font-family:Arial">stadistinct values total, stakind3 is my custom STATISTIC_KIND, stanumber3 are frequencies of
stavalues3.</span></font><pclass="MsoNormal"><font face="Arial" size="2"><span lang="EN-US" style="font-size: 
10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-US"
style="font-size:
10.0pt;font-family:Arial">2)</span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-US"
style="font-size:
10.0pt;font-family:Arial">How to add custom statistic kind for 1-dim array of integers (_int4) ?</span></font><p
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10.0pt;font-family:Arial">Currently it uses standard compute_scalar_stats (commands/analyze.c).</span></font><p
class="MsoNormal"><fontface="Arial" size="2"><span lang="EN-US" style="font-size: 
10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-US"
style="font-size:
10.0pt;font-family:Arial">Custom statistic is needed to count selectivity for GIST built by contrib/intarray.
</span></font><pclass="MsoNormal"><font face="Arial" size="2"><span lang="EN-US" style="font-size: 
10.0pt;font-family:Arial">It should be gathered only for 1-dim arrays and contain most-common values met in among all
arrays,</span></font><pclass="MsoNormal"><font face="Arial" size="2"><span lang="EN-US" style="font-size: 
10.0pt;font-family:Arial">Distinct values among all arrays etc.</span></font><p class="MsoNormal"><font face="Arial"
size="2"><spanlang="EN-US" style="font-size: 
10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-US"
style="font-size:
10.0pt;font-family:Arial">Generally, it can be gathered on anyarray(not only _int4), but it’s ok for me (yet) to have
itworking for _int4 1-dim only.</span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-US"
style="font-size:
10.0pt;font-family:Arial">Pitifully, I have no idea what is the right way of putting such thing into existing
system..</span></font><pclass="MsoNormal"><font face="Arial" size="2"><span lang="EN-US" style="font-size: 
10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-US"
style="font-size:
10.0pt;font-family:Arial">Should I add switches into analyze.c or there exist a better way ?</span></font><p
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10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-US"
style="font-size:
10.0pt;font-family:Arial">Maybe one could sketch out the structure of what is to be done… </span></font><p
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10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-US"
style="font-size:
10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-US"
style="font-size:
10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-US"
style="font-size:
10.0pt;font-family:Arial"> </span></font><p class="MsoNormal"><font face="Arial" size="2"><span lang="EN-US"
style="font-size:
10.0pt;font-family:Arial"> </span></font></div>