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Doc: remove claim that hash index creation depends on effective_cache_size.

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This text was added by commit ff213239c, and not long thereafter obsoleted
by commit 4adc2f72a (which made the test depend on NBuffers instead); but
nobody noticed the need for an update.  Commit 9563d5b5e adds some further
dependency on maintenance_work_mem, but the existing verbiage seems to
cover that with about as much precision as we really want here.  Let's
just take it all out rather than leaving ourselves open to more errors of
omission in future.  (That solution makes this change back-patchable, too.)

Noted by Peter Geoghegan.

Discussion: <CAM3SWZRVANbj9GA9j40fAwheQCZQtSwqTN1GBTVwRrRbmSf7cg@mail.gmail.com>
This commit is contained in:
Tom Lane 2016-07-31 18:32:34 -04:00
parent a9ed875fdc
commit 11653cd87f
1 changed files with 1 additions and 10 deletions
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11
doc/src/sgml/ref/create_index.sgml
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@ -568,16 +568,7 @@ Indexes:
dependent on the setting of <xref linkend="guc-maintenance-work-mem">.
Larger values will reduce the time needed for index creation, so long
as you don't make it larger than the amount of memory really available,
which would drive the machine into swapping. For hash indexes, the
value of <xref linkend="guc-effective-cache-size"> is also relevant to
index creation time: <productname>PostgreSQL</productname> will use one
of two different hash index creation methods depending on whether the
estimated index size is more or less than <varname>effective_cache_size</>.
For best results, make sure that this parameter is also set to something
reflective of available memory, and be careful that the sum of
<varname>maintenance_work_mem</> and <varname>effective_cache_size</> is
less than the machine's RAM less whatever space is needed by other
programs.
which would drive the machine into swapping.
</para>
<para>