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Resent-Message-Id: <199407141119.EAA18518@nobozo.CS.Berkeley.EDU>
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Date: Thu, 14 Jul 94 20:19:56 jst
From: wolf@molout.tutkie.tut.ac.jp (Wolf-D. Ihlenfeldt)
Message-Id: <9407141119.AA12463@molout.tutkie.tut.ac.jp>
To: postgres@postgres.Berkeley.EDU
Subject: How to interface hash access to user types
Resent-To: postgres-redist@postgres.Berkeley.EDU
Resent-Date: Thu, 14 Jul 94 04:19:03 -0700
Resent-XMts: smtp


he Postgres 4.2 documentation explains in detail
how to interface user data types to btree access methods
but seems to be completely silent about introducing a
hash access method for a user data type. Does anybody
know the necessary steps ? 
Details: I need to access unsigned 64 bit integers. I have
a comprehensive set of functions for this type, and I 
was able to define a btree access for this type. However,
I always retrieve with the '=' operator and therefore
a hash access to these numbers (which are hashcodes themselves)
might be mor effective. Currently I fail with 
WARN:Jul 14 20:30:13:IndexCatalogInformation: no amop 405 65504 1
in the query
(dbxtool) print query
`wb_dbwrite`db_write_prepare`query = "retrieve (Molecules.oid) where Molecules.E_HASHY="5F25E412BAC38683"::uint8"

with an (unprepared) hash index on the E_HASHY field.

Thank you for your help.

WDI


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