Re: USING HASH considered harmful?

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> We've just discovered a rather nasty feature of hashes, namely that
> simultaneous reads & writes to a single row will deadlock if there
> is a hash index on the table.
>
> I guess this is because PG really has to lock the hash table entry in
> both cases. It does, however, make HASH indices completely useless for
> any table that you might want to update.
>
> Is this a known feature?

Yes, I have heard about this problem.  Would you test btree vs hash and
report back which is faster.  I have requested this from >20 people and
no one reported back.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
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