Re: trouble with the automatic indexes on CREATE TABLE

From: Bill McGonigle <mcgonigle(at)medicalmedia(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: trouble with the automatic indexes on CREATE TABLE
Date: 2001-05-16 14:49:12
Message-ID: 200105161448.f4GEmhA14158@postgresql.org
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Excellent. Thanks.

There is one discussion of NAMEDATALEN in the archives, pertaining to
version 6.4.2. That discussion brings up a few questions/assumptions
related to getting this to work reliably. I'd love to hear any
comments/corrections/amplifications:

1) It was required that OIDNAMELEN be set to sizeof(Oid) + NAMEDATALEN.
Looking through the 7.1 source tree, OID_MAX is now set to UINT_MAX,
which should be plenty big. :) Should I change anything else?

2) NAMEDATALEN is defined in the ODBC sources. I found a message saying
this was used in the 6.2 protocol but not the 6.3 protocol - Is it safe to
assume it's not used in the version 7 protocol either? I'd hate to have
to dig out a Windows box to recompile the driver. ;)

3) Will psql from another machine fail to work if that machine's pgsql
hasn't been compiled with the modified MAXDATALEN? Is this the same
question as (2)?

4) If 3 is yes, maybe negotiating MAXDATALEN in the protocol would be a
good idea?

5) If we assume equal lengths for table and column names (for the sake of
argument), when a UNIQUE constraint is present, the effective non-unique
length of a column name in pgsql, as distributed, is about 12 characters
(31-'__' -'__key')? Isn't that kind of short? If there is a replacement
for OIDNAMELEN, NAMEDATALEN could be set to 248 and both could still be
under 256 on a 64-bit machine.

I'm going to give it a whirl anyway - I just don't want to get stung later.

Thanks,
-Bill

On Tuesday, May 15, 2001, at 06:47 PM, Tom Lane wrote:

> If you want to use names like that, you'd be well advised to increase
> NAMEDATALEN. See the archives.

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