Re: operator exclusion constraints

From: Jeff Davis <pgsql(at)j-davis(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Peter Eisentraut <peter_e(at)gmx(dot)net>, Simon Riggs <simon(at)2ndquadrant(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: operator exclusion constraints
Date: 2009-11-26 09:33:49
Message-ID: 1259228029.19289.515.camel@jdavis
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On Tue, 2009-11-17 at 23:13 -0500, Robert Haas wrote:
> Forgive me if this is discussed before, but why does this store the
> strategy numbers of the relevant operators instead of the operators
> themselves? It seems like this could lead to surprising behavior if
> the user modifies the definition of the operator class.

Still open.

> I'm wondering if we can't use the existing
> BuildIndexValueDescription() rather than the new function
> tuple_as_string(). I realize there are two tuples, but maybe it makes
> sense to just call it twice?


> I'm attaching a revised doc patch for your consideration.

Thanks, I applied it. The only significant thing I changed was that I
did not inline the "index_elem" because it made it fairly hard to read.
Instead, I renamed it "exclude_elem" to make it a little more
meaningful, which I assume may have been your motivation for inlining

Changes this patch:
* doc changes
* changed constraint violation message to be more like btree unique
* improved error message when an operator is specified that doesn't
have a search strategy

Remaining issues:
* represent operator IDs in catalog, rather than strategy numbers
* if someone thinks it's an issue, support search strategies that
require binary-incompatible casts of the inputs

Jeff Davis

Attachment Content-Type Size
operator-exclusion-constraints-20091126.context.patch text/x-patch 102.3 KB

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