From: | John Siracusa <siracusa(at)mindspring(dot)com> |
---|---|
To: | Postgres Performance <pgsql-performance(at)postgresql(dot)org> |
Subject: | Re: Feature request: smarter use of conditional indexes |
Date: | 2004-03-06 21:55:33 |
Message-ID: | BC6FB305.30DCD%siracusa@mindspring.com |
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Lists: | pgsql-performance |
On 3/6/04 4:06 PM, Tom Lane wrote:
> John Siracusa <siracusa(at)mindspring(dot)com> writes:
>> So apparently all I can do is find out if it's a null test, but not if it is
>> specifically "IS NOT NULL"
>
> No, because once you have determined that the node really IsA NullTest,
> you can cast the pointer to (NullTest *) and look at the
> NullTest-specific fields.
I tried casting, but stupidly tried to access the type name (BoolTestType)
instead of the field name (nulltesttype). Duh! :)
> Think of this as poor man's object-oriented programming: Node is the supertype
> of Expr which is the supertype of NullTest (and a lot of other kinds of nodes,
> too).
Yeah, I read that in the comments but was defeated by my devious brain ;)
Thanks, I'll see how much farther I can go before getting stuck again :)
-John
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