Re: TEXT vs PG_NODE_TREE in system columns (cross column and expression statistics patch)

Excerpts from Boszormenyi Zoltan's message of jue abr 28 11:03:56 -0300 2011:

> My question is that why pg_node_tree is unusable as
> syscache attribute? I attempted to alias it as text in the patch
> but I get the following error if I try to use it by setting
> USE_SYSCACHE_FOR_SEARCH to 1 in selfuncs.c.
> Directly using the underlying pg_statistic3 doesn't cause an error.
>
> zozo=# select * from t1 where i+1 = 5;
> ERROR: could not determine which collation to use for string comparison
> HINT: Use the COLLATE clause to set the collation explicitly.

Maybe the pg_node_tree problem is a bug with the collation feature. If
you could reproduce it in unpatched master, I'm sure it'd find a quick
death.

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Álvaro Herrera <alvherre(at)commandprompt(dot)com>
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