Martijn van Oosterhout wrote:
On Wed, Mar 07, 2007 at 02:43:39AM +1030, Shane Ambler wrote:
I think a way can be devised to maintain the primary key and unique
constraints.
If a search is done on the parent table, the planner knows to rewrite
the query as a union (or union all) of all child tables that relate to
the where clause, or all child tables if the where clause is not on the
column/s used to partition, then this concept should be able to be
converted to indexes as well, so that when a primary or unique index
from a child table is inserted to, then each of the related child
indexes is consulted to ensure uniqueness.
But that's where it breaks down: you not only need to check that the
row you're inserting is unique, you need to make sure that other people
trying to insert the same value see it.
This sounds like what is really needed is a way to lock a certain
condition, namely the existance or non-existance of a record with
certain values in certain fields. This would not only help this case,
it would also help RI triggers, because those wouldn't have to acquire
a share lock on the referenced rows anymore.
As you pointed out, this would also make unique GiST indices possible
No real idea how to do this, though :-(
greetings, Florian Pfluge
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