Re: Declarative partitioning

> On 2016/04/15 18:46, Ashutosh Bapat wrote:
> >
> > 3. PartitionKeyData contains KeyTypeCollInfo, whose contents can be
> > obtained by calling functions exprType, exprTypemod on partexprs. Why do
> we
> > need to store that information as a separate member?
>
> There was no KeyTypeCollInfo in early days of the patch and then I found
> myself doing a lot of:
>
> partexprs_item = list_head(key->partexprs);
> for (attr in key->partattrs)
> {
> if (attr->attnum != 0)
> {
> // simple column reference, get type from attr
> }
> else
> {
> // expression, get type using exprType, etc.
> partexprs_item = lnext(partexprs_item);
> }
> }
>

At least the two loops can be flattened to a single loop if we keep only
expressions list with attributes being just Var nodes. exprType() etc.
would then work seemlessly.

>
> That ended up being quite a few places (though I managed to reduce the
> number of places over time). So, I created this struct which is
> initialized when partition key is built (on first open of the partitioned
> table).
>

Hmm, I am just afraid that we might end up with some code using cached
information and some using exprType, exprTypmod etc.
--
Best Wishes,
Ashutosh Bapat
EnterpriseDB Corporation
The Postgres Database Company