Added to TODO:

        * Cache last known per-tuple offsets to speed long tuple access


Tom Lane wrote:
> Hannu Krosing <[EMAIL PROTECTED]> writes:
> >> i.e. for tuple with 100 cols, allocate an array of 100 pointers, plus
> >> keep count of how many are actually valid,
> > Additionally, this should also make repeted determining of NULL fields
> > faster - just put a NULL-pointer in and voila - no more bit-shifting and
> > AND-ing to find out if the field is null.
> Right, the output of the operation would be a pair of arrays: Datum
> values and is-null flags.  (NULL pointers don't work for pass-by-value
> datatypes.)
> I like the idea of keeping track of a last-known-column position and
> incrementally extending that as needed.
> I think the way to manage this is to add the overhead data (the output
> arrays and last-column state) to TupleTableSlots.  Then we'd have
> a routine similar to heap_getattr except that it takes a TupleTableSlot
> and makes use of the extra state data.  The infrastructure to manage
> the state data is already in place: for example, ExecStoreTuple would
> reset the last-known-column to 0, ExecSetSlotDescriptor would be
> responsible for allocating the output arrays using the natts value from
> the provided tupdesc, etc.
> This wouldn't help for accesses that are not in the context of a slot,
> but certainly all the ones from ExecEvalVar are.  The executor always
> works with tuples stored in slots, so I think we could fix all the
> high-traffic cases this way.
>                       regards, tom lane
> ---------------------------(end of broadcast)---------------------------
> TIP 6: Have you searched our list archives?

  Bruce Momjian                        |
  [EMAIL PROTECTED]               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

---------------------------(end of broadcast)---------------------------
TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]

Reply via email to