On 2016/01/12 18:00, Etsuro Fujita wrote:
On 2016/01/12 2:36, Alvaro Herrera wrote:
I wonder,
--- 2166,2213 ----
}
/*
! * If rel is a base relation, detect whether any system columns
are
! * requested from the rel. (If rel is a join relation,
rel->relid will be
! * 0, but there can be no Var in the target list with relid 0,
so we skip
! * this in that case. Note that any such system columns are
assumed to be
! * contained in fdw_scan_tlist, so we never need fsSystemCol to
be true in
! * the joinrel case.) This is a bit of a kluge and might go
away someday,
! * so we intentionally leave it out of the API presented to FDWs.
*/
! scan_plan->fsSystemCol = false;
! if (scan_relid > 0)
{
! Bitmapset *attrs_used = NULL;
! ListCell *lc;
! int i;
! /*
! * First, examine all the attributes needed for joins or
final output.
! * Note: we must look at reltargetlist, not the attr_needed
data,
! * because attr_needed isn't computed for inheritance child
rels.
! */
! pull_varattnos((Node *) rel->reltargetlist, scan_relid,
&attrs_used);
! /* Add all the attributes used by restriction clauses. */
! foreach(lc, rel->baserestrictinfo)
{
! RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
!
! pull_varattnos((Node *) rinfo->clause, scan_relid,
&attrs_used);
}
! /* Now, are any system columns requested from rel? */
! for (i = FirstLowInvalidHeapAttributeNumber + 1; i < 0; i++)
! {
! if (bms_is_member(i -
FirstLowInvalidHeapAttributeNumber, attrs_used))
! {
! scan_plan->fsSystemCol = true;
! break;
! }
! }
!
! bms_free(attrs_used);
! }
return scan_plan;
}
Would it make sense to call pull_varattnos(reltargetlist), then walk the
bitmapset and break if we see a system column, then call
pull_varattnos() on the rinfo->clause? That way, if the targetlist
request a system column we don't have to walk the RestrictInfos.
Seems like a good idea. Will update the patch.
Done. Attached is an updated version of the patch.
Best regards,
Etsuro Fujita
*** a/src/backend/optimizer/plan/createplan.c
--- b/src/backend/optimizer/plan/createplan.c
***************
*** 2097,2106 **** create_foreignscan_plan(PlannerInfo *root, ForeignPath *best_path,
RelOptInfo *rel = best_path->path.parent;
Index scan_relid = rel->relid;
Oid rel_oid = InvalidOid;
- Bitmapset *attrs_used = NULL;
Plan *outer_plan = NULL;
- ListCell *lc;
- int i;
Assert(rel->fdwroutine != NULL);
--- 2097,2103 ----
***************
*** 2169,2204 **** create_foreignscan_plan(PlannerInfo *root, ForeignPath *best_path,
}
/*
! * Detect whether any system columns are requested from rel. This is a
! * bit of a kluge and might go away someday, so we intentionally leave it
! * out of the API presented to FDWs.
! *
! * First, examine all the attributes needed for joins or final output.
! * Note: we must look at reltargetlist, not the attr_needed data, because
! * attr_needed isn't computed for inheritance child rels.
*/
! pull_varattnos((Node *) rel->reltargetlist, rel->relid, &attrs_used);
!
! /* Add all the attributes used by restriction clauses. */
! foreach(lc, rel->baserestrictinfo)
{
! RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
! pull_varattnos((Node *) rinfo->clause, rel->relid, &attrs_used);
! }
! /* Now, are any system columns requested from rel? */
! scan_plan->fsSystemCol = false;
! for (i = FirstLowInvalidHeapAttributeNumber + 1; i < 0; i++)
! {
! if (bms_is_member(i - FirstLowInvalidHeapAttributeNumber, attrs_used))
{
! scan_plan->fsSystemCol = true;
! break;
}
- }
! bms_free(attrs_used);
return scan_plan;
}
--- 2166,2229 ----
}
/*
! * If rel is a base relation, detect whether any system columns are
! * requested from the rel. (If rel is a join relation, rel->relid will be
! * 0, but there can be no Var with relid 0 in the reltargetlist or the
! * restriction clauses, so we skip this in that case. Note that any such
! * columns in base relations that were joined are assumed to be contained
! * in fdw_scan_tlist.) This is a bit of a kluge and might go away someday,
! * so we intentionally leave it out of the API presented to FDWs.
*/
! scan_plan->fsSystemCol = false;
! if (scan_relid > 0)
{
! Bitmapset *attrs_used = NULL;
! ListCell *lc;
! int i;
! /*
! * First, examine all the attributes needed for joins or final output.
! * Note: we must look at reltargetlist, not the attr_needed data,
! * because attr_needed isn't computed for inheritance child rels.
! */
! pull_varattnos((Node *) rel->reltargetlist, scan_relid, &attrs_used);
! /* Are any system columns requested from rel? */
! for (i = FirstLowInvalidHeapAttributeNumber + 1; i < 0; i++)
{
! if (bms_is_member(i - FirstLowInvalidHeapAttributeNumber, attrs_used))
! {
! scan_plan->fsSystemCol = true;
! break;
! }
}
! /* Examine all the attributes used by restriction clauses, if needed */
! if (!scan_plan->fsSystemCol)
! {
! foreach(lc, rel->baserestrictinfo)
! {
! RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
!
! pull_varattnos((Node *) rinfo->clause, scan_relid, &attrs_used);
!
! /* Are any system columns requested from rel? */
! for (i = FirstLowInvalidHeapAttributeNumber + 1; i < 0; i++)
! {
! if (bms_is_member(i - FirstLowInvalidHeapAttributeNumber, attrs_used))
! {
! scan_plan->fsSystemCol = true;
! break;
! }
! }
!
! if (scan_plan->fsSystemCol)
! break;
! }
! }
!
! bms_free(attrs_used);
! }
return scan_plan;
}
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