Re: SQL MERGE patches for PostgreSQL Versions

On Thu, Jun 22, 2017 at 11:23 AM, Craig Ringer <craig(at)2ndquadrant(dot)com> wrote:
> On 22 June 2017 at 16:05, Kang Yuzhe <tiggreen87(at)gmail(dot)com> wrote:
>> Dear PG hackers,
>>
>> First my apology if I appear to be a jerk or not following the policy.
>>
>> I emailed Boxuan Zhai who was in charge of the SQL Merge keyword in
>> 2010 of GSoC but without reply.
>>
>> I want to apply merge_v201.patch to specific PG version.
>>
>> It failed saying 1 or 2 of 5 hunk failed.
>>
>> My question is:
>> 1. Given x old patch of PG, is it possible to know to which PG
>> version can be applied?
>
> If it's produced by git-format-patch you can look at the git ref
> information in the patch. Otherwise you have to rely on what's in the
> email thread.

If you were having merge_v201.patch, how would you determine whether
it was produced by git-format-patch ow email thread?

I just downloaded the patch from GSoC site.

A code snippet from the merge_v201.patch is shown below:

diff --git a/src/backend/executor/nodeModifyTable.c
b/src/backend/executor/nodeModifyTable.c
index 8619ce3..e3ac758 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -582,6 +582,113 @@ lreplace:;
return NULL;
}

+static TupleTableSlot *
+MergeRaiseErr(void)
+{
+ elog(NOTICE, "one tuple is ERROR");
+ return NULL;
+}
+
+static TupleTableSlot *
+ExecMerge(ItemPointer tupleid,
+ TupleTableSlot *slot,
+ TupleTableSlot *planSlot,
+ MergeActionSet *actset,
+ EState *estate)
+{
+
+ TupleTableSlot *actslot = NULL;
+ ListCell *each;
+
+ /*
+ * Try the merge actions one by one until we have a match.
+ */
+ foreach(each, actset->actions)
+ {
+ ModifyTableState *mt_pstate;
+ MergeActionState *action_pstate;
+ ExprContext *econtext;
+ bool matched;
+
+ mt_pstate = (ModifyTableState *) lfirst(each);
+ Assert(IsA(mt_pstate, ModifyTableState));
+
+ /*
+ * mt_pstate is supposed to have only ONE mt_plans,
+ * which is a MergeActionState
+ */
+ action_pstate = (MergeActionState *) mt_pstate->mt_plans[0];
+ matched = ((MergeAction *)action_pstate->ps.plan)->matched;
+
+ /*
+ * If tupleid == NULL, it is a NOT MATCHED case,
+ * else, it is a MATCHED case,
+ */
+ if ((tupleid == NULL && matched) ||
+ (tupleid != NULL && !matched))
+ continue;
+
+ /* Setup the expression context. */
+ econtext = action_pstate->ps.ps_ExprContext;
+
+ /*
+ * Check that additional quals match, if any.
+ */
+ if (action_pstate->ps.qual)
+ {
+ ResetExprContext(econtext);
+
+ econtext->ecxt_scantuple = slot;
+ econtext->ecxt_outertuple = planSlot;
+
+ if (!ExecQual(action_pstate->ps.qual, econtext, false))
+ continue;
+ }
+
+ /* Ok, we have a match. Perform the action */
+
+ /* First project any RETURNING result tuple slot, if needed */
+ if (action_pstate->operation == CMD_INSERT ||
+ action_pstate->operation == CMD_UPDATE)
+ actslot = ExecProcessReturning(action_pstate->ps.ps_ProjInfo,
+ slot, planSlot);
+
+ switch (action_pstate->operation)
+ {
+ case CMD_INSERT:
+ return ExecInsert(actslot, planSlot, estate);
+
+ case CMD_UPDATE:
+ return ExecUpdate(tupleid,
+ actslot,
+ planSlot,
+ &mt_pstate->mt_epqstate,
+ estate);
+
+ case CMD_DELETE:
+ return ExecDelete(tupleid,
+ planSlot,
+ &mt_pstate->mt_epqstate,
+ estate);
+
+ case CMD_DONOTHING:
+ return NULL;
+
+ case CMD_RAISEERR:
+ return MergeRaiseErr();
+
+ default:
+ elog(ERROR, "unknown merge action type for excute");
+ break;
+ }
+ }
+
+ /*
+ * No matching action found. Perform the default action, which is
+ * RAISE ERROR.
+ */
+ return MergeRaiseErr();
+}

Now, is it possible to extract info from this code snippet whether it
was by git-format-patch or email thread?

Regards,
Zeray