From: Robert Haas <rhaas@postgresql.org>
Date: Mon, 12 Oct 2015 15:46:40 +0000 (-0400)
Subject: Fix problems with ParamListInfo serialization mechanism.
X-Git-Url: http://git.postgresql.org/gitweb/static/maillist.html?a=commitdiff_plain;h=88f1d098644ff69900e2ca62d2695846385d54e9;p=users%2Frhaas%2Fpostgres.git

Fix problems with ParamListInfo serialization mechanism.

Commit d1b7c1ffe72e86932b5395f29e006c3f503bc53d introduced a mechanism
for serializing a ParamListInfo structure to be passed to a parallel
worker.  However, this mechanism failed to handle external expanded
values, as pointed out by Noah Misch.  Moreover, plpgsql_param_fetch
requires adjustment because the serialization mechanism needs it to skip
evaluating unused parameters just as we would do when it is called from
copyParamList, but params == estate->paramLI in that case.  To fix, do
the relevant bms_is_member test unconditionally.
---

diff --git a/src/backend/utils/adt/datum.c b/src/backend/utils/adt/datum.c
index 3d9e35442d..0d61950455 100644
--- a/src/backend/utils/adt/datum.c
+++ b/src/backend/utils/adt/datum.c
@@ -264,6 +264,11 @@ datumEstimateSpace(Datum value, bool isnull, bool typByVal, int typLen)
 		/* no need to use add_size, can't overflow */
 		if (typByVal)
 			sz += sizeof(Datum);
+		else if (VARATT_IS_EXTERNAL_EXPANDED(value))
+		{
+			ExpandedObjectHeader *eoh = DatumGetEOHP(value);
+			sz += EOH_get_flat_size(eoh);
+		}
 		else
 			sz += datumGetSize(value, typByVal, typLen);
 	}
@@ -292,6 +297,7 @@ void
 datumSerialize(Datum value, bool isnull, bool typByVal, int typLen,
 			   char **start_address)
 {
+	ExpandedObjectHeader *eoh = NULL;
 	int		header;
 
 	/* Write header word. */
@@ -299,6 +305,11 @@ datumSerialize(Datum value, bool isnull, bool typByVal, int typLen,
 		header = -2;
 	else if (typByVal)
 		header = -1;
+	else if (VARATT_IS_EXTERNAL_EXPANDED(value))
+	{
+		eoh = DatumGetEOHP(value);
+		header = EOH_get_flat_size(eoh);
+	}
 	else
 		header = datumGetSize(value, typByVal, typLen);
 	memcpy(*start_address, &header, sizeof(int));
@@ -312,6 +323,11 @@ datumSerialize(Datum value, bool isnull, bool typByVal, int typLen,
 			memcpy(*start_address, &value, sizeof(Datum));
 			*start_address += sizeof(Datum);
 		}
+		else if (eoh)
+		{
+			EOH_flatten_into(eoh, (void *) *start_address, header);
+			*start_address += header;
+		}
 		else
 		{
 			memcpy(*start_address, DatumGetPointer(value), header);
diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index c73f20b725..346e8f851c 100644
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -5696,21 +5696,17 @@ plpgsql_param_fetch(ParamListInfo params, int paramid)
 	/* now we can access the target datum */
 	datum = estate->datums[dno];
 
-	/* need to behave slightly differently for shared and unshared arrays */
-	if (params != estate->paramLI)
-	{
-		/*
-		 * We're being called, presumably from copyParamList(), for cursor
-		 * parameters.  Since copyParamList() will try to materialize every
-		 * single parameter slot, it's important to do nothing when asked for
-		 * a datum that's not supposed to be used by this SQL expression.
-		 * Otherwise we risk failures in exec_eval_datum(), not to mention
-		 * possibly copying a lot more data than the cursor actually uses.
-		 */
-		if (!bms_is_member(dno, expr->paramnos))
-			return;
-	}
-	else
+	/*
+	 * Since copyParamList() and SerializeParamList() will try to materialize
+	 * every single parameter slot, it's important to do nothing when asked for
+	 * a datum that's not supposed to be used by this SQL expression.
+	 * Otherwise we risk failures in exec_eval_datum(), not to mention
+	 * possibly copying a lot more data than the cursor actually uses.
+	 */
+	if (!bms_is_member(dno, expr->paramnos))
+		return;
+
+	if (params == estate->paramLI)
 	{
 		/*
 		 * Normal evaluation cases.  We don't need to sanity-check dno, but we