Parallel executor support.

This code provides infrastructure for a parallel leader to start up
parallel workers to execute subtrees of the plan tree being executed
in the master.  User-supplied parameters from ParamListInfo are passed
down, but PARAM_EXEC parameters are not.  Various other constructs,
such as initplans, subplans, and CTEs, are also not currently shared.
Nevertheless, there's enough here to support a basic implementation of
parallel query, and we can lift some of the current restrictions as
needed.

Amit Kapila and Robert Haas

1 files changed, 10 insertions, 0 deletions

diff --git a/src/include/utils/datum.h b/src/include/utils/datum.h
index c572f790a50..e9d4be5c4ba 100644
--- a/src/include/utils/datum.h
+++ b/src/include/utils/datum.h
@@ -46,4 +46,14 @@ extern Datum datumTransfer(Datum value, bool typByVal, int typLen);
 extern bool datumIsEqual(Datum value1, Datum value2,
 			 bool typByVal, int typLen);
 
+/*
+ * Serialize and restore datums so that we can transfer them to parallel
+ * workers.
+ */
+extern Size datumEstimateSpace(Datum value, bool isnull, bool typByVal,
+				   int typLen);
+extern void datumSerialize(Datum value, bool isnull, bool typByVal,
+			   int typLen, char **start_address);
+extern Datum datumRestore(char **start_address, bool *isnull);
+
 #endif   /* DATUM_H */