ENG-4681 [YSQL] Support INTERVAL for date/time datatypes

Summary: Support for INTERVAL type - stored as 128 bit len binary in DocDB

Test Plan: Adapted yb_interval pr_regress tests from PostgreSQL

Reviewers: mihnea, hector, alex, neil

Reviewed By: alex, neil

Subscribers: neha

Differential Revision: https://phabricator.dev.yugabyte.com/D6277

src/postgres/src/backend/catalog/ybctype.c

@@ -74,6 +74,7 @@
 #include "utils/syscache.h"
 #include "utils/numeric.h"
 #include "utils/uuid.h"
+#include "utils/timestamp.h"
 
 #include "yb/yql/pggate/ybc_pggate.h"
 
@@ -423,6 +424,26 @@ Datum YBCTimeToDatum(const int64 *data, int64 bytes, const YBCPgTypeAttrs *type_
 	return TimeADTGetDatum(*data);
 }
 
+/*
+ * INTERVAL conversions.
+ * PG represents INTERVAL as 128 bit structure, store it as binary
+ */
+void YBCDatumToInterval(Datum datum, void **data, int64 *bytes) {
+  *data = DatumGetIntervalP(datum);
+  *bytes = sizeof(Interval);
+}
+
+Datum YBCIntervalToDatum(const void *data, int64 bytes, const YBCPgTypeAttrs *type_attrs) {
+  const size_t sz = sizeof(Interval);
+  if (bytes != sz) {
+    ereport(ERROR, (errcode(ERRCODE_DATA_CORRUPTED),
+        errmsg("Unexpected size for Interval (%ld)", bytes)));
+  }
+  Interval* result = palloc(sz);
+  memcpy(result, data, sz);
+  return IntervalPGetDatum(result);
+}
+
 /*
  * Other conversions.
  */
@@ -656,9 +677,9 @@ static const YBCPgTypeEntity YBCTypeEntityTable[] = {
 		(YBCPgDatumToData)YBCDatumToInt64,
 		(YBCPgDatumFromData)YBCInt64ToDatum },
 
-	{ INTERVALOID, YB_YQL_DATA_TYPE_NOT_SUPPORTED, false,
-		(YBCPgDatumToData)NULL,
-		(YBCPgDatumFromData)NULL },
+	{ INTERVALOID, YB_YQL_DATA_TYPE_BINARY, true,
+		(YBCPgDatumToData)YBCDatumToInterval,
+		(YBCPgDatumFromData)YBCIntervalToDatum },
 
 	{ TIMETZOID, YB_YQL_DATA_TYPE_NOT_SUPPORTED, false,
 		(YBCPgDatumToData)NULL,

src/postgres/src/backend/parser/gram.y

@@ -13174,13 +13174,11 @@ SimpleTypename:
 			| ConstDatetime	{ $$ = $1; }
 			| ConstInterval opt_interval
 				{
-					parser_ybc_not_support(@1, "Interval");
 					$$ = $1;
 					$$->typmods = $2;
 				}
 			| ConstInterval '(' Iconst ')'
 				{
-					parser_ybc_not_support(@1, "Interval");
 					$$ = $1;
 					$$->typmods = list_make2(makeIntConst(INTERVAL_FULL_RANGE, -1),
 											 makeIntConst($3, @3));
@@ -13496,7 +13494,6 @@ ConstDatetime:
 ConstInterval:
 			INTERVAL
 				{
-					parser_ybc_not_support(@1, "INTERVAL");
 					$$ = SystemTypeName("interval");
 					$$->location = @1;
 				}

src/postgres/src/test/regress/expected/yb_date.out

@@ -1153,30 +1153,30 @@ SELECT EXTRACT(CENTURY FROM TIMESTAMP '1970-03-20 04:30:00.00000'); -- 20
 (1 row)
 
 -- on an interval
--- TODO: Enable once we start supporting INTEREVAL - ENG-4681 (part of issue #711)
--- SELECT EXTRACT(CENTURY FROM INTERVAL '100 y');  -- 1
--- date_part
--- -----------
--- 1
--- (1 row)
---
--- SELECT EXTRACT(CENTURY FROM INTERVAL '99 y');   -- 0
--- date_part
--- -----------
--- 0
--- (1 row)
---
--- SELECT EXTRACT(CENTURY FROM INTERVAL '-99 y');  -- 0
--- date_part
--- -----------
--- 0
--- (1 row)
---
--- SELECT EXTRACT(CENTURY FROM INTERVAL '-100 y'); -- -1
--- date_part
--- -----------
--- -1
--- (1 row)
+SELECT EXTRACT(CENTURY FROM INTERVAL '100 y');  -- 1
+ date_part
+-----------
+         1
+(1 row)
+
+SELECT EXTRACT(CENTURY FROM INTERVAL '99 y');   -- 0
+ date_part
+-----------
+         0
+(1 row)
+
+SELECT EXTRACT(CENTURY FROM INTERVAL '-99 y');  -- 0
+ date_part
+-----------
+         0
+(1 row)
+
+SELECT EXTRACT(CENTURY FROM INTERVAL '-100 y'); -- -1
+ date_part
+-----------
+        -1
+(1 row)
+
 --
 -- test trunc function!
 --