Optimize jsonb returning, Json allocation

Nikita Glukhov · Nikita Glukhov · commit d03a62e73315 · 2021-01-14T22:48:41.000Z
diff --git a/src/backend/utils/adt/jsonb_util.c b/src/backend/utils/adt/jsonb_util.c
@@ -2911,6 +2911,9 @@ DatumGetJsonbPC(Datum datum, Json *tmp, bool copy)
 			datum = PointerGetDatum(pg_detoast_datum_copy(src));
 	}
 
+	if (!jsonb_partial_decompression)
+		return DatumGetJson(datum, &jsonbContainerOps, tmp);
+
 	CompressedDatumInit(&cd, datum);
 
 	if (!cd.compressed)
diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c
@@ -644,7 +644,7 @@ jsonb_object_field(PG_FUNCTION_ARGS)
 												 PG_GETARG_TEXT_PP(1));
 
 	if (res)
-		PG_RETURN_JSONB_P(JsonbValueToJsonb(res));
+		PG_RETURN_JSONB_VALUE(res);
 	else
 		PG_RETURN_NULL();
 }
diff --git a/src/include/utils/json_generic.h b/src/include/utils/json_generic.h
@@ -97,6 +97,8 @@ typedef struct Json
 #define JsonbPGetDatum(json)		JsonFlattenToJsonbDatum(JsonGetUniquified(json))
 #define JsontPGetDatum(json)		CStringGetTextDatum(JsonToCString(JsonRoot(json), NULL))
 
+#define JsonValueGetJsonbDatum(json)		PointerGetDatum(JsonValueFlatten(json, JsonbEncode, &jsonbContainerOps))
+
 #ifdef JsonxPGetDatum
 # define JsonGetDatum(json)			JsonxPGetDatum(json)
 #else
@@ -117,6 +119,7 @@ typedef struct Json
 #undef PG_RETURN_JSONB_P
 #define PG_RETURN_JSONB_P(x)		PG_RETURN_DATUM(JsonGetDatum(x))
 #define PG_RETURN_JSONT_P(x)		PG_RETURN_DATUM(JsontPGetDatum(x))
+#define PG_RETURN_JSONB_VALUE(x)	PG_RETURN_DATUM(JsonValueGetJsonbDatum(x))
 
 #define PG_GETARG_JSONX_TMP(n, tmp)	DatumGetJsonxTmp(PG_GETARG_DATUM(n), tmp)
 
@@ -126,7 +129,7 @@ typedef struct Json
 #else
 #define PG_GETARG_JSONB_P(n)		PG_GETARG_JSONX_TMP(n, alloca(sizeof(Json))) /* FIXME conditional alloca() */
 #endif
-#define PG_GETARG_JSONB_PC(n)		DatumGetJsonbPC(PG_GETARG_DATUM(n), NULL /*alloca(sizeof(Json))*/, false) /* FIXME conditional alloca() */
+#define PG_GETARG_JSONB_PC(n)		DatumGetJsonbPC(PG_GETARG_DATUM(n), alloca(JsonAllocSize(16)) /* FIXME sizeof CompressedJsonb */, false)
 #define PG_GETARG_JSONT_P(n)		DatumGetJsontP(PG_GETARG_DATUM(n))
 
 #undef	PG_GETARG_JSONB_P_COPY

Original file line number	Diff line number	Diff line change
`@@ -2911,6 +2911,9 @@ DatumGetJsonbPC(Datum datum, Json *tmp, bool copy)`
`2911`	`2911`	`datum = PointerGetDatum(pg_detoast_datum_copy(src));`
`2912`	`2912`	`}`
`2913`	`2913`
	`2914`	`+ if (!jsonb_partial_decompression)`
	`2915`	`+ return DatumGetJson(datum, &jsonbContainerOps, tmp);`
	`2916`	`+`
`2914`	`2917`	`CompressedDatumInit(&cd, datum);`
`2915`	`2918`
`2916`	`2919`	`if (!cd.compressed)`
Original file line number	Diff line number	Diff line change
`@@ -644,7 +644,7 @@ jsonb_object_field(PG_FUNCTION_ARGS)`
`644`	`644`	`PG_GETARG_TEXT_PP(1));`
`645`	`645`
`646`	`646`	`if (res)`
`647`		`- PG_RETURN_JSONB_P(JsonbValueToJsonb(res));`
	`647`	`+ PG_RETURN_JSONB_VALUE(res);`
`648`	`648`	`else`
`649`	`649`	`PG_RETURN_NULL();`
`650`	`650`	`}`