Optimize jsonb returning, Json allocation

Nikita Glukhov · Nikita Glukhov · commit 8c8ced1ed7d2 · 2022-07-27T01:02:30.000+03:00
diff --git a/src/backend/utils/adt/jsonb_util.c b/src/backend/utils/adt/jsonb_util.c
@@ -2715,6 +2715,9 @@ 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/include/utils/json_generic.h b/src/include/utils/json_generic.h
@@ -110,7 +110,7 @@ typedef JsonContainer JsonbContainer;
 #else
 #define PG_GETARG_JSONB_P(n)		DatumGetJsonbP(PG_GETARG_DATUM(n), alloca(sizeof(Json)), false) /* FIXME conditional alloca() */
 #endif
-#define PG_GETARG_JSONB_PC(n)		DatumGetJsonbPC(PG_GETARG_DATUM(n), 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_JSONB_P_COPY(x)	DatumGetJsonbPCopy(PG_GETARG_DATUM(x))
 
 #define PG_FREE_IF_COPY_JSONB(json, n) JsonFree(json)

Original file line number	Diff line number	Diff line change
`@@ -2715,6 +2715,9 @@ DatumGetJsonbPC(Datum datum, Json *tmp, bool copy)`
`2715`	`2715`	`datum = PointerGetDatum(pg_detoast_datum_copy(src));`
`2716`	`2716`	`}`
`2717`	`2717`
	`2718`	`+ if (!jsonb_partial_decompression)`
	`2719`	`+ return DatumGetJson(datum, &jsonbContainerOps, tmp);`
	`2720`	`+`
`2718`	`2721`	`CompressedDatumInit(&cd, datum);`
`2719`	`2722`
`2720`	`2723`	`if (!cd.compressed)`