Optimize get_jsonb_path_all avoiding an iterator

Instead of creating an iterator object at each step down the JSONB
object/array, we can just just examine its object/array flags, which is
faster.  Also, use the recently introduced JsonbValueAsText instead of
open-coding the same thing, for code simplicity.

Author: Nikita Glukhov
Discussion: https://postgr.es/m/7c417f90-f95f-247e-ba63-d95e39c0ad14@postgrespro.ru

diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c
index 01b44f5c754da350f335d7fb1e8c84237c33d7c4..aba687243422b66a958750a708b16ce6c55e9dbc 100644 (file)
--- a/src/backend/utils/adt/jsonfuncs.c
+++ b/src/backend/utils/adt/jsonfuncs.c
@@ -1329,7 +1329,6 @@ get_jsonb_path_all(FunctionCallInfo fcinfo, bool as_text)
 {
    Jsonb      *jb = PG_GETARG_JSONB_P(0);
    ArrayType  *path = PG_GETARG_ARRAYTYPE_P(1);
-   Jsonb      *res;
    Datum      *pathtext;
    bool       *pathnulls;
    int         npath;
@@ -1337,7 +1336,6 @@ get_jsonb_path_all(FunctionCallInfo fcinfo, bool as_text)
    bool        have_object = false,
                have_array = false;
    JsonbValue *jbvp = NULL;
-   JsonbValue  tv;
    JsonbContainer *container;
 
    /*
@@ -1449,41 +1447,30 @@ get_jsonb_path_all(FunctionCallInfo fcinfo, bool as_text)
 
        if (jbvp->type == jbvBinary)
        {
-           JsonbIterator *it = JsonbIteratorInit((JsonbContainer *) jbvp->val.binary.data);
-           JsonbIteratorToken r;
-
-           r = JsonbIteratorNext(&it, &tv, true);
-           container = (JsonbContainer *) jbvp->val.binary.data;
-           have_object = r == WJB_BEGIN_OBJECT;
-           have_array = r == WJB_BEGIN_ARRAY;
+           container = jbvp->val.binary.data;
+           have_object = JsonContainerIsObject(container);
+           have_array = JsonContainerIsArray(container);
+           Assert(!JsonContainerIsScalar(container));
        }
        else
        {
-           have_object = jbvp->type == jbvObject;
-           have_array = jbvp->type == jbvArray;
+           Assert(IsAJsonbScalar(jbvp));
+           have_object = false;
+           have_array = false;
        }
    }
 
    if (as_text)
    {
-       /* special-case outputs for string and null values */
-       if (jbvp->type == jbvString)
-           PG_RETURN_TEXT_P(cstring_to_text_with_len(jbvp->val.string.val,
-                                                     jbvp->val.string.len));
        if (jbvp->type == jbvNull)
            PG_RETURN_NULL();
-   }
-
-   res = JsonbValueToJsonb(jbvp);
 
-   if (as_text)
-   {
-       PG_RETURN_TEXT_P(cstring_to_text(JsonbToCString(NULL,
-                                                       &res->root,
-                                                       VARSIZE(res))));
+       PG_RETURN_TEXT_P(JsonbValueAsText(jbvp));
    }
    else
    {
+       Jsonb      *res = JsonbValueToJsonb(jbvp);
+
        /* not text mode - just hand back the jsonb */
        PG_RETURN_JSONB_P(res);
    }