Improve the efficiency of certain jsonb get operations.

Instead of iterating over jsonb structures, use the inbuilt functions
findJsonbValueFromContainerLen() and getIthJsonbValueFromContainer() to
extract values directly. These functions use algorithms that are O(n log
n) and O(1) respectively, whereas iterating is O(n), so we should see
considerable speedup here.

Teodor Sigaev.

diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c
index b67eb6555c19fb45765a3379e906056b81d5b81b..71179f655182bdfab0e56c215f6660ce79db1b6c 100644 (file)
--- a/src/backend/utils/adt/jsonfuncs.c
+++ b/src/backend/utils/adt/jsonfuncs.c
@@ -466,12 +466,8 @@ Datum
 jsonb_object_field(PG_FUNCTION_ARGS)
 {
    Jsonb      *jb = PG_GETARG_JSONB(0);
-   char       *key = text_to_cstring(PG_GETARG_TEXT_P(1));
-   int         klen = strlen(key);
-   JsonbIterator *it;
-   JsonbValue  v;
-   int         r;
-   bool        skipNested = false;
+   text       *key = PG_GETARG_TEXT_PP(1);
+   JsonbValue *v;
 
    if (JB_ROOT_IS_SCALAR(jb))
        ereport(ERROR,
@@ -484,25 +480,11 @@ jsonb_object_field(PG_FUNCTION_ARGS)
 
    Assert(JB_ROOT_IS_OBJECT(jb));
 
-   it = JsonbIteratorInit(&jb->root);
-
-   while ((r = JsonbIteratorNext(&it, &v, skipNested)) != WJB_DONE)
-   {
-       skipNested = true;
+   v = findJsonbValueFromContainerLen(&jb->root, JB_FOBJECT,
+                                      VARDATA_ANY(key), VARSIZE_ANY_EXHDR(key));
 
-       if (r == WJB_KEY)
-       {
-           if (klen == v.val.string.len && strncmp(key, v.val.string.val, klen) == 0)
-           {
-               /*
-                * The next thing the iterator fetches should be the value, no
-                * matter what shape it is.
-                */
-               (void) JsonbIteratorNext(&it, &v, skipNested);
-               PG_RETURN_JSONB(JsonbValueToJsonb(&v));
-           }
-       }
-   }
+   if (v != NULL)
+       PG_RETURN_JSONB(JsonbValueToJsonb(v));
 
    PG_RETURN_NULL();
 }
@@ -527,12 +509,8 @@ Datum
 jsonb_object_field_text(PG_FUNCTION_ARGS)
 {
    Jsonb      *jb = PG_GETARG_JSONB(0);
-   char       *key = text_to_cstring(PG_GETARG_TEXT_P(1));
-   int         klen = strlen(key);
-   JsonbIterator *it;
-   JsonbValue  v;
-   int         r;
-   bool        skipNested = false;
+   text       *key = PG_GETARG_TEXT_PP(1);
+   JsonbValue *v;
 
    if (JB_ROOT_IS_SCALAR(jb))
        ereport(ERROR,
@@ -545,47 +523,41 @@ jsonb_object_field_text(PG_FUNCTION_ARGS)
 
    Assert(JB_ROOT_IS_OBJECT(jb));
 
-   it = JsonbIteratorInit(&jb->root);
+   v = findJsonbValueFromContainerLen(&jb->root, JB_FOBJECT,
+                                      VARDATA_ANY(key), VARSIZE_ANY_EXHDR(key));
 
-   while ((r = JsonbIteratorNext(&it, &v, skipNested)) != WJB_DONE)
+   if (v != NULL)
    {
-       skipNested = true;
+       text       *result = NULL;
 
-       if (r == WJB_KEY)
+       switch(v->type)
        {
-           if (klen == v.val.string.len && strncmp(key, v.val.string.val, klen) == 0)
-           {
-               text       *result;
-
-               /*
-                * The next thing the iterator fetches should be the value, no
-                * matter what shape it is.
-                */
-               r = JsonbIteratorNext(&it, &v, skipNested);
-
-               /*
-                * if it's a scalar string it needs to be de-escaped,
-                * otherwise just return the text
-                */
-               if (v.type == jbvString)
+           case jbvNull:
+               break;
+           case jbvBool:
+               result = cstring_to_text(v->val.boolean ? "true" : "false");
+               break;
+           case jbvString:
+               result = cstring_to_text_with_len(v->val.string.val, v->val.string.len);
+               break;
+           case jbvNumeric:
+               result = cstring_to_text(DatumGetCString(DirectFunctionCall1(numeric_out,
+                                                                            PointerGetDatum(v->val.numeric))));
+               break;
+           case jbvBinary:
                {
-                   result = cstring_to_text_with_len(v.val.string.val, v.val.string.len);
-               }
-               else if (v.type == jbvNull)
-               {
-                   PG_RETURN_NULL();
-               }
-               else
-               {
-                   StringInfo  jtext = makeStringInfo();
-                   Jsonb      *tjb = JsonbValueToJsonb(&v);
+                   StringInfo  jtext = makeStringInfo();
 
-                   (void) JsonbToCString(jtext, &tjb->root , -1);
+                   (void) JsonbToCString(jtext, v->val.binary.data, -1);
                    result = cstring_to_text_with_len(jtext->data, jtext->len);
                }
-               PG_RETURN_TEXT_P(result);
-           }
+               break;
+           default:
+               elog(ERROR, "Wrong jsonb type: %d", v->type);
        }
+
+       if (result)
+           PG_RETURN_TEXT_P(result);
    }
 
    PG_RETURN_NULL();
@@ -611,11 +583,7 @@ jsonb_array_element(PG_FUNCTION_ARGS)
 {
    Jsonb      *jb = PG_GETARG_JSONB(0);
    int         element = PG_GETARG_INT32(1);
-   JsonbIterator *it;
-   JsonbValue  v;
-   int         r;
-   bool        skipNested = false;
-   int         element_number = 0;
+   JsonbValue *v;
 
    if (JB_ROOT_IS_SCALAR(jb))
        ereport(ERROR,
@@ -628,18 +596,9 @@ jsonb_array_element(PG_FUNCTION_ARGS)
 
    Assert(JB_ROOT_IS_ARRAY(jb));
 
-   it = JsonbIteratorInit(&jb->root);
-
-   while ((r = JsonbIteratorNext(&it, &v, skipNested)) != WJB_DONE)
-   {
-       skipNested = true;
-
-       if (r == WJB_ELEM)
-       {
-           if (element_number++ == element)
-               PG_RETURN_JSONB(JsonbValueToJsonb(&v));
-       }
-   }
+   v = getIthJsonbValueFromContainer(&jb->root, element);
+   if (v != NULL)
+       PG_RETURN_JSONB(JsonbValueToJsonb(v));
 
    PG_RETURN_NULL();
 }
@@ -664,12 +623,7 @@ jsonb_array_element_text(PG_FUNCTION_ARGS)
 {
    Jsonb      *jb = PG_GETARG_JSONB(0);
    int         element = PG_GETARG_INT32(1);
-   JsonbIterator *it;
-   JsonbValue  v;
-   int         r;
-   bool        skipNested = false;
-   int         element_number = 0;
-
+   JsonbValue *v;
 
    if (JB_ROOT_IS_SCALAR(jb))
        ereport(ERROR,
@@ -682,41 +636,39 @@ jsonb_array_element_text(PG_FUNCTION_ARGS)
 
    Assert(JB_ROOT_IS_ARRAY(jb));
 
-   it = JsonbIteratorInit(&jb->root);
-
-   while ((r = JsonbIteratorNext(&it, &v, skipNested)) != WJB_DONE)
+   v = getIthJsonbValueFromContainer(&jb->root, element);
+   if (v != NULL)
    {
-       skipNested = true;
+       text       *result = NULL;
 
-       if (r == WJB_ELEM)
+       switch(v->type)
        {
-           if (element_number++ == element)
-           {
-               /*
-                * if it's a scalar string it needs to be de-escaped,
-                * otherwise just return the text
-                */
-               text       *result;
-
-               if (v.type == jbvString)
-               {
-                   result = cstring_to_text_with_len(v.val.string.val, v.val.string.len);
-               }
-               else if (v.type == jbvNull)
-               {
-                   PG_RETURN_NULL();
-               }
-               else
+           case jbvNull:
+               break;
+           case jbvBool:
+               result = cstring_to_text(v->val.boolean ? "true" : "false");
+               break;
+           case jbvString:
+               result = cstring_to_text_with_len(v->val.string.val, v->val.string.len);
+               break;
+           case jbvNumeric:
+               result = cstring_to_text(DatumGetCString(DirectFunctionCall1(numeric_out,
+                                           PointerGetDatum(v->val.numeric))));
+               break;
+           case jbvBinary:
                {
-                   StringInfo  jtext = makeStringInfo();
-                   Jsonb      *tjb = JsonbValueToJsonb(&v);
+                   StringInfo  jtext = makeStringInfo();
 
-                   (void) JsonbToCString(jtext, &tjb->root, -1);
+                   (void) JsonbToCString(jtext, v->val.binary.data, -1);
                    result = cstring_to_text_with_len(jtext->data, jtext->len);
                }
-               PG_RETURN_TEXT_P(result);
-           }
+               break;
+           default:
+               elog(ERROR, "Wrong jsonb type: %d", v->type);
        }
+
+       if (result)
+           PG_RETURN_TEXT_P(result);
    }
 
    PG_RETURN_NULL();