From af88d7dcbf18ed9041dc94a22a3cdfc92ad9c789 Mon Sep 17 00:00:00 2001 From: Dmitrii Dolgov <9erthalion6@gmail.com> Date: Thu, 19 Dec 2019 14:13:35 +0100 Subject: [PATCH v29 6/6] Filling gaps in jsonb arrays Appending or prepending array elements on the specified position, gaps filled with nulls (JavaScript has similar behavior) Author: Nikita Glukhov --- src/backend/utils/adt/jsonfuncs.c | 26 +++++++++++- src/test/regress/expected/jsonb.out | 62 ++++++++++++++--------------- 2 files changed, 55 insertions(+), 33 deletions(-) diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c index a5120d005e..2bc13f9e5d 100644 --- a/src/backend/utils/adt/jsonfuncs.c +++ b/src/backend/utils/adt/jsonfuncs.c @@ -1620,6 +1620,17 @@ jsonb_subscript_apply(JsonbValue *jbv, Datum subscriptVal, Oid subscriptTypid, } } +static void +push_null_elements(JsonbParseState **ps, int num) +{ + JsonbValue null; + + null.type = jbvNull; + + while (num-- > 0) + pushJsonbValue(ps, WJB_ELEM, &null); +} + /* Perfrom one subscript assignment step */ static void jsonb_subscript_step_assignment(SubscriptingRefState *sbstate, Datum value, @@ -1676,6 +1687,10 @@ jsonb_subscript_step_assignment(SubscriptingRefState *sbstate, Datum value, JsonbIteratorNext(&astate->iter, &jbv, last) != WJB_END_ARRAY) subscript[1].exists = true; } + + /* Fill the gap before the new element with nulls */ + if (i < index) + push_null_elements(&astate->ps, index - i); } else { @@ -5318,8 +5333,15 @@ jsonb_subscript_assign(Datum containerSource, SubscriptingRefState *sbstate) if (subscript[1].exists) break; - if (subscript->is_array && subscript->array_index < 0 && subscript->exists) - break; /* original elements are copied from the iterator */ + if (subscript->is_array && subscript->array_index < 0) + { + /* Fill the gap between prepended element and 0th element */ + if (subscript->array_index < -1) + push_null_elements(&astate->ps, -1 - subscript->array_index); + + if (subscript->exists) + break; /* original elements are copied from the iterator */ + } tok = subscript->is_array ? WJB_END_ARRAY : WJB_END_OBJECT; res = pushJsonbValue(&astate->ps, tok, NULL); diff --git a/src/test/regress/expected/jsonb.out b/src/test/regress/expected/jsonb.out index 8b403aa2a2..526fb7574b 100644 --- a/src/test/regress/expected/jsonb.out +++ b/src/test/regress/expected/jsonb.out @@ -4967,35 +4967,35 @@ select * from test_jsonb_subscript; -- append element to array with a gap filled with nulls update test_jsonb_subscript set test_json['a'][7] = '8'::jsonb; select * from test_jsonb_subscript; - id | test_json -----+------------------------------------------ - 1 | {"a": [1, 2, 3, "4", 8]} - 2 | {"a": [1, 2, 3, "4", 8], "key": "value"} + id | test_json +----+------------------------------------------------------------ + 1 | {"a": [1, 2, 3, "4", null, null, null, 8]} + 2 | {"a": [1, 2, 3, "4", null, null, null, 8], "key": "value"} (2 rows) -- replace element in array using negative subscript update test_jsonb_subscript set test_json['a'][-4] = '5'::jsonb; select * from test_jsonb_subscript; - id | test_json -----+------------------------------------------ - 1 | {"a": [1, 5, 3, "4", 8]} - 2 | {"a": [1, 5, 3, "4", 8], "key": "value"} + id | test_json +----+--------------------------------------------------------- + 1 | {"a": [1, 2, 3, "4", 5, null, null, 8]} + 2 | {"a": [1, 2, 3, "4", 5, null, null, 8], "key": "value"} (2 rows) -- prepend element to array using negative subscript with a gap filled with nulls update test_jsonb_subscript set test_json['a'][-10] = '6'::jsonb; select * from test_jsonb_subscript; - id | test_json -----+--------------------------------------------- - 1 | {"a": [6, 1, 5, 3, "4", 8]} - 2 | {"a": [6, 1, 5, 3, "4", 8], "key": "value"} + id | test_json +----+------------------------------------------------------------------ + 1 | {"a": [6, null, 1, 2, 3, "4", 5, null, null, 8]} + 2 | {"a": [6, null, 1, 2, 3, "4", 5, null, null, 8], "key": "value"} (2 rows) -- use jsonb subscription in where clause select * from test_jsonb_subscript where test_json['key'] = '"value"'; - id | test_json -----+--------------------------------------------- - 2 | {"a": [6, 1, 5, 3, "4", 8], "key": "value"} + id | test_json +----+------------------------------------------------------------------ + 2 | {"a": [6, null, 1, 2, 3, "4", 5, null, null, 8], "key": "value"} (1 row) select * from test_jsonb_subscript where test_json['key_doesnt_exists'] = '"value"'; @@ -5013,10 +5013,10 @@ update test_jsonb_subscript set test_json[NULL] = 1; ERROR: subscript in assignment must not be null update test_jsonb_subscript set test_json['another_key'] = NULL; select * from test_jsonb_subscript; - id | test_json -----+------------------------------------------------------------------ - 1 | {"a": [6, 1, 5, 3, "4", 8], "another_key": null} - 2 | {"a": [6, 1, 5, 3, "4", 8], "key": "value", "another_key": null} + id | test_json +----+--------------------------------------------------------------------------------------- + 1 | {"a": [6, null, 1, 2, 3, "4", 5, null, null, 8], "another_key": null} + 2 | {"a": [6, null, 1, 2, 3, "4", 5, null, null, 8], "key": "value", "another_key": null} (2 rows) -- create a path @@ -5045,30 +5045,30 @@ select * from test_jsonb_subscript; update test_jsonb_subscript set test_json['d'][0]['a'][3] = '4'::jsonb; select * from test_jsonb_subscript; - id | test_json -----+-------------------------------------------------------- - 0 | {"a": 1, "b": [2], "c": [{"a": 3}], "d": [{"a": [4]}]} + id | test_json +----+-------------------------------------------------------------------------- + 0 | {"a": 1, "b": [2], "c": [{"a": 3}], "d": [{"a": [null, null, null, 4]}]} (1 row) update test_jsonb_subscript set test_json['d'][0]['c'][-3] = '5'::jsonb; select * from test_jsonb_subscript; - id | test_json -----+------------------------------------------------------------------ - 0 | {"a": 1, "b": [2], "c": [{"a": 3}], "d": [{"a": [4], "c": [5]}]} + id | test_json +----+------------------------------------------------------------------------------------------------ + 0 | {"a": 1, "b": [2], "c": [{"a": 3}], "d": [{"a": [null, null, null, 4], "c": [5, null, null]}]} (1 row) update test_jsonb_subscript set test_json['d'][0]['b']['x'] = '6'::jsonb; select * from test_jsonb_subscript; - id | test_json -----+--------------------------------------------------------------------------------- - 0 | {"a": 1, "b": [2], "c": [{"a": 3}], "d": [{"a": [4], "b": {"x": 6}, "c": [5]}]} + id | test_json +----+--------------------------------------------------------------------------------------------------------------- + 0 | {"a": 1, "b": [2], "c": [{"a": 3}], "d": [{"a": [null, null, null, 4], "b": {"x": 6}, "c": [5, null, null]}]} (1 row) update test_jsonb_subscript set test_json['e']['y'] = '7'::jsonb; select * from test_jsonb_subscript; - id | test_json -----+------------------------------------------------------------------------------------------------ - 0 | {"a": 1, "b": [2], "c": [{"a": 3}], "d": [{"a": [4], "b": {"x": 6}, "c": [5]}], "e": {"y": 7}} + id | test_json +----+------------------------------------------------------------------------------------------------------------------------------ + 0 | {"a": 1, "b": [2], "c": [{"a": 3}], "d": [{"a": [null, null, null, 4], "b": {"x": 6}, "c": [5, null, null]}], "e": {"y": 7}} (1 row) -- updating of scalar's subscripts -- 2.21.0