From fdb88a51cda0ec0e09b986ec68bcea3935424794 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Sat, 19 Sep 2026 20:13:56 +0900 Subject: [PATCH] Fix PASSING of toasted text values in JSON query functions The PASSING arguments of JSON_EXISTS(), JSON_QUERY(), JSON_VALUE() and JSON_TABLE() are evaluated by plain expression steps and given to the jsonpath executor as-is. When dealing with a varlena, JsonItemFromDatum() was building a jbvString directly the contents of a varlena. For a varatt_external (varatt_external[oid/oid8] on HEAD), this ignored that the contents of the varlena need to be detoasted, leading to incorrect contents returned. Let's detoast the value, like the jsonb and json cases. b0feda79fdf0 has fixed the same issue for subscript values in jsonb. Note that the results of DatumGetTextPP() are allocated in the memory context used for the evaluation of the expression, which is reset once per row. Oversight in 6185c9737cf4. Author: Chaitanya Choudhary Author: Shihao Zhong Discussion: https://postgr.es/m/19693-2ecd2b52c838b3e5@postgresql.org Backpatch-through: 17 --- src/backend/utils/adt/jsonpath_exec.c | 12 ++++++--- .../regress/expected/sqljson_queryfuncs.out | 26 +++++++++++++++++++ src/test/regress/sql/sqljson_queryfuncs.sql | 16 ++++++++++++ 3 files changed, 50 insertions(+), 4 deletions(-) diff --git a/src/backend/utils/adt/jsonpath_exec.c b/src/backend/utils/adt/jsonpath_exec.c index 9bf8ecdcd0c..790fbb68194 100644 --- a/src/backend/utils/adt/jsonpath_exec.c +++ b/src/backend/utils/adt/jsonpath_exec.c @@ -3339,10 +3339,14 @@ JsonItemFromDatum(Datum val, Oid typid, int32 typmod, JsonbValue *res) break; case TEXTOID: case VARCHAROID: - res->type = jbvString; - res->val.string.val = VARDATA_ANY(DatumGetPointer(val)); - res->val.string.len = VARSIZE_ANY_EXHDR(DatumGetPointer(val)); - break; + { + text *txt = DatumGetTextPP(val); + + res->type = jbvString; + res->val.string.val = VARDATA_ANY(txt); + res->val.string.len = VARSIZE_ANY_EXHDR(txt); + break; + } case DATEOID: case TIMEOID: case TIMETZOID: diff --git a/src/test/regress/expected/sqljson_queryfuncs.out b/src/test/regress/expected/sqljson_queryfuncs.out index ff64dce0c59..fe8aa927b5e 100644 --- a/src/test/regress/expected/sqljson_queryfuncs.out +++ b/src/test/regress/expected/sqljson_queryfuncs.out @@ -1473,6 +1473,32 @@ SELECT JSON_QUERY(jsonb 'null', '$"Xyz"' PASSING 1 AS "Xyz"); 1 (1 row) +-- Test PASSING and toasted values +CREATE TABLE test_passing_toast (t text); +ALTER TABLE test_passing_toast ALTER COLUMN t SET STORAGE EXTENDED; +INSERT INTO test_passing_toast(t) + SELECT repeat(string_agg(to_char(g.i, 'FM0000'), ''), 50) + FROM generate_series(1, 500) g(i); +ALTER TABLE test_passing_toast ALTER COLUMN t SET STORAGE EXTERNAL; +INSERT INTO test_passing_toast(t) + SELECT repeat(string_agg(to_char(g.i, 'FM0000'), ''), 50) + FROM generate_series(1, 500) g(i); +SELECT count(*) AS toasted_chunks + FROM test_passing_toast WHERE pg_column_toast_chunk_id(t) IS NOT NULL; + toasted_chunks +---------------- + 2 +(1 row) + +SELECT JSON_VALUE(jsonb 'null', '$a' PASSING t AS a) = t AS ok + FROM test_passing_toast; + ok +---- + t + t +(2 rows) + +DROP TABLE test_passing_toast; -- Test ON ERROR / EMPTY value validity for the function; all fail. SELECT JSON_EXISTS(jsonb '1', '$' DEFAULT 1 ON ERROR); ERROR: invalid ON ERROR behavior diff --git a/src/test/regress/sql/sqljson_queryfuncs.sql b/src/test/regress/sql/sqljson_queryfuncs.sql index a69ef253f66..0767db9cfff 100644 --- a/src/test/regress/sql/sqljson_queryfuncs.sql +++ b/src/test/regress/sql/sqljson_queryfuncs.sql @@ -488,6 +488,22 @@ SELECT JSON_QUERY(jsonb 'null', '$Xyz' PASSING 1 AS Xyz); SELECT JSON_QUERY(jsonb 'null', '$Xyz' PASSING 1 AS "Xyz"); SELECT JSON_QUERY(jsonb 'null', '$"Xyz"' PASSING 1 AS "Xyz"); +-- Test PASSING and toasted values +CREATE TABLE test_passing_toast (t text); +ALTER TABLE test_passing_toast ALTER COLUMN t SET STORAGE EXTENDED; +INSERT INTO test_passing_toast(t) + SELECT repeat(string_agg(to_char(g.i, 'FM0000'), ''), 50) + FROM generate_series(1, 500) g(i); +ALTER TABLE test_passing_toast ALTER COLUMN t SET STORAGE EXTERNAL; +INSERT INTO test_passing_toast(t) + SELECT repeat(string_agg(to_char(g.i, 'FM0000'), ''), 50) + FROM generate_series(1, 500) g(i); +SELECT count(*) AS toasted_chunks + FROM test_passing_toast WHERE pg_column_toast_chunk_id(t) IS NOT NULL; +SELECT JSON_VALUE(jsonb 'null', '$a' PASSING t AS a) = t AS ok + FROM test_passing_toast; +DROP TABLE test_passing_toast; + -- Test ON ERROR / EMPTY value validity for the function; all fail. SELECT JSON_EXISTS(jsonb '1', '$' DEFAULT 1 ON ERROR); SELECT JSON_VALUE(jsonb '1', '$' EMPTY ON ERROR);