From 5b891dac2b2781296ab9971a17f8ec0c586ebb1e Mon Sep 17 00:00:00 2001 From: Amit Langote Date: Fri, 30 Aug 2024 12:19:50 +0900 Subject: [PATCH v2 2/4] SQL/JSON: Fix default ON ERROR behavior for JSON_TABLE Use EMPTY ARRAY instead of EMPTY. This change does not affect the runtime behavior of JSON_TABLE(), which continues to return an empty relation ON ERROR. It only alters whether the default ON ERROR behavior is shown in the deparsed output. Reported-by: Jian He Discussion: https://postgr.es/m/CACJufxEo4sUjKCYtda0_qt9tazqqKPmF1cqhW9KBOUeJFqQd2g@mail.gmail.com --- src/backend/parser/parse_expr.c | 4 +-- src/backend/utils/adt/ruleutils.c | 2 +- .../regress/expected/sqljson_jsontable.out | 33 +++++++++++++++++++ src/test/regress/sql/sqljson_jsontable.sql | 6 ++++ 4 files changed, 42 insertions(+), 3 deletions(-) diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index 56e413da9f..36c1b7a88f 100644 --- a/src/backend/parser/parse_expr.c +++ b/src/backend/parser/parse_expr.c @@ -4603,13 +4603,13 @@ transformJsonFuncExpr(ParseState *pstate, JsonFuncExpr *func) } /* - * Assume EMPTY ON ERROR when ON ERROR is not specified. + * Assume EMPTY ARRAY ON ERROR when ON ERROR is not specified. * * ON EMPTY cannot be specified at the top level but it can be for * the individual columns. */ jsexpr->on_error = transformJsonBehavior(pstate, func->on_error, - JSON_BEHAVIOR_EMPTY, + JSON_BEHAVIOR_EMPTY_ARRAY, jsexpr->returning); break; diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c index b31be31321..0aa090be20 100644 --- a/src/backend/utils/adt/ruleutils.c +++ b/src/backend/utils/adt/ruleutils.c @@ -11875,7 +11875,7 @@ get_json_table(TableFunc *tf, deparse_context *context, bool showimplicit) get_json_table_columns(tf, castNode(JsonTablePathScan, tf->plan), context, showimplicit); - if (jexpr->on_error->btype != JSON_BEHAVIOR_EMPTY) + if (jexpr->on_error->btype != JSON_BEHAVIOR_EMPTY_ARRAY) get_json_behavior(jexpr->on_error, context, "ERROR"); if (PRETTY_INDENT(context)) diff --git a/src/test/regress/expected/sqljson_jsontable.out b/src/test/regress/expected/sqljson_jsontable.out index 721e01d6ad..f25d03bc77 100644 --- a/src/test/regress/expected/sqljson_jsontable.out +++ b/src/test/regress/expected/sqljson_jsontable.out @@ -1132,3 +1132,36 @@ ERROR: invalid ON ERROR behavior for column "a" LINE 1: ...M JSON_TABLE(jsonb '1', '$' COLUMNS (a int exists empty obje... ^ DETAIL: Only ERROR, TRUE, FALSE, or UNKNOWN is allowed in ON ERROR for EXISTS columns. +-- Test JSON_TABLE() deparsing -- don't emit default ON ERROR behavior +EXPLAIN VERBOSE SELECT * from JSON_TABLE('"a"', '$' COLUMNS (a text PATH '$')); + QUERY PLAN +----------------------------------------------------------------------------------------------------- + Table Function Scan on "json_table" (cost=0.01..1.00 rows=100 width=32) + Output: a + Table Function Call: JSON_TABLE('"a"'::jsonb, '$' AS json_table_path_0 COLUMNS (a text PATH '$')) +(3 rows) + +EXPLAIN VERBOSE SELECT * from JSON_TABLE('"a"', '$' COLUMNS (a text PATH '$') EMPTY ON ERROR); + QUERY PLAN +----------------------------------------------------------------------------------------------------- + Table Function Scan on "json_table" (cost=0.01..1.00 rows=100 width=32) + Output: a + Table Function Call: JSON_TABLE('"a"'::jsonb, '$' AS json_table_path_0 COLUMNS (a text PATH '$')) +(3 rows) + +EXPLAIN VERBOSE SELECT * from JSON_TABLE('"a"', '$' COLUMNS (a text PATH '$') EMPTY ARRAY ON ERROR); + QUERY PLAN +----------------------------------------------------------------------------------------------------- + Table Function Scan on "json_table" (cost=0.01..1.00 rows=100 width=32) + Output: a + Table Function Call: JSON_TABLE('"a"'::jsonb, '$' AS json_table_path_0 COLUMNS (a text PATH '$')) +(3 rows) + +EXPLAIN VERBOSE SELECT * from JSON_TABLE('"a"', '$' COLUMNS (a text PATH '$') ERROR ON ERROR); + QUERY PLAN +------------------------------------------------------------------------------------------------------------------------------------------------ + Table Function Scan on "json_table" (cost=0.01..1.00 rows=100 width=32) + Output: a + Table Function Call: JSON_TABLE('"a"'::jsonb, '$' AS json_table_path_0 COLUMNS (a text PATH '$' NULL ON EMPTY NULL ON ERROR) ERROR ON ERROR) +(3 rows) + diff --git a/src/test/regress/sql/sqljson_jsontable.sql b/src/test/regress/sql/sqljson_jsontable.sql index 38992316f5..932a3ecf59 100644 --- a/src/test/regress/sql/sqljson_jsontable.sql +++ b/src/test/regress/sql/sqljson_jsontable.sql @@ -542,3 +542,9 @@ SELECT * FROM JSON_TABLE(jsonb '1', '$' COLUMNS (a int) NULL ON ERROR); SELECT * FROM JSON_TABLE(jsonb '1', '$' COLUMNS (a int true on empty)); SELECT * FROM JSON_TABLE(jsonb '1', '$' COLUMNS (a int omit quotes true on error)); SELECT * FROM JSON_TABLE(jsonb '1', '$' COLUMNS (a int exists empty object on error)); + +-- Test JSON_TABLE() deparsing -- don't emit default ON ERROR behavior +EXPLAIN VERBOSE SELECT * from JSON_TABLE('"a"', '$' COLUMNS (a text PATH '$')); +EXPLAIN VERBOSE SELECT * from JSON_TABLE('"a"', '$' COLUMNS (a text PATH '$') EMPTY ON ERROR); +EXPLAIN VERBOSE SELECT * from JSON_TABLE('"a"', '$' COLUMNS (a text PATH '$') EMPTY ARRAY ON ERROR); +EXPLAIN VERBOSE SELECT * from JSON_TABLE('"a"', '$' COLUMNS (a text PATH '$') ERROR ON ERROR); -- 2.43.0