postgres.git / summary / log / commit / refs
commit c88ce386c4d7bfeb437ff31ec7c23c392c862e77
Author: Amit Langote <amitlan@postgresql.org>
Date: Fri Sep 06 01:12:16 2024 +0000
First released in: master (reverted before release), REL_17_STABLE (reverted before release)
Reverted by: eef5195f300b (in 17.0), 4d7e24e0f4d0 (in 18.0)
SQL/JSON: Fix JSON_TABLE() column deparsing
The deparsing code in get_json_expr_options() unnecessarily emitted
the default column-specific ON ERROR / EMPTY behavior when the
top-level ON ERROR behavior in JSON_TABLE was set to ERROR. Fix that
by not overriding the column-specific default, determined based on
the column's JsonExprOp in get_json_table_columns(), with
JSON_BEHAVIOR_ERROR when that is the top-level ON ERROR behavior.
Note that this only removes redundancy; the current deparsing output
is not incorrect, just redundant.
Reviewed-by: Jian He <jian.universality@gmail.com>
Discussion: https://postgr.es/m/CACJufxEo4sUjKCYtda0_qt9tazqqKPmF1cqhW9KBOUeJFqQd2g@mail.gmail.com
Backpatch-through: 17
src/backend/utils/adt/ruleutils.c | 8 ++++----
src/test/regress/expected/sqljson_jsontable.out | 18 ++++++++++++++++++
src/test/regress/sql/sqljson_jsontable.sql | 5 +++++
3 files changed, 27 insertions(+), 4 deletions(-)
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index b31be31321d..371b46e7a2d 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -11719,7 +11719,6 @@ get_json_table_columns(TableFunc *tf, JsonTablePathScan *scan,
bool showimplicit)
{
StringInfo buf = context->buf;
- JsonExpr *jexpr = castNode(JsonExpr, tf->docexpr);
ListCell *lc_colname;
ListCell *lc_coltype;
ListCell *lc_coltypmod;
@@ -11772,6 +11771,10 @@ get_json_table_columns(TableFunc *tf, JsonTablePathScan *scan,
if (ordinality)
continue;
+ /*
+ * Set default_behavior to guide get_json_expr_options() on whether to
+ * to emit the ON ERROR / EMPTY clauses.
+ */
if (colexpr->op == JSON_EXISTS_OP)
{
appendStringInfoString(buf, " EXISTS");
@@ -11795,9 +11798,6 @@ get_json_table_columns(TableFunc *tf, JsonTablePathScan *scan,
default_behavior = JSON_BEHAVIOR_NULL;
}
- if (jexpr->on_error->btype == JSON_BEHAVIOR_ERROR)
- default_behavior = JSON_BEHAVIOR_ERROR;
-
appendStringInfoString(buf, " PATH ");
get_json_path_spec(colexpr->path_spec, context, showimplicit);
diff --git a/src/test/regress/expected/sqljson_jsontable.out b/src/test/regress/expected/sqljson_jsontable.out
index 721e01d6ad0..ebfde38a056 100644
--- a/src/test/regress/expected/sqljson_jsontable.out
+++ b/src/test/regress/expected/sqljson_jsontable.out
@@ -1132,3 +1132,21 @@ ERROR: invalid ON ERROR behavior for column "a"
LINE 1: ...M JSON_TABLE(jsonb '1', '$' COLUMNS (a int exists empty obje...
^
DETAIL: Only ERROR, TRUE, FALSE, or UNKNOWN is allowed in ON ERROR for EXISTS columns.
+-- Test JSON_TABLE() column deparsing -- don't emit default ON ERROR / EMPTY
+-- behavior
+EXPLAIN VERBOSE SELECT * from JSON_TABLE('"a"', '$' 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 '$') ERROR ON ERROR);
+ QUERY PLAN
+--------------------------------------------------------------------------------------------------------------------
+ Table Function Scan on "json_table" (cost=0.01..1.00 rows=100 width=32)
+ Output: a
+ Table Function Call: JSON_TABLE('"a"'::jsonb, '$' AS json_table_path_0 COLUMNS (a text PATH '$') ERROR ON ERROR)
+(3 rows)
+
diff --git a/src/test/regress/sql/sqljson_jsontable.sql b/src/test/regress/sql/sqljson_jsontable.sql
index 38992316f5a..c9408878926 100644
--- a/src/test/regress/sql/sqljson_jsontable.sql
+++ b/src/test/regress/sql/sqljson_jsontable.sql
@@ -542,3 +542,8 @@ SELECT * FROM JSON_TABLE(jsonb '1', '$' 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', '$' COLUMNS (a int exists empty object on error));
+
+-- Test JSON_TABLE() column deparsing -- don't emit default ON ERROR / EMPTY
+-- behavior
+EXPLAIN VERBOSE SELECT * from JSON_TABLE('"a"', '$' COLUMNS (a text PATH '$'));
+EXPLAIN VERBOSE SELECT * from JSON_TABLE('"a"', '$' COLUMNS (a text PATH '$') ERROR ON ERROR);
[parent: fe323438140f]