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help / color / mirror / Atom feedFrom: Matheus Alcantara <[email protected]>
To: Yugo Nagata <[email protected]>
Cc: Peter Eisentraut <[email protected]>
Cc: [email protected]
Subject: Re: Show expression of virtual columns in error messages
Date: Thu, 05 Feb 2026 15:51:54 -0300
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
<[email protected]>
<[email protected]>
<[email protected]>
On Wed Feb 4, 2026 at 11:45 PM -03, Yugo Nagata wrote:
>> Another possibility would be to get the actual values of "a" for example
>> and show it on the error message, e.g:
>>
>> ERROR: new row for relation "t" violates check constraint "t_c_check"
>> DETAIL: Failing row contains (5, 10, 5 * 2).
>
> That would indeed be more useful. One way to achieve this might be to
> modify deparse_context and get_variable() so that a Var is displayed as its
> actual value.
>
I'm not sure if I understand how modifying deparse_context_for() could
help on this.
What I did was to use the expression_tree_mutator API to mutate the
virtual column expression to replace any Var reference with the value
into the TupleTableSlot. Please see the attached v2 version.
> Another possibility would be to include column names in the DETAIL message,
> for example:
>
> ERROR: new row for relation "t" violates check constraint "t_c_check"
> DETAIL: Failing row contains (a, b, c)=(5, 10, a * 2).
>
> Although this would change the existing message format, including column
> names could generally provide users with more information about the error.
>
I think that this could make the error output too verbose when there is
a lot of columns involved on the statement.
--
Matheus Alcantara
EDB: https://www.enterprisedb.com
From 76b5b36ba3b103e7c501de0bd94e9bb1afcdcf75 Mon Sep 17 00:00:00 2001
From: Matheus Alcantara <[email protected]>
Date: Mon, 2 Feb 2026 19:06:44 -0300
Subject: [PATCH v2] Show expression of virtual columns in error messages
Previously, when a constraint violation occurred on a table with virtual
generated columns, the "Failing row contains" error message would display
the literal string "virtual" as a placeholder for those columns. This was
not helpful for debugging.
Now, the generation expression is shown instead, making it easier to
understand what value would be computed for the virtual column.
For example, instead of:
Failing row contains (5, 10, virtual).
The error message now shows:
Failing row contains (5, 10, a * 2).
This required changing ExecBuildSlotValueDescription() to accept a
Relation instead of just an Oid, so that build_generation_expression()
can be called to retrieve the column's generation expression.
---
src/backend/executor/execMain.c | 97 ++++++++++++++++---
src/backend/replication/logical/conflict.c | 7 +-
src/include/executor/executor.h | 2 +-
.../regress/expected/generated_virtual.out | 18 ++--
src/test/regress/expected/partition_merge.out | 2 +-
src/tools/pgindent/typedefs.list | 1 +
6 files changed, 101 insertions(+), 26 deletions(-)
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index bfd3ebc601e..b82c500ba90 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -51,6 +51,8 @@
#include "foreign/fdwapi.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
+#include "nodes/makefuncs.h"
+#include "nodes/nodeFuncs.h"
#include "nodes/queryjumble.h"
#include "parser/parse_relation.h"
#include "pgstat.h"
@@ -61,8 +63,18 @@
#include "utils/lsyscache.h"
#include "utils/partcache.h"
#include "utils/rls.h"
+#include "utils/ruleutils.h"
#include "utils/snapmgr.h"
+/*
+ * Context for substitute_actual_values_mutator
+ */
+typedef struct
+{
+ TupleTableSlot *slot;
+ TupleDesc tupdesc;
+} substitute_actual_values_context;
+
/* Hooks for plugins to get control in ExecutorStart/Run/Finish/End */
ExecutorStart_hook_type ExecutorStart_hook = NULL;
@@ -93,6 +105,9 @@ static void ReportNotNullViolationError(ResultRelInfo *resultRelInfo,
TupleTableSlot *slot,
EState *estate, int attnum);
+static Node *substitute_actual_values_mutator(Node *node,
+ substitute_actual_values_context *context);
+
/* end of local decls */
@@ -1914,7 +1929,7 @@ ExecPartitionCheckEmitError(ResultRelInfo *resultRelInfo,
TupleTableSlot *slot,
EState *estate)
{
- Oid root_relid;
+ Relation root_rel;
TupleDesc tupdesc;
char *val_desc;
Bitmapset *modifiedCols;
@@ -1931,8 +1946,8 @@ ExecPartitionCheckEmitError(ResultRelInfo *resultRelInfo,
TupleDesc old_tupdesc;
AttrMap *map;
- root_relid = RelationGetRelid(rootrel->ri_RelationDesc);
- tupdesc = RelationGetDescr(rootrel->ri_RelationDesc);
+ root_rel = rootrel->ri_RelationDesc;
+ tupdesc = RelationGetDescr(root_rel);
old_tupdesc = RelationGetDescr(resultRelInfo->ri_RelationDesc);
/* a reverse map */
@@ -1950,13 +1965,13 @@ ExecPartitionCheckEmitError(ResultRelInfo *resultRelInfo,
}
else
{
- root_relid = RelationGetRelid(resultRelInfo->ri_RelationDesc);
- tupdesc = RelationGetDescr(resultRelInfo->ri_RelationDesc);
+ root_rel = resultRelInfo->ri_RelationDesc;
+ tupdesc = RelationGetDescr(root_rel);
modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate),
ExecGetUpdatedCols(resultRelInfo, estate));
}
- val_desc = ExecBuildSlotValueDescription(root_relid,
+ val_desc = ExecBuildSlotValueDescription(root_rel,
slot,
tupdesc,
modifiedCols,
@@ -2068,7 +2083,7 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
else
modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate),
ExecGetUpdatedCols(resultRelInfo, estate));
- val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
+ val_desc = ExecBuildSlotValueDescription(rel,
slot,
tupdesc,
modifiedCols,
@@ -2205,7 +2220,7 @@ ReportNotNullViolationError(ResultRelInfo *resultRelInfo, TupleTableSlot *slot,
modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate),
ExecGetUpdatedCols(resultRelInfo, estate));
- val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
+ val_desc = ExecBuildSlotValueDescription(rel,
slot,
tupdesc,
modifiedCols,
@@ -2313,7 +2328,7 @@ ExecWithCheckOptions(WCOKind kind, ResultRelInfo *resultRelInfo,
else
modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate),
ExecGetUpdatedCols(resultRelInfo, estate));
- val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
+ val_desc = ExecBuildSlotValueDescription(rel,
slot,
tupdesc,
modifiedCols,
@@ -2392,12 +2407,13 @@ ExecWithCheckOptions(WCOKind kind, ResultRelInfo *resultRelInfo,
* columns they are.
*/
char *
-ExecBuildSlotValueDescription(Oid reloid,
+ExecBuildSlotValueDescription(Relation rel,
TupleTableSlot *slot,
TupleDesc tupdesc,
Bitmapset *modifiedCols,
int maxfieldlen)
{
+ Oid reloid = RelationGetRelid(rel);
StringInfoData buf;
StringInfoData collist;
bool write_comma = false;
@@ -2477,7 +2493,23 @@ ExecBuildSlotValueDescription(Oid reloid,
if (table_perm || column_perm)
{
if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
- val = "virtual";
+ {
+ Node *genexpr = build_generation_expression(rel, att->attnum);
+ substitute_actual_values_context cxt;
+ List *dpcontext;
+
+ cxt.slot = slot;
+ cxt.tupdesc = tupdesc;
+ genexpr = substitute_actual_values_mutator(genexpr, &cxt);
+
+ /*
+ * We need dpcontext for any remaining Vars that weren't
+ * substituted (e.g system columns).
+ */
+ dpcontext = deparse_context_for(RelationGetRelationName(rel), reloid);
+
+ val = deparse_expression(genexpr, dpcontext, false, false);
+ }
else if (slot->tts_isnull[i])
val = "null";
else
@@ -3241,3 +3273,46 @@ EvalPlanQualEnd(EPQState *epqstate)
epqstate->relsubs_done = NULL;
epqstate->relsubs_blocked = NULL;
}
+
+/*
+ * Replaces Var nodes with Const nodes containing the actual values from the
+ * tuple slot.
+ *
+ * This is used to display the actual values used in virtual generated column
+ * expressions for error messages.
+ */
+static Node *
+substitute_actual_values_mutator(Node *node,
+ substitute_actual_values_context *context)
+{
+ if (node == NULL)
+ return NULL;
+
+ if (IsA(node, Var))
+ {
+ Var *var = (Var *) node;
+ int attnum = var->varattno;
+
+ if (attnum > 0 && attnum <= context->tupdesc->natts)
+ {
+ Form_pg_attribute att = TupleDescAttr(context->tupdesc, attnum - 1);
+ Datum value;
+ bool isnull;
+
+ value = context->slot->tts_values[attnum - 1];
+ isnull = context->slot->tts_isnull[attnum - 1];
+
+ return (Node *) makeConst(att->atttypid,
+ att->atttypmod,
+ att->attcollation,
+ att->attlen,
+ value,
+ isnull,
+ att->attbyval);
+ }
+ }
+
+ return expression_tree_mutator(node,
+ substitute_actual_values_mutator,
+ context);
+}
diff --git a/src/backend/replication/logical/conflict.c b/src/backend/replication/logical/conflict.c
index ca71a81c7bf..478c0a223fc 100644
--- a/src/backend/replication/logical/conflict.c
+++ b/src/backend/replication/logical/conflict.c
@@ -432,7 +432,6 @@ get_tuple_desc(EState *estate, ResultRelInfo *relinfo, ConflictType type,
Oid indexoid)
{
Relation localrel = relinfo->ri_RelationDesc;
- Oid relid = RelationGetRelid(localrel);
TupleDesc tupdesc = RelationGetDescr(localrel);
char *desc = NULL;
@@ -461,7 +460,7 @@ get_tuple_desc(EState *estate, ResultRelInfo *relinfo, ConflictType type,
* The 'modifiedCols' only applies to the new tuple, hence we pass
* NULL for the local row.
*/
- desc = ExecBuildSlotValueDescription(relid, localslot, tupdesc,
+ desc = ExecBuildSlotValueDescription(localrel, localslot, tupdesc,
NULL, 64);
if (desc)
@@ -481,7 +480,7 @@ get_tuple_desc(EState *estate, ResultRelInfo *relinfo, ConflictType type,
*/
modifiedCols = bms_union(ExecGetInsertedCols(relinfo, estate),
ExecGetUpdatedCols(relinfo, estate));
- desc = ExecBuildSlotValueDescription(relid, remoteslot,
+ desc = ExecBuildSlotValueDescription(localrel, remoteslot,
tupdesc, modifiedCols,
64);
@@ -510,7 +509,7 @@ get_tuple_desc(EState *estate, ResultRelInfo *relinfo, ConflictType type,
if (OidIsValid(replica_index))
desc = build_index_value_desc(estate, localrel, searchslot, replica_index);
else
- desc = ExecBuildSlotValueDescription(relid, searchslot, tupdesc, NULL, 64);
+ desc = ExecBuildSlotValueDescription(localrel, searchslot, tupdesc, NULL, 64);
if (desc)
{
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 55a7d930d26..2ffb97d48ca 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -269,7 +269,7 @@ extern void ExecPartitionCheckEmitError(ResultRelInfo *resultRelInfo,
TupleTableSlot *slot, EState *estate);
extern void ExecWithCheckOptions(WCOKind kind, ResultRelInfo *resultRelInfo,
TupleTableSlot *slot, EState *estate);
-extern char *ExecBuildSlotValueDescription(Oid reloid, TupleTableSlot *slot,
+extern char *ExecBuildSlotValueDescription(Relation rel, TupleTableSlot *slot,
TupleDesc tupdesc,
Bitmapset *modifiedCols,
int maxfieldlen);
diff --git a/src/test/regress/expected/generated_virtual.out b/src/test/regress/expected/generated_virtual.out
index 249e68be654..a55470fd47f 100644
--- a/src/test/regress/expected/generated_virtual.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -638,7 +638,7 @@ CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTU
INSERT INTO gtest20 (a) VALUES (10); -- ok
INSERT INTO gtest20 (a) VALUES (30); -- violates constraint
ERROR: new row for relation "gtest20" violates check constraint "gtest20_b_check"
-DETAIL: Failing row contains (30, virtual).
+DETAIL: Failing row contains (30, (30 * 2)).
ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100); -- violates constraint (currently not supported)
ERROR: ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns in tables with check constraints
DETAIL: Column "b" of relation "gtest20" is a virtual generated column.
@@ -666,18 +666,18 @@ ALTER TABLE gtest20c ADD CONSTRAINT whole_row_check CHECK (gtest20c IS NOT NULL)
INSERT INTO gtest20c VALUES (1); -- ok
INSERT INTO gtest20c VALUES (NULL); -- fails
ERROR: new row for relation "gtest20c" violates check constraint "whole_row_check"
-DETAIL: Failing row contains (null, virtual).
+DETAIL: Failing row contains (null, (NULL::integer * 2)).
-- not-null constraints
CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
INSERT INTO gtest21a (a) VALUES (1); -- ok
INSERT INTO gtest21a (a) VALUES (0); -- violates constraint
ERROR: null value in column "b" of relation "gtest21a" violates not-null constraint
-DETAIL: Failing row contains (0, virtual).
+DETAIL: Failing row contains (0, NULLIF(0, 0)).
-- also check with table constraint syntax
CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL, CONSTRAINT cc NOT NULL b);
INSERT INTO gtest21ax (a) VALUES (0); -- violates constraint
ERROR: null value in column "b" of relation "gtest21ax" violates not-null constraint
-DETAIL: Failing row contains (0, virtual).
+DETAIL: Failing row contains (0, NULLIF(0, 0)).
INSERT INTO gtest21ax (a) VALUES (1); --ok
-- SET EXPRESSION supports not null constraint
ALTER TABLE gtest21ax ALTER COLUMN b SET EXPRESSION AS (nullif(a, 1)); --error
@@ -687,17 +687,17 @@ CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a,
ALTER TABLE gtest21ax ADD CONSTRAINT cc NOT NULL b;
INSERT INTO gtest21ax (a) VALUES (0); -- violates constraint
ERROR: null value in column "b" of relation "gtest21ax" violates not-null constraint
-DETAIL: Failing row contains (0, virtual).
+DETAIL: Failing row contains (0, NULLIF(0, 0)).
DROP TABLE gtest21ax;
CREATE TABLE gtest21b (a int, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
INSERT INTO gtest21b (a) VALUES (1); -- ok
INSERT INTO gtest21b (a) VALUES (2), (0); -- violates constraint
ERROR: null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL: Failing row contains (0, virtual).
+DETAIL: Failing row contains (0, NULLIF(0, 0)).
INSERT INTO gtest21b (a) VALUES (NULL); -- error
ERROR: null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL: Failing row contains (null, virtual).
+DETAIL: Failing row contains (null, NULLIF(NULL::integer, 0)).
ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
INSERT INTO gtest21b (a) VALUES (0); -- ok now
-- not-null constraint with partitioned table
@@ -712,10 +712,10 @@ CREATE TABLE gtestnn_childdef PARTITION OF gtestnn_parent default;
INSERT INTO gtestnn_parent VALUES (2, 2, default), (3, 5, default), (14, 12, default); -- ok
INSERT INTO gtestnn_parent VALUES (1, 2, default); -- error
ERROR: null value in column "f3" of relation "gtestnn_child" violates not-null constraint
-DETAIL: Failing row contains (1, 2, virtual).
+DETAIL: Failing row contains (1, 2, (NULLIF(1, 1) + NULLIF('2'::bigint, 10))).
INSERT INTO gtestnn_parent VALUES (2, 10, default); -- error
ERROR: null value in column "f3" of relation "gtestnn_child" violates not-null constraint
-DETAIL: Failing row contains (2, 10, virtual).
+DETAIL: Failing row contains (2, 10, (NULLIF(2, 1) + NULLIF('10'::bigint, 10))).
ALTER TABLE gtestnn_parent ALTER COLUMN f3 SET EXPRESSION AS (nullif(f1, 2) + nullif(f2, 11)); -- error
ERROR: column "f3" of relation "gtestnn_child" contains null values
INSERT INTO gtestnn_parent VALUES (10, 11, default); -- ok
diff --git a/src/test/regress/expected/partition_merge.out b/src/test/regress/expected/partition_merge.out
index 925fe4f570a..ae40cb9cfcb 100644
--- a/src/test/regress/expected/partition_merge.out
+++ b/src/test/regress/expected/partition_merge.out
@@ -1073,7 +1073,7 @@ INSERT INTO t VALUES (16);
-- ERROR: new row for relation "tp_12" violates check constraint "t_i_check"
INSERT INTO t VALUES (0);
ERROR: new row for relation "tp_12" violates check constraint "t_i_check"
-DETAIL: Failing row contains (0, virtual).
+DETAIL: Failing row contains (0, (0 + (tableoid)::integer)).
-- Should be 3 rows: (5), (15), (16):
SELECT i FROM t ORDER BY i;
i
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 9f5ee8fd482..0bc6f86b884 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2950,6 +2950,7 @@ SubscriptingRefState
Subscription
SubscriptionInfo
SubscriptionRelState
+substitute_actual_values_context
SummarizerReadLocalXLogPrivate
SupportRequestCost
SupportRequestIndexCondition
--
2.52.0
Attachments:
[text/plain] v2-0001-Show-expression-of-virtual-columns-in-error-messa.patch (15.2K, ../[email protected]/2-v2-0001-Show-expression-of-virtual-columns-in-error-messa.patch)
download | inline diff:
From 76b5b36ba3b103e7c501de0bd94e9bb1afcdcf75 Mon Sep 17 00:00:00 2001
From: Matheus Alcantara <[email protected]>
Date: Mon, 2 Feb 2026 19:06:44 -0300
Subject: [PATCH v2] Show expression of virtual columns in error messages
Previously, when a constraint violation occurred on a table with virtual
generated columns, the "Failing row contains" error message would display
the literal string "virtual" as a placeholder for those columns. This was
not helpful for debugging.
Now, the generation expression is shown instead, making it easier to
understand what value would be computed for the virtual column.
For example, instead of:
Failing row contains (5, 10, virtual).
The error message now shows:
Failing row contains (5, 10, a * 2).
This required changing ExecBuildSlotValueDescription() to accept a
Relation instead of just an Oid, so that build_generation_expression()
can be called to retrieve the column's generation expression.
---
src/backend/executor/execMain.c | 97 ++++++++++++++++---
src/backend/replication/logical/conflict.c | 7 +-
src/include/executor/executor.h | 2 +-
.../regress/expected/generated_virtual.out | 18 ++--
src/test/regress/expected/partition_merge.out | 2 +-
src/tools/pgindent/typedefs.list | 1 +
6 files changed, 101 insertions(+), 26 deletions(-)
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index bfd3ebc601e..b82c500ba90 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -51,6 +51,8 @@
#include "foreign/fdwapi.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
+#include "nodes/makefuncs.h"
+#include "nodes/nodeFuncs.h"
#include "nodes/queryjumble.h"
#include "parser/parse_relation.h"
#include "pgstat.h"
@@ -61,8 +63,18 @@
#include "utils/lsyscache.h"
#include "utils/partcache.h"
#include "utils/rls.h"
+#include "utils/ruleutils.h"
#include "utils/snapmgr.h"
+/*
+ * Context for substitute_actual_values_mutator
+ */
+typedef struct
+{
+ TupleTableSlot *slot;
+ TupleDesc tupdesc;
+} substitute_actual_values_context;
+
/* Hooks for plugins to get control in ExecutorStart/Run/Finish/End */
ExecutorStart_hook_type ExecutorStart_hook = NULL;
@@ -93,6 +105,9 @@ static void ReportNotNullViolationError(ResultRelInfo *resultRelInfo,
TupleTableSlot *slot,
EState *estate, int attnum);
+static Node *substitute_actual_values_mutator(Node *node,
+ substitute_actual_values_context *context);
+
/* end of local decls */
@@ -1914,7 +1929,7 @@ ExecPartitionCheckEmitError(ResultRelInfo *resultRelInfo,
TupleTableSlot *slot,
EState *estate)
{
- Oid root_relid;
+ Relation root_rel;
TupleDesc tupdesc;
char *val_desc;
Bitmapset *modifiedCols;
@@ -1931,8 +1946,8 @@ ExecPartitionCheckEmitError(ResultRelInfo *resultRelInfo,
TupleDesc old_tupdesc;
AttrMap *map;
- root_relid = RelationGetRelid(rootrel->ri_RelationDesc);
- tupdesc = RelationGetDescr(rootrel->ri_RelationDesc);
+ root_rel = rootrel->ri_RelationDesc;
+ tupdesc = RelationGetDescr(root_rel);
old_tupdesc = RelationGetDescr(resultRelInfo->ri_RelationDesc);
/* a reverse map */
@@ -1950,13 +1965,13 @@ ExecPartitionCheckEmitError(ResultRelInfo *resultRelInfo,
}
else
{
- root_relid = RelationGetRelid(resultRelInfo->ri_RelationDesc);
- tupdesc = RelationGetDescr(resultRelInfo->ri_RelationDesc);
+ root_rel = resultRelInfo->ri_RelationDesc;
+ tupdesc = RelationGetDescr(root_rel);
modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate),
ExecGetUpdatedCols(resultRelInfo, estate));
}
- val_desc = ExecBuildSlotValueDescription(root_relid,
+ val_desc = ExecBuildSlotValueDescription(root_rel,
slot,
tupdesc,
modifiedCols,
@@ -2068,7 +2083,7 @@ ExecConstraints(ResultRelInfo *resultRelInfo,
else
modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate),
ExecGetUpdatedCols(resultRelInfo, estate));
- val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
+ val_desc = ExecBuildSlotValueDescription(rel,
slot,
tupdesc,
modifiedCols,
@@ -2205,7 +2220,7 @@ ReportNotNullViolationError(ResultRelInfo *resultRelInfo, TupleTableSlot *slot,
modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate),
ExecGetUpdatedCols(resultRelInfo, estate));
- val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
+ val_desc = ExecBuildSlotValueDescription(rel,
slot,
tupdesc,
modifiedCols,
@@ -2313,7 +2328,7 @@ ExecWithCheckOptions(WCOKind kind, ResultRelInfo *resultRelInfo,
else
modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate),
ExecGetUpdatedCols(resultRelInfo, estate));
- val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel),
+ val_desc = ExecBuildSlotValueDescription(rel,
slot,
tupdesc,
modifiedCols,
@@ -2392,12 +2407,13 @@ ExecWithCheckOptions(WCOKind kind, ResultRelInfo *resultRelInfo,
* columns they are.
*/
char *
-ExecBuildSlotValueDescription(Oid reloid,
+ExecBuildSlotValueDescription(Relation rel,
TupleTableSlot *slot,
TupleDesc tupdesc,
Bitmapset *modifiedCols,
int maxfieldlen)
{
+ Oid reloid = RelationGetRelid(rel);
StringInfoData buf;
StringInfoData collist;
bool write_comma = false;
@@ -2477,7 +2493,23 @@ ExecBuildSlotValueDescription(Oid reloid,
if (table_perm || column_perm)
{
if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL)
- val = "virtual";
+ {
+ Node *genexpr = build_generation_expression(rel, att->attnum);
+ substitute_actual_values_context cxt;
+ List *dpcontext;
+
+ cxt.slot = slot;
+ cxt.tupdesc = tupdesc;
+ genexpr = substitute_actual_values_mutator(genexpr, &cxt);
+
+ /*
+ * We need dpcontext for any remaining Vars that weren't
+ * substituted (e.g system columns).
+ */
+ dpcontext = deparse_context_for(RelationGetRelationName(rel), reloid);
+
+ val = deparse_expression(genexpr, dpcontext, false, false);
+ }
else if (slot->tts_isnull[i])
val = "null";
else
@@ -3241,3 +3273,46 @@ EvalPlanQualEnd(EPQState *epqstate)
epqstate->relsubs_done = NULL;
epqstate->relsubs_blocked = NULL;
}
+
+/*
+ * Replaces Var nodes with Const nodes containing the actual values from the
+ * tuple slot.
+ *
+ * This is used to display the actual values used in virtual generated column
+ * expressions for error messages.
+ */
+static Node *
+substitute_actual_values_mutator(Node *node,
+ substitute_actual_values_context *context)
+{
+ if (node == NULL)
+ return NULL;
+
+ if (IsA(node, Var))
+ {
+ Var *var = (Var *) node;
+ int attnum = var->varattno;
+
+ if (attnum > 0 && attnum <= context->tupdesc->natts)
+ {
+ Form_pg_attribute att = TupleDescAttr(context->tupdesc, attnum - 1);
+ Datum value;
+ bool isnull;
+
+ value = context->slot->tts_values[attnum - 1];
+ isnull = context->slot->tts_isnull[attnum - 1];
+
+ return (Node *) makeConst(att->atttypid,
+ att->atttypmod,
+ att->attcollation,
+ att->attlen,
+ value,
+ isnull,
+ att->attbyval);
+ }
+ }
+
+ return expression_tree_mutator(node,
+ substitute_actual_values_mutator,
+ context);
+}
diff --git a/src/backend/replication/logical/conflict.c b/src/backend/replication/logical/conflict.c
index ca71a81c7bf..478c0a223fc 100644
--- a/src/backend/replication/logical/conflict.c
+++ b/src/backend/replication/logical/conflict.c
@@ -432,7 +432,6 @@ get_tuple_desc(EState *estate, ResultRelInfo *relinfo, ConflictType type,
Oid indexoid)
{
Relation localrel = relinfo->ri_RelationDesc;
- Oid relid = RelationGetRelid(localrel);
TupleDesc tupdesc = RelationGetDescr(localrel);
char *desc = NULL;
@@ -461,7 +460,7 @@ get_tuple_desc(EState *estate, ResultRelInfo *relinfo, ConflictType type,
* The 'modifiedCols' only applies to the new tuple, hence we pass
* NULL for the local row.
*/
- desc = ExecBuildSlotValueDescription(relid, localslot, tupdesc,
+ desc = ExecBuildSlotValueDescription(localrel, localslot, tupdesc,
NULL, 64);
if (desc)
@@ -481,7 +480,7 @@ get_tuple_desc(EState *estate, ResultRelInfo *relinfo, ConflictType type,
*/
modifiedCols = bms_union(ExecGetInsertedCols(relinfo, estate),
ExecGetUpdatedCols(relinfo, estate));
- desc = ExecBuildSlotValueDescription(relid, remoteslot,
+ desc = ExecBuildSlotValueDescription(localrel, remoteslot,
tupdesc, modifiedCols,
64);
@@ -510,7 +509,7 @@ get_tuple_desc(EState *estate, ResultRelInfo *relinfo, ConflictType type,
if (OidIsValid(replica_index))
desc = build_index_value_desc(estate, localrel, searchslot, replica_index);
else
- desc = ExecBuildSlotValueDescription(relid, searchslot, tupdesc, NULL, 64);
+ desc = ExecBuildSlotValueDescription(localrel, searchslot, tupdesc, NULL, 64);
if (desc)
{
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 55a7d930d26..2ffb97d48ca 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -269,7 +269,7 @@ extern void ExecPartitionCheckEmitError(ResultRelInfo *resultRelInfo,
TupleTableSlot *slot, EState *estate);
extern void ExecWithCheckOptions(WCOKind kind, ResultRelInfo *resultRelInfo,
TupleTableSlot *slot, EState *estate);
-extern char *ExecBuildSlotValueDescription(Oid reloid, TupleTableSlot *slot,
+extern char *ExecBuildSlotValueDescription(Relation rel, TupleTableSlot *slot,
TupleDesc tupdesc,
Bitmapset *modifiedCols,
int maxfieldlen);
diff --git a/src/test/regress/expected/generated_virtual.out b/src/test/regress/expected/generated_virtual.out
index 249e68be654..a55470fd47f 100644
--- a/src/test/regress/expected/generated_virtual.out
+++ b/src/test/regress/expected/generated_virtual.out
@@ -638,7 +638,7 @@ CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) VIRTU
INSERT INTO gtest20 (a) VALUES (10); -- ok
INSERT INTO gtest20 (a) VALUES (30); -- violates constraint
ERROR: new row for relation "gtest20" violates check constraint "gtest20_b_check"
-DETAIL: Failing row contains (30, virtual).
+DETAIL: Failing row contains (30, (30 * 2)).
ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100); -- violates constraint (currently not supported)
ERROR: ALTER TABLE / SET EXPRESSION is not supported for virtual generated columns in tables with check constraints
DETAIL: Column "b" of relation "gtest20" is a virtual generated column.
@@ -666,18 +666,18 @@ ALTER TABLE gtest20c ADD CONSTRAINT whole_row_check CHECK (gtest20c IS NOT NULL)
INSERT INTO gtest20c VALUES (1); -- ok
INSERT INTO gtest20c VALUES (NULL); -- fails
ERROR: new row for relation "gtest20c" violates check constraint "whole_row_check"
-DETAIL: Failing row contains (null, virtual).
+DETAIL: Failing row contains (null, (NULL::integer * 2)).
-- not-null constraints
CREATE TABLE gtest21a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL NOT NULL);
INSERT INTO gtest21a (a) VALUES (1); -- ok
INSERT INTO gtest21a (a) VALUES (0); -- violates constraint
ERROR: null value in column "b" of relation "gtest21a" violates not-null constraint
-DETAIL: Failing row contains (0, virtual).
+DETAIL: Failing row contains (0, NULLIF(0, 0)).
-- also check with table constraint syntax
CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL, CONSTRAINT cc NOT NULL b);
INSERT INTO gtest21ax (a) VALUES (0); -- violates constraint
ERROR: null value in column "b" of relation "gtest21ax" violates not-null constraint
-DETAIL: Failing row contains (0, virtual).
+DETAIL: Failing row contains (0, NULLIF(0, 0)).
INSERT INTO gtest21ax (a) VALUES (1); --ok
-- SET EXPRESSION supports not null constraint
ALTER TABLE gtest21ax ALTER COLUMN b SET EXPRESSION AS (nullif(a, 1)); --error
@@ -687,17 +687,17 @@ CREATE TABLE gtest21ax (a int PRIMARY KEY, b int GENERATED ALWAYS AS (nullif(a,
ALTER TABLE gtest21ax ADD CONSTRAINT cc NOT NULL b;
INSERT INTO gtest21ax (a) VALUES (0); -- violates constraint
ERROR: null value in column "b" of relation "gtest21ax" violates not-null constraint
-DETAIL: Failing row contains (0, virtual).
+DETAIL: Failing row contains (0, NULLIF(0, 0)).
DROP TABLE gtest21ax;
CREATE TABLE gtest21b (a int, b int GENERATED ALWAYS AS (nullif(a, 0)) VIRTUAL);
ALTER TABLE gtest21b ALTER COLUMN b SET NOT NULL;
INSERT INTO gtest21b (a) VALUES (1); -- ok
INSERT INTO gtest21b (a) VALUES (2), (0); -- violates constraint
ERROR: null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL: Failing row contains (0, virtual).
+DETAIL: Failing row contains (0, NULLIF(0, 0)).
INSERT INTO gtest21b (a) VALUES (NULL); -- error
ERROR: null value in column "b" of relation "gtest21b" violates not-null constraint
-DETAIL: Failing row contains (null, virtual).
+DETAIL: Failing row contains (null, NULLIF(NULL::integer, 0)).
ALTER TABLE gtest21b ALTER COLUMN b DROP NOT NULL;
INSERT INTO gtest21b (a) VALUES (0); -- ok now
-- not-null constraint with partitioned table
@@ -712,10 +712,10 @@ CREATE TABLE gtestnn_childdef PARTITION OF gtestnn_parent default;
INSERT INTO gtestnn_parent VALUES (2, 2, default), (3, 5, default), (14, 12, default); -- ok
INSERT INTO gtestnn_parent VALUES (1, 2, default); -- error
ERROR: null value in column "f3" of relation "gtestnn_child" violates not-null constraint
-DETAIL: Failing row contains (1, 2, virtual).
+DETAIL: Failing row contains (1, 2, (NULLIF(1, 1) + NULLIF('2'::bigint, 10))).
INSERT INTO gtestnn_parent VALUES (2, 10, default); -- error
ERROR: null value in column "f3" of relation "gtestnn_child" violates not-null constraint
-DETAIL: Failing row contains (2, 10, virtual).
+DETAIL: Failing row contains (2, 10, (NULLIF(2, 1) + NULLIF('10'::bigint, 10))).
ALTER TABLE gtestnn_parent ALTER COLUMN f3 SET EXPRESSION AS (nullif(f1, 2) + nullif(f2, 11)); -- error
ERROR: column "f3" of relation "gtestnn_child" contains null values
INSERT INTO gtestnn_parent VALUES (10, 11, default); -- ok
diff --git a/src/test/regress/expected/partition_merge.out b/src/test/regress/expected/partition_merge.out
index 925fe4f570a..ae40cb9cfcb 100644
--- a/src/test/regress/expected/partition_merge.out
+++ b/src/test/regress/expected/partition_merge.out
@@ -1073,7 +1073,7 @@ INSERT INTO t VALUES (16);
-- ERROR: new row for relation "tp_12" violates check constraint "t_i_check"
INSERT INTO t VALUES (0);
ERROR: new row for relation "tp_12" violates check constraint "t_i_check"
-DETAIL: Failing row contains (0, virtual).
+DETAIL: Failing row contains (0, (0 + (tableoid)::integer)).
-- Should be 3 rows: (5), (15), (16):
SELECT i FROM t ORDER BY i;
i
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 9f5ee8fd482..0bc6f86b884 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2950,6 +2950,7 @@ SubscriptingRefState
Subscription
SubscriptionInfo
SubscriptionRelState
+substitute_actual_values_context
SummarizerReadLocalXLogPrivate
SupportRequestCost
SupportRequestIndexCondition
--
2.52.0
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Subject: Re: Show expression of virtual columns in error messages
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