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* [PATCH v16 04/10] Add pg_ls_dir_metadata to list a dir with file metadata..
@ 2020-03-10 03:40 Justin Pryzby <[email protected]>
0 siblings, 0 replies; 3+ messages in thread
From: Justin Pryzby @ 2020-03-10 03:40 UTC (permalink / raw)
Generalize pg_ls_dir_files and retire pg_ls_dir
Need catversion bumped?
---
doc/src/sgml/func.sgml | 19 ++
src/backend/catalog/system_views.sql | 1 +
src/backend/utils/adt/genfile.c | 229 +++++++++++--------
src/include/catalog/pg_proc.dat | 12 +
src/test/regress/expected/misc_functions.out | 24 ++
src/test/regress/input/tablespace.source | 5 +
src/test/regress/output/tablespace.source | 8 +
src/test/regress/sql/misc_functions.sql | 11 +
8 files changed, 218 insertions(+), 91 deletions(-)
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 96b08d0500..9d617f95b9 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -25300,6 +25300,17 @@ postgres=# SELECT * FROM pg_walfile_name_offset(pg_stop_backup());
List the contents of a directory. Restricted to superusers by default, but other users can be granted EXECUTE to run the function.
</entry>
</row>
+ <row>
+ <entry>
+ <literal><function>pg_ls_dir_metadata(<parameter>dirname</parameter> <type>text</type> [, <parameter>missing_ok</parameter> <type>boolean</type>, <parameter>include_dot_dirs</parameter> <type>boolean</type>])</function></literal>
+ </entry>
+ <entry><type>setof text</type></entry>
+ <entry>
+ For each file in a directory, list the file and its metadata.
+ Restricted to superusers by default, but other users can be granted
+ EXECUTE to run the function.
+ </entry>
+ </row>
<row>
<entry>
<literal><function>pg_ls_logdir()</function></literal>
@@ -25400,6 +25411,14 @@ postgres=# SELECT * FROM pg_walfile_name_offset(pg_stop_backup());
empty directory from an non-existent directory.
</para>
+ <indexterm>
+ <primary>pg_ls_dir_metadata</primary>
+ </indexterm>
+ <para>
+ <function>pg_ls_dir_metadata</function> lists the files in the specified
+ directory along with the file's metadata.
+ </para>
+
<indexterm>
<primary>pg_ls_logdir</primary>
</indexterm>
diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql
index 2bd5f5ea14..1c77430f0c 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -1467,6 +1467,7 @@ REVOKE EXECUTE ON FUNCTION pg_stat_file(text,boolean) FROM public;
REVOKE EXECUTE ON FUNCTION pg_ls_dir(text) FROM public;
REVOKE EXECUTE ON FUNCTION pg_ls_dir(text,boolean,boolean) FROM public;
+REVOKE EXECUTE ON FUNCTION pg_ls_dir_metadata(text,boolean,boolean) FROM public;
--
-- We also set up some things as accessible to standard roles.
diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index 219ac160f8..4824a55480 100644
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -36,6 +36,21 @@
#include "utils/syscache.h"
#include "utils/timestamp.h"
+static Datum pg_ls_dir_files(FunctionCallInfo fcinfo, const char *dir, int flags);
+
+#define LS_DIR_ISDIR (1<<0) /* Show column: isdir */
+#define LS_DIR_METADATA (1<<1) /* Show columns: mtime, size */
+#define LS_DIR_MISSING_OK (1<<2) /* Ignore ENOENT if the toplevel dir is missing */
+#define LS_DIR_SKIP_DOT_DIRS (1<<3) /* Do not show . or .. */
+#define LS_DIR_SKIP_HIDDEN (1<<4) /* Do not show anything begining with . */
+#define LS_DIR_SKIP_DIRS (1<<5) /* Do not show directories */
+#define LS_DIR_SKIP_SPECIAL (1<<6) /* Do not show special file types */
+
+/*
+ * Shortcut for the historic behavior of the pg_ls_* functions (not including
+ * pg_ls_dir, which skips different files and doesn't show metadata.
+ */
+#define LS_DIR_HISTORIC (LS_DIR_SKIP_DIRS|LS_DIR_SKIP_HIDDEN|LS_DIR_SKIP_SPECIAL|LS_DIR_METADATA)
/*
* Convert a "text" filename argument to C string, and check it's allowable.
@@ -413,6 +428,11 @@ pg_stat_file(PG_FUNCTION_ARGS)
values[4] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
#endif
values[5] = BoolGetDatum(S_ISDIR(fst.st_mode));
+#ifdef WIN32
+ /* Links should have isdir=false */
+ if (pgwin32_is_junction(filename))
+ values[5] = BoolGetDatum(false);
+#endif
tuple = heap_form_tuple(tupdesc, values, isnull);
@@ -440,79 +460,9 @@ pg_stat_file_1arg(PG_FUNCTION_ARGS)
Datum
pg_ls_dir(PG_FUNCTION_ARGS)
{
- ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
- char *location;
- bool missing_ok = false;
- bool include_dot_dirs = false;
- bool randomAccess;
- TupleDesc tupdesc;
- Tuplestorestate *tupstore;
- DIR *dirdesc;
- struct dirent *de;
- MemoryContext oldcontext;
-
- location = convert_and_check_filename(PG_GETARG_TEXT_PP(0));
-
- /* check the optional arguments */
- if (PG_NARGS() == 3)
- {
- if (!PG_ARGISNULL(1))
- missing_ok = PG_GETARG_BOOL(1);
- if (!PG_ARGISNULL(2))
- include_dot_dirs = PG_GETARG_BOOL(2);
- }
-
- /* check to see if caller supports us returning a tuplestore */
- if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("set-valued function called in context that cannot accept a set")));
- if (!(rsinfo->allowedModes & SFRM_Materialize))
- ereport(ERROR,
- (errcode(ERRCODE_SYNTAX_ERROR),
- errmsg("materialize mode required, but it is not allowed in this context")));
-
- /* The tupdesc and tuplestore must be created in ecxt_per_query_memory */
- oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
-
- tupdesc = CreateTemplateTupleDesc(1);
- TupleDescInitEntry(tupdesc, (AttrNumber) 1, "pg_ls_dir", TEXTOID, -1, 0);
-
- randomAccess = (rsinfo->allowedModes & SFRM_Materialize_Random) != 0;
- tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
- rsinfo->returnMode = SFRM_Materialize;
- rsinfo->setResult = tupstore;
- rsinfo->setDesc = tupdesc;
-
- MemoryContextSwitchTo(oldcontext);
-
- dirdesc = AllocateDir(location);
- if (!dirdesc)
- {
- /* Return empty tuplestore if appropriate */
- if (missing_ok && errno == ENOENT)
- return (Datum) 0;
- /* Otherwise, we can let ReadDir() throw the error */
- }
-
- while ((de = ReadDir(dirdesc, location)) != NULL)
- {
- Datum values[1];
- bool nulls[1];
-
- if (!include_dot_dirs &&
- (strcmp(de->d_name, ".") == 0 ||
- strcmp(de->d_name, "..") == 0))
- continue;
-
- values[0] = CStringGetTextDatum(de->d_name);
- nulls[0] = false;
-
- tuplestore_putvalues(tupstore, tupdesc, values, nulls);
- }
-
- FreeDir(dirdesc);
- return (Datum) 0;
+ text *filename_t = PG_GETARG_TEXT_PP(0);
+ char *filename = convert_and_check_filename(filename_t);
+ return pg_ls_dir_files(fcinfo, filename, LS_DIR_SKIP_DOT_DIRS);
}
/*
@@ -525,7 +475,9 @@ pg_ls_dir(PG_FUNCTION_ARGS)
Datum
pg_ls_dir_1arg(PG_FUNCTION_ARGS)
{
- return pg_ls_dir(fcinfo);
+ text *filename_t = PG_GETARG_TEXT_PP(0);
+ char *filename = convert_and_check_filename(filename_t);
+ return pg_ls_dir_files(fcinfo, filename, LS_DIR_SKIP_DOT_DIRS);
}
/*
@@ -535,7 +487,7 @@ pg_ls_dir_1arg(PG_FUNCTION_ARGS)
* Other unreadable-directory cases throw an error.
*/
static Datum
-pg_ls_dir_files(FunctionCallInfo fcinfo, const char *dir, bool missing_ok)
+pg_ls_dir_files(FunctionCallInfo fcinfo, const char *dir, int flags)
{
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
bool randomAccess;
@@ -544,6 +496,32 @@ pg_ls_dir_files(FunctionCallInfo fcinfo, const char *dir, bool missing_ok)
DIR *dirdesc;
struct dirent *de;
MemoryContext oldcontext;
+ TypeFuncClass tuptype ;
+
+ /* isdir depends on metadata */
+ Assert(!(flags&LS_DIR_ISDIR) || (flags&LS_DIR_METADATA));
+ /* Unreasonable to show isdir and skip dirs */
+ Assert(!(flags&LS_DIR_ISDIR) || !(flags&LS_DIR_SKIP_DIRS));
+
+ /* check the optional arguments */
+ if (PG_NARGS() == 3)
+ {
+ if (!PG_ARGISNULL(1))
+ {
+ if (PG_GETARG_BOOL(1))
+ flags |= LS_DIR_MISSING_OK;
+ else
+ flags &= ~LS_DIR_MISSING_OK;
+ }
+
+ if (!PG_ARGISNULL(2))
+ {
+ if (PG_GETARG_BOOL(2))
+ flags &= ~LS_DIR_SKIP_DOT_DIRS;
+ else
+ flags |= LS_DIR_SKIP_DOT_DIRS;
+ }
+ }
/* check to see if caller supports us returning a tuplestore */
if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
@@ -558,8 +536,20 @@ pg_ls_dir_files(FunctionCallInfo fcinfo, const char *dir, bool missing_ok)
/* The tupdesc and tuplestore must be created in ecxt_per_query_memory */
oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
- if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
- elog(ERROR, "return type must be a row type");
+ tuptype = get_call_result_type(fcinfo, NULL, &tupdesc);
+ if (flags & LS_DIR_METADATA)
+ {
+ if (tuptype != TYPEFUNC_COMPOSITE)
+ elog(ERROR, "return type must be a row type");
+ }
+ else
+ {
+ /* pg_ls_dir returns a simple scalar */
+ if (tuptype != TYPEFUNC_SCALAR)
+ elog(ERROR, "return type must be a scalar type");
+ tupdesc = CreateTemplateTupleDesc(1);
+ TupleDescInitEntry(tupdesc, (AttrNumber) 1, "column", TEXTOID, -1, 0);
+ }
randomAccess = (rsinfo->allowedModes & SFRM_Materialize_Random) != 0;
tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
@@ -578,20 +568,27 @@ pg_ls_dir_files(FunctionCallInfo fcinfo, const char *dir, bool missing_ok)
if (!dirdesc)
{
/* Return empty tuplestore if appropriate */
- if (missing_ok && errno == ENOENT)
+ if (flags & LS_DIR_MISSING_OK && errno == ENOENT)
return (Datum) 0;
/* Otherwise, we can let ReadDir() throw the error */
}
while ((de = ReadDir(dirdesc, dir)) != NULL)
{
- Datum values[3];
- bool nulls[3];
+ Datum values[4];
+ bool nulls[4];
char path[MAXPGPATH * 2];
struct stat attrib;
- /* Skip hidden files */
- if (de->d_name[0] == '.')
+ /* Skip dot dirs? */
+ if (flags & LS_DIR_SKIP_DOT_DIRS &&
+ (strcmp(de->d_name, ".") == 0 ||
+ strcmp(de->d_name, "..") == 0))
+ continue;
+
+ /* Skip hidden files? */
+ if (flags & LS_DIR_SKIP_HIDDEN &&
+ de->d_name[0] == '.')
continue;
/* Get the file info */
@@ -606,13 +603,34 @@ pg_ls_dir_files(FunctionCallInfo fcinfo, const char *dir, bool missing_ok)
errmsg("could not stat file \"%s\": %m", path)));
}
- /* Ignore anything but regular files */
- if (!S_ISREG(attrib.st_mode))
- continue;
+ /* Skip dirs or special files? */
+ if (S_ISDIR(attrib.st_mode))
+ {
+ if (flags & LS_DIR_SKIP_DIRS)
+ continue;
+ }
+ else if (!S_ISREG(attrib.st_mode))
+ {
+ if (flags & LS_DIR_SKIP_SPECIAL)
+ continue;
+ }
values[0] = CStringGetTextDatum(de->d_name);
- values[1] = Int64GetDatum((int64) attrib.st_size);
- values[2] = TimestampTzGetDatum(time_t_to_timestamptz(attrib.st_mtime));
+ if (flags & LS_DIR_METADATA)
+ {
+ values[1] = Int64GetDatum((int64) attrib.st_size);
+ values[2] = TimestampTzGetDatum(time_t_to_timestamptz(attrib.st_mtime));
+ if (flags & LS_DIR_ISDIR)
+ {
+ values[3] = BoolGetDatum(S_ISDIR(attrib.st_mode));
+#ifdef WIN32
+ /* Links should have isdir=false */
+ if (pgwin32_is_junction(path))
+ values[3] = BoolGetDatum(false);
+#endif
+ }
+ }
+
memset(nulls, 0, sizeof(nulls));
tuplestore_putvalues(tupstore, tupdesc, values, nulls);
@@ -626,14 +644,14 @@ pg_ls_dir_files(FunctionCallInfo fcinfo, const char *dir, bool missing_ok)
Datum
pg_ls_logdir(PG_FUNCTION_ARGS)
{
- return pg_ls_dir_files(fcinfo, Log_directory, false);
+ return pg_ls_dir_files(fcinfo, Log_directory, LS_DIR_HISTORIC);
}
/* Function to return the list of files in the WAL directory */
Datum
pg_ls_waldir(PG_FUNCTION_ARGS)
{
- return pg_ls_dir_files(fcinfo, XLOGDIR, false);
+ return pg_ls_dir_files(fcinfo, XLOGDIR, LS_DIR_HISTORIC);
}
/*
@@ -651,7 +669,8 @@ pg_ls_tmpdir(FunctionCallInfo fcinfo, Oid tblspc)
tblspc)));
TempTablespacePath(path, tblspc);
- return pg_ls_dir_files(fcinfo, path, true);
+ return pg_ls_dir_files(fcinfo, path,
+ LS_DIR_HISTORIC | LS_DIR_MISSING_OK);
}
/*
@@ -680,5 +699,33 @@ pg_ls_tmpdir_1arg(PG_FUNCTION_ARGS)
Datum
pg_ls_archive_statusdir(PG_FUNCTION_ARGS)
{
- return pg_ls_dir_files(fcinfo, XLOGDIR "/archive_status", true);
+ return pg_ls_dir_files(fcinfo, XLOGDIR "/archive_status",
+ LS_DIR_HISTORIC | LS_DIR_MISSING_OK);
+}
+
+/*
+ * Function to return the list of files and metadata in an arbitrary directory.
+ */
+Datum
+pg_ls_dir_metadata(PG_FUNCTION_ARGS)
+{
+ char *dirname = convert_and_check_filename(PG_GETARG_TEXT_PP(0));
+
+ return pg_ls_dir_files(fcinfo, dirname,
+ LS_DIR_METADATA | LS_DIR_SKIP_SPECIAL | LS_DIR_ISDIR);
+}
+
+/*
+ * Function to return the list of files and metadata in an arbitrary directory.
+ * note: this wrapper is necessary to pass the sanity check in opr_sanity,
+ * which checks that all built-in functions that share the implementing C
+ * function take the same number of arguments.
+ */
+Datum
+pg_ls_dir_metadata_1arg(PG_FUNCTION_ARGS)
+{
+ char *dirname = convert_and_check_filename(PG_GETARG_TEXT_PP(0));
+
+ return pg_ls_dir_files(fcinfo, dirname,
+ LS_DIR_METADATA | LS_DIR_SKIP_SPECIAL | LS_DIR_ISDIR);
}
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 4bce3ad8de..9f46cba5ed 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -10904,6 +10904,18 @@
proallargtypes => '{oid,text,int8,timestamptz}', proargmodes => '{i,o,o,o}',
proargnames => '{tablespace,name,size,modification}',
prosrc => 'pg_ls_tmpdir_1arg' },
+{ oid => '5032', descr => 'list directory with metadata',
+ proname => 'pg_ls_dir_metadata', procost => '10', prorows => '20', proretset => 't',
+ provolatile => 'v', prorettype => 'record', proargtypes => 'text bool bool',
+ proallargtypes => '{text,bool,bool,text,int8,timestamptz,bool}', proargmodes => '{i,i,i,o,o,o,o}',
+ proargnames => '{dirname,missing_ok,include_dot_dirs,name,size,modification,isdir}',
+ prosrc => 'pg_ls_dir_metadata' },
+{ oid => '5033', descr => 'list directory with metadata',
+ proname => 'pg_ls_dir_metadata', procost => '10', prorows => '20', proretset => 't',
+ provolatile => 'v', prorettype => 'record', proargtypes => 'text',
+ proallargtypes => '{text,text,int8,timestamptz,bool}', proargmodes => '{i,o,o,o,o}',
+ proargnames => '{dirname,name,size,modification,isdir}',
+ prosrc => 'pg_ls_dir_metadata_1arg' },
# hash partitioning constraint function
{ oid => '5028', descr => 'hash partition CHECK constraint',
diff --git a/src/test/regress/expected/misc_functions.out b/src/test/regress/expected/misc_functions.out
index 2e87c548eb..7930909f02 100644
--- a/src/test/regress/expected/misc_functions.out
+++ b/src/test/regress/expected/misc_functions.out
@@ -219,6 +219,30 @@ select pg_ls_dir('does not exist', true, false); -- ok with missingok=true
select pg_ls_dir('does not exist'); -- fails with missingok=false
ERROR: could not open directory "does not exist": No such file or directory
+-- This tests the missing_ok parameter, which causes pg_ls_tmpdir to succeed even if the tmpdir doesn't exist yet
+-- The name='' condition is never true, so the function runs to completion but returns zero rows.
+select * from pg_ls_tmpdir() where name='Does not exist';
+ name | size | modification
+------+------+--------------
+(0 rows)
+
+select name, isdir from pg_ls_dir_metadata('.') where name='.';
+ name | isdir
+------+-------
+ . | t
+(1 row)
+
+select name, isdir from pg_ls_dir_metadata('.', false, false) where name='.'; -- include_dot_dirs=false
+ name | isdir
+------+-------
+(0 rows)
+
+-- Check that expected columns are present
+select * from pg_ls_dir_metadata('.') limit 0;
+ name | size | modification | isdir
+------+------+--------------+-------
+(0 rows)
+
--
-- Test adding a support function to a subject function
--
diff --git a/src/test/regress/input/tablespace.source b/src/test/regress/input/tablespace.source
index a5f61a35dc..0b9cfe615e 100644
--- a/src/test/regress/input/tablespace.source
+++ b/src/test/regress/input/tablespace.source
@@ -11,6 +11,11 @@ DROP TABLESPACE regress_tblspacewith;
-- create a tablespace we can use
CREATE TABLESPACE regress_tblspace LOCATION '@testtablespace@';
+-- This tests the missing_ok parameter, which causes pg_ls_tmpdir to succeed even if the tmpdir doesn't exist yet
+-- The name='' condition is never true, so the function runs to completion but returns zero rows.
+-- The query is written to ERROR if the tablespace doesn't exist, rather than silently failing to call pg_ls_tmpdir()
+SELECT c.* FROM (SELECT oid FROM pg_tablespace b WHERE b.spcname='regress_tblspace' UNION SELECT 0 ORDER BY 1 DESC LIMIT 1) AS b , pg_ls_tmpdir(oid) AS c WHERE c.name='Does not exist';
+
-- try setting and resetting some properties for the new tablespace
ALTER TABLESPACE regress_tblspace SET (random_page_cost = 1.0, seq_page_cost = 1.1);
ALTER TABLESPACE regress_tblspace SET (some_nonexistent_parameter = true); -- fail
diff --git a/src/test/regress/output/tablespace.source b/src/test/regress/output/tablespace.source
index 162b591b31..a42714bf40 100644
--- a/src/test/regress/output/tablespace.source
+++ b/src/test/regress/output/tablespace.source
@@ -13,6 +13,14 @@ SELECT spcoptions FROM pg_tablespace WHERE spcname = 'regress_tblspacewith';
DROP TABLESPACE regress_tblspacewith;
-- create a tablespace we can use
CREATE TABLESPACE regress_tblspace LOCATION '@testtablespace@';
+-- This tests the missing_ok parameter, which causes pg_ls_tmpdir to succeed even if the tmpdir doesn't exist yet
+-- The name='' condition is never true, so the function runs to completion but returns zero rows.
+-- The query is written to ERROR if the tablespace doesn't exist, rather than silently failing to call pg_ls_tmpdir()
+SELECT c.* FROM (SELECT oid FROM pg_tablespace b WHERE b.spcname='regress_tblspace' UNION SELECT 0 ORDER BY 1 DESC LIMIT 1) AS b , pg_ls_tmpdir(oid) AS c WHERE c.name='Does not exist';
+ name | size | modification
+------+------+--------------
+(0 rows)
+
-- try setting and resetting some properties for the new tablespace
ALTER TABLESPACE regress_tblspace SET (random_page_cost = 1.0, seq_page_cost = 1.1);
ALTER TABLESPACE regress_tblspace SET (some_nonexistent_parameter = true); -- fail
diff --git a/src/test/regress/sql/misc_functions.sql b/src/test/regress/sql/misc_functions.sql
index f6857ad177..372345720d 100644
--- a/src/test/regress/sql/misc_functions.sql
+++ b/src/test/regress/sql/misc_functions.sql
@@ -65,6 +65,17 @@ select * from (select pg_ls_dir('.', false, false) as name) as ls where ls.name=
select pg_ls_dir('does not exist', true, false); -- ok with missingok=true
select pg_ls_dir('does not exist'); -- fails with missingok=false
+-- This tests the missing_ok parameter, which causes pg_ls_tmpdir to succeed even if the tmpdir doesn't exist yet
+-- The name='' condition is never true, so the function runs to completion but returns zero rows.
+select * from pg_ls_tmpdir() where name='Does not exist';
+
+select name, isdir from pg_ls_dir_metadata('.') where name='.';
+
+select name, isdir from pg_ls_dir_metadata('.', false, false) where name='.'; -- include_dot_dirs=false
+
+-- Check that expected columns are present
+select * from pg_ls_dir_metadata('.') limit 0;
+
--
-- Test adding a support function to a subject function
--
--
2.17.0
--2FkSFaIQeDFoAt0B
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v16-0005-pg_ls_tmpdir-to-show-directories-and-isdir-argum.patch"
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: Show expression of virtual columns in error messages
@ 2026-02-04 17:54 Matheus Alcantara <[email protected]>
0 siblings, 1 reply; 3+ messages in thread
From: Matheus Alcantara @ 2026-02-04 17:54 UTC (permalink / raw)
To: Peter Eisentraut <[email protected]>; Matheus Alcantara <[email protected]>; [email protected]
On Wed Feb 4, 2026 at 11:57 AM -03, Peter Eisentraut wrote:
> On 03.02.26 15:06, Matheus Alcantara wrote:
>> The attached patch changes this behavior to show the virtual column
>> expression instead:
>>
>> ERROR: new row for relation "t" violates check constraint "t_c_check"
>> DETAIL: Failing row contains (5, 10, a * 2).
>
> Could be useful, but in this context you don't know which column is "a"?
I agree but we at least show more information to the user. The user may
still need to check the table definition to understand the constraint or
to get the column ordering of the table to understand what the value of
"a" is being used to compute the expression.
If the statement declare the columns that the values are referecing this
could be easier to know (e.g INSERT INTO t(a, b) VALUES (5, 10)) but the
user may still need to check the table definition to understand the
constraint.
I see this patch as a way to at least give more information to user
about the error.
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).
--
Matheus Alcantara
EDB: https://www.enterprisedb.com
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: Show expression of virtual columns in error messages
@ 2026-02-05 02:45 Yugo Nagata <[email protected]>
parent: Matheus Alcantara <[email protected]>
0 siblings, 0 replies; 3+ messages in thread
From: Yugo Nagata @ 2026-02-05 02:45 UTC (permalink / raw)
To: Matheus Alcantara <[email protected]>; +Cc: Peter Eisentraut <[email protected]>; [email protected]
On Wed, 04 Feb 2026 14:54:11 -0300
"Matheus Alcantara" <[email protected]> wrote:
> On Wed Feb 4, 2026 at 11:57 AM -03, Peter Eisentraut wrote:
> > On 03.02.26 15:06, Matheus Alcantara wrote:
> >> The attached patch changes this behavior to show the virtual column
> >> expression instead:
> >>
> >> ERROR: new row for relation "t" violates check constraint "t_c_check"
> >> DETAIL: Failing row contains (5, 10, a * 2).
> >
> > Could be useful, but in this context you don't know which column is "a"?
>
> I agree but we at least show more information to the user. The user may
> still need to check the table definition to understand the constraint or
> to get the column ordering of the table to understand what the value of
> "a" is being used to compute the expression.
>
> If the statement declare the columns that the values are referecing this
> could be easier to know (e.g INSERT INTO t(a, b) VALUES (5, 10)) but the
> user may still need to check the table definition to understand the
> constraint.
>
> I see this patch as a way to at least give more information to user
> about the error.
>
> 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.
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.
Regards,
Yugo Nagata
--
Yugo Nagata <[email protected]>
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2020-03-10 03:40 [PATCH v16 04/10] Add pg_ls_dir_metadata to list a dir with file metadata.. Justin Pryzby <[email protected]>
2026-02-04 17:54 Re: Show expression of virtual columns in error messages Matheus Alcantara <[email protected]>
2026-02-05 02:45 ` Re: Show expression of virtual columns in error messages Yugo Nagata <[email protected]>
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