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Add SQL functions to monitor the directory contents of replication slots 

This commit adds a set of functions able to look at the contents of
various paths related to replication slots:
- pg_ls_logicalsnapdir, for pg_logical/snapshots/
- pg_ls_logicalmapdir, for pg_logical/mappings/
- pg_ls_replslotdir, for pg_replslot/<slot_name>/

These are intended to be used by monitoring tools.  Unlike pg_ls_dir(),
execution permission can be granted to non-superusers.  Roles members of
pg_monitor gain have access to those functions.

Bump catalog version.

Author: Bharath Rupireddy
Reviewed-by: Nathan Bossart, Justin Pryzby
Discussion: https://postgr.es/m/CALj2ACWsfizZjMN6bzzdxOk1ADQQeSw8HhEjhmVXn_Pu+7VzLw@mail.gmail.com
This commit is contained in:
Michael Paquier 2021-11-23 19:29:42 +09:00
parent b55f2b6926
commit 1922d7c6e1
9 changed files with 250 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
contrib/test_decoding/expected/slot.out
View File

@ -48,6 +48,27 @@ SELECT pg_drop_replication_slot('regression_slot_t');
ERROR: replication slot "regression_slot_t" does not exist
SELECT pg_drop_replication_slot('regression_slot_t2');
ERROR: replication slot "regression_slot_t2" does not exist
-- monitoring functions for slot directories
SELECT count(*) >= 0 AS ok FROM pg_ls_logicalmapdir();
ok
----
t
(1 row)
SELECT count(*) >= 0 AS ok FROM pg_ls_logicalsnapdir();
ok
----
t
(1 row)
SELECT count(*) >= 0 AS ok FROM pg_ls_replslotdir('regression_slot_p');
ok
----
t
(1 row)
SELECT count(*) >= 0 AS ok FROM pg_ls_replslotdir('not_existing_slot'); -- fails
ERROR: replication slot "not_existing_slot" does not exist
-- permanent slot has survived
SELECT pg_drop_replication_slot('regression_slot_p');
pg_drop_replication_slot

6
contrib/test_decoding/sql/slot.sql
View File

@ -28,6 +28,12 @@ end';
SELECT pg_drop_replication_slot('regression_slot_t');
SELECT pg_drop_replication_slot('regression_slot_t2');
-- monitoring functions for slot directories
SELECT count(*) >= 0 AS ok FROM pg_ls_logicalmapdir();
SELECT count(*) >= 0 AS ok FROM pg_ls_logicalsnapdir();
SELECT count(*) >= 0 AS ok FROM pg_ls_replslotdir('regression_slot_p');
SELECT count(*) >= 0 AS ok FROM pg_ls_replslotdir('not_existing_slot'); -- fails
-- permanent slot has survived
SELECT pg_drop_replication_slot('regression_slot_p');

73
doc/src/sgml/func.sgml
View File

@ -27417,6 +27417,79 @@ SELECT convert_from(pg_read_binary_file('file_in_utf8.txt'), 'UTF8');
can be granted EXECUTE to run the function.
</para></entry>
</row>
<row>
<entry role="func_table_entry"><para role="func_signature">
<indexterm>
<primary>pg_ls_logicalsnapdir</primary>
</indexterm>
<function>pg_ls_logicalsnapdir</function> ()
<returnvalue>setof record</returnvalue>
( <parameter>name</parameter> <type>text</type>,
<parameter>size</parameter> <type>bigint</type>,
<parameter>modification</parameter> <type>timestamp with time zone</type> )
</para>
<para>
Returns the name, size, and last modification time (mtime) of each
ordinary file in the server's <filename>pg_logical/snapshots</filename>
directory. Filenames beginning with a dot, directories, and other
special files are excluded.
</para>
<para>
This function is restricted to superusers and members of
the <literal>pg_monitor</literal> role by default, but other users can
be granted EXECUTE to run the function.
</para></entry>
</row>
<row>
<entry role="func_table_entry"><para role="func_signature">
<indexterm>
<primary>pg_ls_logicalmapdir</primary>
</indexterm>
<function>pg_ls_logicalmapdir</function> ()
<returnvalue>setof record</returnvalue>
( <parameter>name</parameter> <type>text</type>,
<parameter>size</parameter> <type>bigint</type>,
<parameter>modification</parameter> <type>timestamp with time zone</type> )
</para>
<para>
Returns the name, size, and last modification time (mtime) of each
ordinary file in the server's <filename>pg_logical/mappings</filename>
directory. Filenames beginning with a dot, directories, and other
special files are excluded.
</para>
<para>
This function is restricted to superusers and members of
the <literal>pg_monitor</literal> role by default, but other users can
be granted EXECUTE to run the function.
</para></entry>
</row>
<row>
<entry role="func_table_entry"><para role="func_signature">
<indexterm>
<primary>pg_ls_replslotdir</primary>
</indexterm>
<function>pg_ls_replslotdir</function> ( <parameter>slot_name</parameter> <type>text</type> )
<returnvalue>setof record</returnvalue>
( <parameter>name</parameter> <type>text</type>,
<parameter>size</parameter> <type>bigint</type>,
<parameter>modification</parameter> <type>timestamp with time zone</type> )
</para>
<para>
Returns the name, size, and last modification time (mtime) of each
ordinary file in the server's <filename>pg_replslot/slot_name</filename>
directory, where <parameter>slot_name</parameter> is the name of the
replication slot provided as input of the function. Filenames beginning
with a dot, directories, and other special files are excluded.
</para>
<para>
This function is restricted to superusers and members of
the <literal>pg_monitor</literal> role by default, but other users can
be granted EXECUTE to run the function.
</para></entry>
</row>
</tbody>
</tgroup>
</table>

12
src/backend/catalog/system_functions.sql
View File

@ -701,6 +701,12 @@ REVOKE EXECUTE ON FUNCTION pg_ls_dir(text,boolean,boolean) FROM public;
REVOKE EXECUTE ON FUNCTION pg_log_backend_memory_contexts(integer) FROM PUBLIC;
REVOKE EXECUTE ON FUNCTION pg_ls_logicalsnapdir() FROM PUBLIC;
REVOKE EXECUTE ON FUNCTION pg_ls_logicalmapdir() FROM PUBLIC;
REVOKE EXECUTE ON FUNCTION pg_ls_replslotdir(text) FROM PUBLIC;
--
-- We also set up some things as accessible to standard roles.
--
@ -715,6 +721,12 @@ GRANT EXECUTE ON FUNCTION pg_ls_tmpdir() TO pg_monitor;
GRANT EXECUTE ON FUNCTION pg_ls_tmpdir(oid) TO pg_monitor;
GRANT EXECUTE ON FUNCTION pg_ls_logicalsnapdir() TO pg_monitor;
GRANT EXECUTE ON FUNCTION pg_ls_logicalmapdir() TO pg_monitor;
GRANT EXECUTE ON FUNCTION pg_ls_replslotdir(text) TO pg_monitor;
GRANT pg_read_all_settings TO pg_monitor;
GRANT pg_read_all_stats TO pg_monitor;

44
src/backend/utils/adt/genfile.c
View File

@ -29,6 +29,7 @@
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "postmaster/syslogger.h"
#include "replication/slot.h"
#include "storage/fd.h"
#include "utils/acl.h"
#include "utils/builtins.h"
@ -720,3 +721,46 @@ pg_ls_archive_statusdir(PG_FUNCTION_ARGS)
{
return pg_ls_dir_files(fcinfo, XLOGDIR "/archive_status", true);
}
/*
* Function to return the list of files in the pg_logical/snapshots directory.
*/
Datum
pg_ls_logicalsnapdir(PG_FUNCTION_ARGS)
{
return pg_ls_dir_files(fcinfo, "pg_logical/snapshots", false);
}
/*
* Function to return the list of files in the pg_logical/mappings directory.
*/
Datum
pg_ls_logicalmapdir(PG_FUNCTION_ARGS)
{
return pg_ls_dir_files(fcinfo, "pg_logical/mappings", false);
}
/*
* Function to return the list of files in the pg_replslot/<replication_slot>
* directory.
*/
Datum
pg_ls_replslotdir(PG_FUNCTION_ARGS)
{
text *slotname_t;
char path[MAXPGPATH];
char *slotname;
slotname_t = PG_GETARG_TEXT_PP(0);
slotname = text_to_cstring(slotname_t);
if (!SearchNamedReplicationSlot(slotname, true))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("replication slot \"%s\" does not exist",
slotname)));
snprintf(path, sizeof(path), "pg_replslot/%s", slotname);
return pg_ls_dir_files(fcinfo, path, false);
}

2
src/include/catalog/catversion.h
View File

@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 202111171
#define CATALOG_VERSION_NO 202111231
#endif

22
src/include/catalog/pg_proc.dat
View File

@ -11623,6 +11623,28 @@
proallargtypes => '{oid,text,int8,timestamptz}', proargmodes => '{i,o,o,o}',
proargnames => '{tablespace,name,size,modification}',
prosrc => 'pg_ls_tmpdir_1arg' },
{ oid => '9858',
descr => 'list of files in the pg_logical/snapshots directory',
proname => 'pg_ls_logicalsnapdir', procost => '10', prorows => '20',
proretset => 't', provolatile => 'v', prorettype => 'record',
proargtypes => '', proallargtypes => '{text,int8,timestamptz}',
proargmodes => '{o,o,o}', proargnames => '{name,size,modification}',
prosrc => 'pg_ls_logicalsnapdir' },
{ oid => '9859',
descr => 'list of files in the pg_logical/mappings directory',
proname => 'pg_ls_logicalmapdir', procost => '10', prorows => '20',
proretset => 't', provolatile => 'v', prorettype => 'record',
proargtypes => '', proallargtypes => '{text,int8,timestamptz}',
proargmodes => '{o,o,o}', proargnames => '{name,size,modification}',
prosrc => 'pg_ls_logicalmapdir' },
{ oid => '9860',
descr => 'list of files in the pg_replslot/slot_name directory',
proname => 'pg_ls_replslotdir', procost => '10', prorows => '20',
proretset => 't', provolatile => 'v', prorettype => 'record',
proargtypes => 'text', proallargtypes => '{text,text,int8,timestamptz}',
proargmodes => '{i,o,o,o}',
proargnames => '{slot_name,name,size,modification}',
prosrc => 'pg_ls_replslotdir' },
# hash partitioning constraint function
{ oid => '5028', descr => 'hash partition CHECK constraint',

50
src/test/regress/expected/misc_functions.out
View File

@ -243,6 +243,56 @@ select count(*) > 0 from
t
(1 row)
--
-- Test replication slot directory functions
--
CREATE ROLE regress_slot_dir_funcs;
-- Not available by default.
SELECT has_function_privilege('regress_slot_dir_funcs',
'pg_ls_logicalsnapdir()', 'EXECUTE');
has_function_privilege
------------------------
f
(1 row)
SELECT has_function_privilege('regress_slot_dir_funcs',
'pg_ls_logicalmapdir()', 'EXECUTE');
has_function_privilege
------------------------
f
(1 row)
SELECT has_function_privilege('regress_slot_dir_funcs',
'pg_ls_replslotdir(text)', 'EXECUTE');
has_function_privilege
------------------------
f
(1 row)
GRANT pg_monitor TO regress_slot_dir_funcs;
-- Role is now part of pg_monitor, so these are available.
SELECT has_function_privilege('regress_slot_dir_funcs',
'pg_ls_logicalsnapdir()', 'EXECUTE');
has_function_privilege
------------------------
t
(1 row)
SELECT has_function_privilege('regress_slot_dir_funcs',
'pg_ls_logicalmapdir()', 'EXECUTE');
has_function_privilege
------------------------
t
(1 row)
SELECT has_function_privilege('regress_slot_dir_funcs',
'pg_ls_replslotdir(text)', 'EXECUTE');
has_function_privilege
------------------------
t
(1 row)
DROP ROLE regress_slot_dir_funcs;
--
-- Test adding a support function to a subject function
--

21
src/test/regress/sql/misc_functions.sql
View File

@ -91,6 +91,27 @@ select count(*) > 0 from
where spcname = 'pg_default') pts
join pg_database db on pts.pts = db.oid;
--
-- Test replication slot directory functions
--
CREATE ROLE regress_slot_dir_funcs;
-- Not available by default.
SELECT has_function_privilege('regress_slot_dir_funcs',
'pg_ls_logicalsnapdir()', 'EXECUTE');
SELECT has_function_privilege('regress_slot_dir_funcs',
'pg_ls_logicalmapdir()', 'EXECUTE');
SELECT has_function_privilege('regress_slot_dir_funcs',
'pg_ls_replslotdir(text)', 'EXECUTE');
GRANT pg_monitor TO regress_slot_dir_funcs;
-- Role is now part of pg_monitor, so these are available.
SELECT has_function_privilege('regress_slot_dir_funcs',
'pg_ls_logicalsnapdir()', 'EXECUTE');
SELECT has_function_privilege('regress_slot_dir_funcs',
'pg_ls_logicalmapdir()', 'EXECUTE');
SELECT has_function_privilege('regress_slot_dir_funcs',
'pg_ls_replslotdir(text)', 'EXECUTE');
DROP ROLE regress_slot_dir_funcs;
--
-- Test adding a support function to a subject function
--