diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f9d7a8f9c35..f1ce1db6bcd 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -28163,6 +28163,10 @@ acl | {postgres=arwdDxtm/postgres,foo=r/postgres}
calling role is a member of the role whose backend is being canceled or
the calling role has privileges of pg_signal_backend,
however only superusers can cancel superuser backends.
+ As an exception, roles with privileges of
+ pg_signal_autovacuum_worker are permitted to
+ cancel autovacuum worker processes, which are otherwise considered
+ superuser backends.
@@ -28237,6 +28241,10 @@ acl | {postgres=arwdDxtm/postgres,foo=r/postgres}
is a member of the role whose backend is being terminated or the
calling role has privileges of pg_signal_backend,
however only superusers can terminate superuser backends.
+ As an exception, roles with privileges of
+ pg_signal_autovacuum_worker are permitted to
+ terminate autovacuum worker processes, which are otherwise considered
+ superuser backends.
If timeout is not specified or zero, this
diff --git a/doc/src/sgml/user-manag.sgml b/doc/src/sgml/user-manag.sgml
index 07a16247d76..340cefff705 100644
--- a/doc/src/sgml/user-manag.sgml
+++ b/doc/src/sgml/user-manag.sgml
@@ -661,6 +661,11 @@ DROP ROLE doomed_role;
pg_signal_backend
Signal another backend to cancel a query or terminate its session.
+
+ pg_signal_autovacuum_worker
+ Signal an autovacuum worker to cancel the current table's vacuum
+ or terminate its session.
+
pg_read_server_files
Allow reading files from any location the database can access on the server with COPY and
diff --git a/src/backend/storage/ipc/signalfuncs.c b/src/backend/storage/ipc/signalfuncs.c
index 88e9bf8125d..aa729a36e39 100644
--- a/src/backend/storage/ipc/signalfuncs.c
+++ b/src/backend/storage/ipc/signalfuncs.c
@@ -34,8 +34,9 @@
* role as the backend being signaled. For "dangerous" signals, an explicit
* check for superuser needs to be done prior to calling this function.
*
- * Returns 0 on success, 1 on general failure, 2 on normal permission error
- * and 3 if the caller needs to be a superuser.
+ * Returns 0 on success, 1 on general failure, 2 on normal permission error,
+ * 3 if the caller needs to be a superuser, and 4 if the caller needs to have
+ * privileges of pg_signal_autovacuum_worker.
*
* In the event of a general failure (return code 1), a warning message will
* be emitted. For permission errors, doing that is the responsibility of
@@ -45,6 +46,7 @@
#define SIGNAL_BACKEND_ERROR 1
#define SIGNAL_BACKEND_NOPERMISSION 2
#define SIGNAL_BACKEND_NOSUPERUSER 3
+#define SIGNAL_BACKEND_NOAUTOVAC 4
static int
pg_signal_backend(int pid, int sig)
{
@@ -77,15 +79,27 @@ pg_signal_backend(int pid, int sig)
/*
* Only allow superusers to signal superuser-owned backends. Any process
* not advertising a role might have the importance of a superuser-owned
- * backend, so treat it that way.
+ * backend, so treat it that way. As an exception, we allow roles with
+ * privileges of pg_signal_autovacuum_worker to signal autovacuum workers
+ * (which do not advertise a role).
+ *
+ * Otherwise, users can signal backends for roles they have privileges of.
*/
- if ((!OidIsValid(proc->roleId) || superuser_arg(proc->roleId)) &&
- !superuser())
- return SIGNAL_BACKEND_NOSUPERUSER;
+ if (!OidIsValid(proc->roleId) || superuser_arg(proc->roleId))
+ {
+ ProcNumber procNumber = GetNumberFromPGProc(proc);
+ PgBackendStatus *procStatus = pgstat_get_beentry_by_proc_number(procNumber);
- /* Users can signal backends they have role membership in. */
- if (!has_privs_of_role(GetUserId(), proc->roleId) &&
- !has_privs_of_role(GetUserId(), ROLE_PG_SIGNAL_BACKEND))
+ if (procStatus && procStatus->st_backendType == B_AUTOVAC_WORKER)
+ {
+ if (!has_privs_of_role(GetUserId(), ROLE_PG_SIGNAL_AUTOVACUUM_WORKER))
+ return SIGNAL_BACKEND_NOAUTOVAC;
+ }
+ else if (!superuser())
+ return SIGNAL_BACKEND_NOSUPERUSER;
+ }
+ else if (!has_privs_of_role(GetUserId(), proc->roleId) &&
+ !has_privs_of_role(GetUserId(), ROLE_PG_SIGNAL_BACKEND))
return SIGNAL_BACKEND_NOPERMISSION;
/*
@@ -130,6 +144,13 @@ pg_cancel_backend(PG_FUNCTION_ARGS)
errdetail("Only roles with the %s attribute may cancel queries of roles with the %s attribute.",
"SUPERUSER", "SUPERUSER")));
+ if (r == SIGNAL_BACKEND_NOAUTOVAC)
+ ereport(ERROR,
+ (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+ errmsg("permission denied to cancel query"),
+ errdetail("Only roles with privileges of the \"%s\" role may cancel autovacuum workers.",
+ "pg_signal_autovacuum_worker")));
+
if (r == SIGNAL_BACKEND_NOPERMISSION)
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
@@ -236,6 +257,13 @@ pg_terminate_backend(PG_FUNCTION_ARGS)
errdetail("Only roles with the %s attribute may terminate processes of roles with the %s attribute.",
"SUPERUSER", "SUPERUSER")));
+ if (r == SIGNAL_BACKEND_NOAUTOVAC)
+ ereport(ERROR,
+ (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+ errmsg("permission denied to terminate process"),
+ errdetail("Only roles with privileges of the \"%s\" role may terminate autovacuum workers.",
+ "pg_signal_autovacuum_worker")));
+
if (r == SIGNAL_BACKEND_NOPERMISSION)
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 4bf79d462ac..06f43c496f3 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -57,6 +57,6 @@
*/
/* yyyymmddN */
-#define CATALOG_VERSION_NO 202407082
+#define CATALOG_VERSION_NO 202407091
#endif
diff --git a/src/include/catalog/pg_authid.dat b/src/include/catalog/pg_authid.dat
index bf00815c14e..0129f67eaaa 100644
--- a/src/include/catalog/pg_authid.dat
+++ b/src/include/catalog/pg_authid.dat
@@ -99,5 +99,10 @@
rolcreaterole => 'f', rolcreatedb => 'f', rolcanlogin => 'f',
rolreplication => 'f', rolbypassrls => 'f', rolconnlimit => '-1',
rolpassword => '_null_', rolvaliduntil => '_null_' },
+{ oid => '8916', oid_symbol => 'ROLE_PG_SIGNAL_AUTOVACUUM_WORKER',
+ rolname => 'pg_signal_autovacuum_worker', rolsuper => 'f', rolinherit => 't',
+ rolcreaterole => 'f', rolcreatedb => 'f', rolcanlogin => 'f',
+ rolreplication => 'f', rolbypassrls => 'f', rolconnlimit => '-1',
+ rolpassword => '_null_', rolvaliduntil => '_null_' },
]