On 4/6/17 15:01, Peter Eisentraut wrote:
> On 2/15/17 11:19, Peter Eisentraut wrote:
>> So I would like to have a background worker limit per user, as you
>> allude to. Attached is a patch that implements a GUC setting
>> max_worker_processes_per_user.
>>
>> Besides the uses for background sessions, but it can also be useful for
>> parallel workers, logical replication apply workers, or things like
>> third-party partitioning extensions.
>
> Given that background sessions have been postponed, is there still
> interest in this separate from that? It would be useful for per-user
> parallel worker limits, for example.
Here is a slightly updated patch for consideration in the upcoming
commit fest.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
From e99d8ccf9dfd007c054b20e8d10ffb35cfb722b7 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <pete...@gmx.net>
Date: Wed, 23 Aug 2017 19:10:21 -0400
Subject: [PATCH v2] Add max_worker_processes_per_user setting
---
doc/src/sgml/config.sgml | 28 ++++++++++++++++++++++++++++
doc/src/sgml/ref/create_role.sgml | 3 ++-
src/backend/postmaster/bgworker.c | 28 ++++++++++++++++++++++++++++
src/backend/utils/init/globals.c | 1 +
src/backend/utils/misc/guc.c | 12 ++++++++++++
src/include/miscadmin.h | 1 +
6 files changed, 72 insertions(+), 1 deletion(-)
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 2b6255ed95..24f1d13f8a 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -2041,6 +2041,34 @@ <title>Asynchronous Behavior</title>
</listitem>
</varlistentry>
+ <varlistentry id="guc-max-worker-processes-per-user"
xreflabel="max_worker_processes_per_user">
+ <term><varname>max_worker_processes_per_user</varname>
(<type>integer</type>)
+ <indexterm>
+ <primary><varname>max_worker_processes_per_user</> configuration
parameter</primary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ Sets the maximum number of background processes allowed per user. If
+ the setting is -1, then there is no limit. That is also the default.
+ </para>
+
+ <para>
+ Only superusers can change this setting.
+ Unlike <varname>max_worker_processes</varname>, which controls the
+ overall instance limit, this setting can also be changed at run time
+ and can be set differently for different users by
+ using <literal>ALTER ROLE ... SET</literal>.
+ </para>
+
+ <para>
+ This setting is checked at the time the worker process is started
+ using the setting in the session that causes it to start. Changes to
+ the setting will not affect already running workers.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="guc-max-parallel-workers-per-gather"
xreflabel="max_parallel_workers_per_gather">
<term><varname>max_parallel_workers_per_gather</varname>
(<type>integer</type>)
<indexterm>
diff --git a/doc/src/sgml/ref/create_role.sgml
b/doc/src/sgml/ref/create_role.sgml
index 36772b678a..a7c547d907 100644
--- a/doc/src/sgml/ref/create_role.sgml
+++ b/doc/src/sgml/ref/create_role.sgml
@@ -204,7 +204,8 @@ <title>Parameters</title>
the role can make. -1 (the default) means no limit. Note that only
normal connections are counted towards this limit. Neither prepared
transactions nor background worker connections are counted towards
- this limit.
+ this limit (see <xref linkend="guc-max-worker-processes-per-user">
+ for the latter).
</para>
</listitem>
</varlistentry>
diff --git a/src/backend/postmaster/bgworker.c
b/src/backend/postmaster/bgworker.c
index 28af6f0f07..443dcaa4f3 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -79,6 +79,7 @@ typedef struct BackgroundWorkerSlot
bool in_use;
bool terminate;
pid_t pid; /* InvalidPid = not started
yet; 0 = dead */
+ Oid roleid; /* user responsible for
it */
uint64 generation; /* incremented when slot is
recycled */
BackgroundWorker worker;
} BackgroundWorkerSlot;
@@ -976,6 +977,32 @@ RegisterDynamicBackgroundWorker(BackgroundWorker *worker,
return false;
}
+ /*
+ * Check number of used slots for user
+ */
+ if (max_worker_processes_per_user >= 0)
+ {
+ int count = 0;
+
+ for (slotno = 0; slotno < BackgroundWorkerData->total_slots;
++slotno)
+ {
+ BackgroundWorkerSlot *slot =
&BackgroundWorkerData->slot[slotno];
+
+ if (slot->in_use && slot->roleid == GetUserId())
+ count++;
+ }
+
+ if (count > max_worker_processes_per_user)
+ {
+ ereport(LOG,
+
(errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED),
+ errmsg("too many worker processes for
role \"%s\"",
+
GetUserNameFromId(GetUserId(), false))));
+ LWLockRelease(BackgroundWorkerLock);
+ return false;
+ }
+ }
+
/*
* Look for an unused slot. If we find one, grab it.
*/
@@ -987,6 +1014,7 @@ RegisterDynamicBackgroundWorker(BackgroundWorker *worker,
{
memcpy(&slot->worker, worker, sizeof(BackgroundWorker));
slot->pid = InvalidPid; /* indicates not started yet */
+ slot->roleid = GetUserId();
slot->generation++;
slot->terminate = false;
generation = slot->generation;
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 7c09498dc0..fa1b689ae7 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -123,6 +123,7 @@ int replacement_sort_tuples = 150000;
int NBuffers = 1000;
int MaxConnections = 90;
int max_worker_processes = 8;
+int max_worker_processes_per_user = -1;
int max_parallel_workers = 8;
int MaxBackends = 0;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 246fea8693..23dc33bd61 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2506,6 +2506,18 @@ static struct config_int ConfigureNamesInt[] =
check_max_worker_processes, NULL, NULL
},
+ {
+ {"max_worker_processes_per_user",
+ PGC_SUSET,
+ RESOURCES_ASYNCHRONOUS,
+ gettext_noop("Maximum number of concurrent worker
processes per user."),
+ NULL,
+ },
+ &max_worker_processes_per_user,
+ -1, -1, MAX_BACKENDS,
+ NULL, NULL, NULL
+ },
+
{
{"max_logical_replication_workers",
PGC_POSTMASTER,
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index dad98de98d..a9f21cc34b 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -158,6 +158,7 @@ extern PGDLLIMPORT int NBuffers;
extern int MaxBackends;
extern int MaxConnections;
extern int max_worker_processes;
+extern int max_worker_processes_per_user;
extern int max_parallel_workers;
extern PGDLLIMPORT int MyProcPid;
--
2.14.1
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
