Hi,
On 4.4.7, since switching to db_mode 2 for usrloc with the following settings:
modparam("usrloc", "db_mode", 2) modparam("usrloc", "timer_procs", 2) modparam("usrloc", "skip_remote_socket", 1) modparam("usrloc", "timer_interval", 30) modparam("usrloc", "matching_mode", 0)
I seem to run into a situation where, despite starting from zero local registrations and an empty DB `location` table, out of ~1700 registrations visible in the runtime usrloc table, about 60-80 never make it into the database.
This is because they're being continuously UPDATE'd rather than INSERT'd, so there is some presumption that they should already be in the Postgres database. But they're not.
This gap seems to very slowly grow over time.
I understand that this option is intended to deal with a scenario like that:
https://kamailio.org/docs/modules/5.3.x/modules/usrloc.html#usrloc.p.db_chec...
but the documentation doesn't say it needs to be on for db_mode 2 to work correctly, and it's off by default.
I'm wondering what causes certain registrants to get into this state in the first place, where the registrar presumes that they've already been synced to the DB and only need to be update'd on renewal, where in fact they have not been synced.
Causes I've ruled out:
1) The contacts being ignored due to non-local socket or other invalidation;
2) Contacts being explicitly deleted by an outside process.
Any ideas appreciated!
-- Alex
And another question that goes along with this:
Do I need `db_timer_clean` to make db_mode 2 work as expected?
A reasonable person would conclude from the documentation for `timer_interval` and `db_mode 2` ...
"2 - Write-Back scheme. This is a combination of previous two schemes. All changes are made to memory and database synchronization is done in the timer. The timer deletes all expired contacts and flushes all modified or new contacts to database."
"The module uses a timer to delete expired contacts, synchronize with database and other tasks, that need to be run periodically."
... that deletion of expired contacts is propagated to underlying DB storage (passed through the logic of whichever db_mode) in the form of periodic deletions of expired contacts.
It appears not to be enabled by default. DELETE statements appear to be issued periodically from usrloc even though it's not enabled.
So, what's that setting for? When and why do I need it?
-- Alex
On Fri, Mar 06, 2020 at 12:58:16PM -0500, Alex Balashov wrote:
Hi,
On 4.4.7, since switching to db_mode 2 for usrloc with the following settings:
modparam("usrloc", "db_mode", 2) modparam("usrloc", "timer_procs", 2) modparam("usrloc", "skip_remote_socket", 1) modparam("usrloc", "timer_interval", 30) modparam("usrloc", "matching_mode", 0)
I seem to run into a situation where, despite starting from zero local registrations and an empty DB `location` table, out of ~1700 registrations visible in the runtime usrloc table, about 60-80 never make it into the database.
This is because they're being continuously UPDATE'd rather than INSERT'd, so there is some presumption that they should already be in the Postgres database. But they're not.
This gap seems to very slowly grow over time.
I understand that this option is intended to deal with a scenario like that:
https://kamailio.org/docs/modules/5.3.x/modules/usrloc.html#usrloc.p.db_chec...
but the documentation doesn't say it needs to be on for db_mode 2 to work correctly, and it's off by default.
I'm wondering what causes certain registrants to get into this state in the first place, where the registrar presumes that they've already been synced to the DB and only need to be update'd on renewal, where in fact they have not been synced.
Causes I've ruled out:
- The contacts being ignored due to non-local socket or other
invalidation;
- Contacts being explicitly deleted by an outside process.
Any ideas appreciated!
-- Alex
-- Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Hi,
There are multiple scenarios and possibilities for this behavior, please check,
1. What kind of sip endpoints you have? Any TCP based transport e.g. TLS or WSS endpoint? Are they mobile apps (especially iOS devices) with push notification and "backgrounding" support?
2. How many distinct SIP re-registers (SQL Updates) you have at a time? Please also check if they are lower then actual endpoints.
Thank you.
On Fri, Mar 6, 2020 at 7:32 PM Alex Balashov abalashov@evaristesys.com wrote:
And another question that goes along with this:
Do I need `db_timer_clean` to make db_mode 2 work as expected?
A reasonable person would conclude from the documentation for `timer_interval` and `db_mode 2` ...
"2 - Write-Back scheme. This is a combination of previous two schemes. All changes are made to memory and database synchronization is done in the timer. The timer deletes all expired contacts and flushes all modified or new contacts to database."
"The module uses a timer to delete expired contacts, synchronize with database and other tasks, that need to be run periodically."
... that deletion of expired contacts is propagated to underlying DB storage (passed through the logic of whichever db_mode) in the form of periodic deletions of expired contacts.
It appears not to be enabled by default. DELETE statements appear to be issued periodically from usrloc even though it's not enabled.
So, what's that setting for? When and why do I need it?
-- Alex
On Fri, Mar 06, 2020 at 12:58:16PM -0500, Alex Balashov wrote:
Hi,
On 4.4.7, since switching to db_mode 2 for usrloc with the following
settings:
modparam("usrloc", "db_mode", 2) modparam("usrloc", "timer_procs", 2) modparam("usrloc", "skip_remote_socket", 1) modparam("usrloc", "timer_interval", 30) modparam("usrloc", "matching_mode", 0)
I seem to run into a situation where, despite starting from zero local registrations and an empty DB `location` table, out of ~1700 registrations visible in the runtime usrloc table, about 60-80 never make it into the database.
This is because they're being continuously UPDATE'd rather than INSERT'd, so there is some presumption that they should already be in the Postgres database. But they're not.
This gap seems to very slowly grow over time.
I understand that this option is intended to deal with a scenario like that:
https://kamailio.org/docs/modules/5.3.x/modules/usrloc.html#usrloc.p.db_chec...
but the documentation doesn't say it needs to be on for db_mode 2 to work correctly, and it's off by default.
I'm wondering what causes certain registrants to get into this state in the first place, where the registrar presumes that they've already been synced to the DB and only need to be update'd on renewal, where in fact they have not been synced.
Causes I've ruled out:
- The contacts being ignored due to non-local socket or other
invalidation;
- Contacts being explicitly deleted by an outside process.
Any ideas appreciated!
-- Alex
-- Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
-- Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Hi,
The endpoints are just plain UDP.
I don’t have an answer on #2, except to say that the majority of endpoints are behind NAT and therefore that their re-registration interval is quite low—perhaps 60-120 seconds.
I don’t have a great knowledge of Kamailio modules’ startup sequence, but my suspicion is that a certain number of registrations might be flooding into SIP workers that are already available and responsive while the database connections are still being initialised, but before they are available. Or perhaps some other race condition along those general lines.
That still leaves some questions surrounding the purpose and necessity of various settings, however.
— Alex
— Sent from mobile, with due apologies for brevity and errors.
On Mar 7, 2020, at 1:28 AM, M S shaheryarkh@gmail.com wrote:
Hi,
There are multiple scenarios and possibilities for this behavior, please check,
What kind of sip endpoints you have? Any TCP based transport e.g. TLS or WSS endpoint? Are they mobile apps (especially iOS devices) with push notification and "backgrounding" support?
How many distinct SIP re-registers (SQL Updates) you have at a time? Please also check if they are lower then actual endpoints.
Thank you.
On Fri, Mar 6, 2020 at 7:32 PM Alex Balashov abalashov@evaristesys.com wrote: And another question that goes along with this:
Do I need `db_timer_clean` to make db_mode 2 work as expected?
A reasonable person would conclude from the documentation for `timer_interval` and `db_mode 2` ...
"2 - Write-Back scheme. This is a combination of previous two schemes. All changes are made to memory and database synchronization is done in the timer. The timer deletes all expired contacts and flushes all modified or new contacts to database."
"The module uses a timer to delete expired contacts, synchronize with database and other tasks, that need to be run periodically."
... that deletion of expired contacts is propagated to underlying DB storage (passed through the logic of whichever db_mode) in the form of periodic deletions of expired contacts.
It appears not to be enabled by default. DELETE statements appear to be issued periodically from usrloc even though it's not enabled.
So, what's that setting for? When and why do I need it?
-- Alex
On Fri, Mar 06, 2020 at 12:58:16PM -0500, Alex Balashov wrote:
Hi,
On 4.4.7, since switching to db_mode 2 for usrloc with the following settings:
modparam("usrloc", "db_mode", 2) modparam("usrloc", "timer_procs", 2) modparam("usrloc", "skip_remote_socket", 1) modparam("usrloc", "timer_interval", 30) modparam("usrloc", "matching_mode", 0)
I seem to run into a situation where, despite starting from zero local registrations and an empty DB `location` table, out of ~1700 registrations visible in the runtime usrloc table, about 60-80 never make it into the database.
This is because they're being continuously UPDATE'd rather than INSERT'd, so there is some presumption that they should already be in the Postgres database. But they're not.
This gap seems to very slowly grow over time.
I understand that this option is intended to deal with a scenario like that:
https://kamailio.org/docs/modules/5.3.x/modules/usrloc.html#usrloc.p.db_chec...
but the documentation doesn't say it needs to be on for db_mode 2 to work correctly, and it's off by default.
I'm wondering what causes certain registrants to get into this state in the first place, where the registrar presumes that they've already been synced to the DB and only need to be update'd on renewal, where in fact they have not been synced.
Causes I've ruled out:
- The contacts being ignored due to non-local socket or other
invalidation;
- Contacts being explicitly deleted by an outside process.
Any ideas appreciated!
-- Alex
-- Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
-- Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Well, since you have UDP endpoints, so most likely they are fixed endpoint e.g. desk phones which almost never have network change. I know i am assuming a lot here but this seems like a corporate network with hardware router/firewall. The hardware routers usually have UDP NAT mapping allocation interval of 25 seconds (e.g. CISCO ASA 55xx). It means that if there is no UDP traffic on NATted connection for 25 seconds then router will close the NAT mapping and SIP client will have to request for another one when it sends next register after 60 seconds.
Also, if sip endpoint registers for 60 seconds then LCM(60, 25) = 300 seconds i.e. there will be one sip re-register (SQL UPDATE) after every 5 registers (SQL INSERT) for same endpoint due to matching_mode 0 (Contact Only). If the SIP register interval is 120 seconds then LCM(120, 25) = 600 seconds, i.e. 1 in 12 will be SQL UPDATE. Now, since you have timer_interval of 30 seconds [i.e. LCM(300, 30) = 300 and LCM(600, 30) = 600] so depending on sorting order of usrloc records fetched from db, the SQL UPDATE is likely to fail (i.e. have no matching db record) and kept in memory till next clean up.
Here are a few recommendations.
1. Enable UDP keepalives with very short intervals, e.g. 10 seconds to keep NAT mapping at client side router open indefinitely. Set more then one dedicated NAT ping processes if you have high number of active users (roughly 1 process per 1K active users at peak times).
https://kamailio.org/docs/modules/4.4.x/modules/nathelper.html#nathelper.p.n...
2. Enable db_check_update module option, to force insert the record in db, this will convert orphan SQL Updates to SQL Inserts.
https://kamailio.org/docs/modules/4.4.x/modules/usrloc.html#usrloc.p.db_chec...
Or alternatively, use db_update_as_insert (somewhat more efficient),
https://kamailio.org/docs/modules/4.4.x/modules/usrloc.html#usrloc.p.db_upda...
3. Enable db_clean_timer, it is kind of required option for db mode 2, especially if sip endpoint disconnects from network and its network changes or kamailio restarts, all so often.
https://kamailio.org/docs/modules/4.4.x/modules/usrloc.html#usrloc.p.db_time...
4. Also optionally, consider using matching_mode 3 (Call-ID Only), this solves a lot of duplication problems in SIP re-registration and SIP forking over UDP transport.
https://kamailio.org/docs/modules/4.4.x/modules/usrloc.html#usrloc.p.matchin...
5. Optionally, for fixed sip endpoints, it is better to set larger SIP expiry when possible. I recommend using minimum 300 seconds and maximum 600 seconds.
Hope this help.
On Sat, Mar 7, 2020 at 7:37 AM Alex Balashov abalashov@evaristesys.com wrote:
Hi,
The endpoints are just plain UDP.
I don’t have an answer on #2, except to say that the majority of endpoints are behind NAT and therefore that their re-registration interval is quite low—perhaps 60-120 seconds.
I don’t have a great knowledge of Kamailio modules’ startup sequence, but my suspicion is that a certain number of registrations might be flooding into SIP workers that are already available and responsive while the database connections are still being initialised, but before they are available. Or perhaps some other race condition along those general lines.
That still leaves some questions surrounding the purpose and necessity of various settings, however.
— Alex
— Sent from mobile, with due apologies for brevity and errors.
On Mar 7, 2020, at 1:28 AM, M S shaheryarkh@gmail.com wrote:
Hi,
There are multiple scenarios and possibilities for this behavior, please check,
- What kind of sip endpoints you have? Any TCP based transport e.g. TLS
or WSS endpoint? Are they mobile apps (especially iOS devices) with push notification and "backgrounding" support?
- How many distinct SIP re-registers (SQL Updates) you have at a time?
Please also check if they are lower then actual endpoints.
Thank you.
On Fri, Mar 6, 2020 at 7:32 PM Alex Balashov abalashov@evaristesys.com wrote:
And another question that goes along with this:
Do I need `db_timer_clean` to make db_mode 2 work as expected?
A reasonable person would conclude from the documentation for `timer_interval` and `db_mode 2` ...
"2 - Write-Back scheme. This is a combination of previous two schemes. All changes are made to memory and database synchronization is done in the timer. The timer deletes all expired contacts and flushes all modified or new contacts to database."
"The module uses a timer to delete expired contacts, synchronize with database and other tasks, that need to be run periodically."
... that deletion of expired contacts is propagated to underlying DB storage (passed through the logic of whichever db_mode) in the form of periodic deletions of expired contacts.
It appears not to be enabled by default. DELETE statements appear to be issued periodically from usrloc even though it's not enabled.
So, what's that setting for? When and why do I need it?
-- Alex
On Fri, Mar 06, 2020 at 12:58:16PM -0500, Alex Balashov wrote:
Hi,
On 4.4.7, since switching to db_mode 2 for usrloc with the following
settings:
modparam("usrloc", "db_mode", 2) modparam("usrloc", "timer_procs", 2) modparam("usrloc", "skip_remote_socket", 1) modparam("usrloc", "timer_interval", 30) modparam("usrloc", "matching_mode", 0)
I seem to run into a situation where, despite starting from zero local registrations and an empty DB `location` table, out of ~1700 registrations visible in the runtime usrloc table, about 60-80 never make it into the database.
This is because they're being continuously UPDATE'd rather than INSERT'd, so there is some presumption that they should already be in the Postgres database. But they're not.
This gap seems to very slowly grow over time.
I understand that this option is intended to deal with a scenario like that:
https://kamailio.org/docs/modules/5.3.x/modules/usrloc.html#usrloc.p.db_chec...
but the documentation doesn't say it needs to be on for db_mode 2 to work correctly, and it's off by default.
I'm wondering what causes certain registrants to get into this state in the first place, where the registrar presumes that they've already been synced to the DB and only need to be update'd on renewal, where in fact they have not been synced.
Causes I've ruled out:
- The contacts being ignored due to non-local socket or other
invalidation;
- Contacts being explicitly deleted by an outside process.
Any ideas appreciated!
-- Alex
-- Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
-- Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Hi Alex,
the db_timer_clean is just an additional mechanism to clean-up expired records. Like if you get some errors from time to time in the DB connection, and some deletes are not correctly processed on the DB. Then some stale records should be left in the DB, and you can use this one to clean up.
Normally it should be not necessary, as Kamailio will synchronize it just by the normal timer. From the source:
/*! * \brief Write-back timer, used for WRITE_BACK db_mode * * Write-back timer, used for WRITE_BACK db_mode. Process * all contacts from the record, delete expired ones from the DB. * Furthermore it updates changed contacts, and also insert new * ones in the DB. * \param _r processed record */ static inline void wb_timer(urecord_t* _r) {..}
About the first question, why some registrations are missing in the DB - this needs to be investigated more closely. As a workaround you could try (as already suggested) to use the INSERT instead of UPDATE module parameter, e.g. with db_check_update.
Cheers,
Henning
Hi Henning,
Yes, the db_check_update approach provides an adequate solution. I already explored that before making this post.
My interest in that issue is insofar as:
1) How do registrants come to go missing from the DB sync, if assured to be starting from 0?
2) If this is a quality that is innate to how db_mode 2 works, shouldn’t db_check_update be on by default, and/or shouldn’t the documentation reflect that db_check_update is a necessary or best practice alongside db_mode 2?
— Alex
— Sent from my iPad
On Mar 7, 2020, at 3:19 PM, Henning Westerholt hw@skalatan.de wrote:
Hi Alex,
the db_timer_clean is just an additional mechanism to clean-up expired records. Like if you get some errors from time to time in the DB connection, and some deletes are not correctly processed on the DB. Then some stale records should be left in the DB, and you can use this one to clean up.
Normally it should be not necessary, as Kamailio will synchronize it just by the normal timer. From the source:
/*!
- \brief Write-back timer, used for WRITE_BACK db_mode
- Write-back timer, used for WRITE_BACK db_mode. Process
- all contacts from the record, delete expired ones from the DB.
- Furthermore it updates changed contacts, and also insert new
- ones in the DB.
- \param _r processed record
*/ static inline void wb_timer(urecord_t* _r) {..}
About the first question, why some registrations are missing in the DB - this needs to be investigated more closely. As a workaround you could try (as already suggested) to use the INSERT instead of UPDATE module parameter, e.g. with db_check_update.
Cheers,
Henning
-- Henning Westerholt – https://skalatan.de/blog/ Kamailio services – https://gilawa.com
-----Original Message----- From: sr-users sr-users-bounces@lists.kamailio.org On Behalf Of Alex Balashov Sent: Friday, March 6, 2020 7:31 PM To: sr-users@lists.kamailio.org Subject: Re: [SR-Users] usrloc db_mode 2 and dropped contacts
And another question that goes along with this:
Do I need `db_timer_clean` to make db_mode 2 work as expected?
A reasonable person would conclude from the documentation for `timer_interval` and `db_mode 2` ...
"2 - Write-Back scheme. This is a combination of previous two schemes. All changes are made to memory and database synchronization is done in the timer. The timer deletes all expired contacts and flushes all modified or new contacts to database."
"The module uses a timer to delete expired contacts, synchronize with database and other tasks, that need to be run periodically."
... that deletion of expired contacts is propagated to underlying DB storage (passed through the logic of whichever db_mode) in the form of periodic deletions of expired contacts.
It appears not to be enabled by default. DELETE statements appear to be issued periodically from usrloc even though it's not enabled.
So, what's that setting for? When and why do I need it?
-- Alex
On Fri, Mar 06, 2020 at 12:58:16PM -0500, Alex Balashov wrote:
Hi,
On 4.4.7, since switching to db_mode 2 for usrloc with the following settings:
modparam("usrloc", "db_mode", 2) modparam("usrloc", "timer_procs", 2) modparam("usrloc", "skip_remote_socket", 1) modparam("usrloc", "timer_interval", 30) modparam("usrloc", "matching_mode", 0)
I seem to run into a situation where, despite starting from zero local registrations and an empty DB `location` table, out of ~1700 registrations visible in the runtime usrloc table, about 60-80 never make it into the database.
This is because they're being continuously UPDATE'd rather than INSERT'd, so there is some presumption that they should already be in the Postgres database. But they're not.
This gap seems to very slowly grow over time.
I understand that this option is intended to deal with a scenario like that:
https://kamailio.org/docs/modules/5.3.x/modules/usrloc.html#usrloc.p.d b_check_update
but the documentation doesn't say it needs to be on for db_mode 2 to work correctly, and it's off by default.
I'm wondering what causes certain registrants to get into this state in the first place, where the registrar presumes that they've already been synced to the DB and only need to be update'd on renewal, where in fact they have not been synced.
Causes I've ruled out:
- The contacts being ignored due to non-local socket or other
invalidation;
- Contacts being explicitly deleted by an outside process.
Any ideas appreciated!
-- Alex
-- Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
-- Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Hello,
On 07.03.20 21:29, Alex Balashov wrote:
Hi Henning,
Yes, the db_check_update approach provides an adequate solution. I already explored that before making this post.
My interest in that issue is insofar as:
- How do registrants come to go missing from the DB sync, if assured to be starting from 0?
this can happen if there is some interruption on db connection, like db server restart or freeze due to some locking done by external lengthy sync/search operations. Normally there should be some error messages in the syslog, either for kamailio or for db server.
As you run a rather old version there (I understand 4.4.x), it may also be one of the old issues related to generation of ruid, iirc, at some point there were some conflicts, but I do not recall when (what specific cases ) and for what versions. Lately, for quite a few years, all was smooth from code point of view, only disruptions to db connectivity or external factors could end up here.
One more thing to take in consideration is firewall (+conntrack kernel mods)/enterprise limits systems (like selinux) -- if you end up in high rates of traffic, I notices that in some cases, without spotting a clear pattern, those systems fire up and close connections or drop traffic.
Cheers, Daniel
- If this is a quality that is innate to how db_mode 2 works, shouldn’t db_check_update be on by default, and/or shouldn’t the documentation reflect that db_check_update is a necessary or best practice alongside db_mode 2?
— Alex
— Sent from my iPad
On Mar 7, 2020, at 3:19 PM, Henning Westerholt hw@skalatan.de wrote:
Hi Alex,
the db_timer_clean is just an additional mechanism to clean-up expired records. Like if you get some errors from time to time in the DB connection, and some deletes are not correctly processed on the DB. Then some stale records should be left in the DB, and you can use this one to clean up.
Normally it should be not necessary, as Kamailio will synchronize it just by the normal timer. From the source:
/*!
- \brief Write-back timer, used for WRITE_BACK db_mode
- Write-back timer, used for WRITE_BACK db_mode. Process
- all contacts from the record, delete expired ones from the DB.
- Furthermore it updates changed contacts, and also insert new
- ones in the DB.
- \param _r processed record
*/ static inline void wb_timer(urecord_t* _r) {..}
About the first question, why some registrations are missing in the DB - this needs to be investigated more closely. As a workaround you could try (as already suggested) to use the INSERT instead of UPDATE module parameter, e.g. with db_check_update.
Cheers,
Henning
-- Henning Westerholt – https://skalatan.de/blog/ Kamailio services – https://gilawa.com
-----Original Message----- From: sr-users sr-users-bounces@lists.kamailio.org On Behalf Of Alex Balashov Sent: Friday, March 6, 2020 7:31 PM To: sr-users@lists.kamailio.org Subject: Re: [SR-Users] usrloc db_mode 2 and dropped contacts
And another question that goes along with this:
Do I need `db_timer_clean` to make db_mode 2 work as expected?
A reasonable person would conclude from the documentation for `timer_interval` and `db_mode 2` ...
"2 - Write-Back scheme. This is a combination of previous two schemes. All changes are made to memory and database synchronization is done in the timer. The timer deletes all expired contacts and flushes all modified or new contacts to database."
"The module uses a timer to delete expired contacts, synchronize with database and other tasks, that need to be run periodically."
... that deletion of expired contacts is propagated to underlying DB storage (passed through the logic of whichever db_mode) in the form of periodic deletions of expired contacts.
It appears not to be enabled by default. DELETE statements appear to be issued periodically from usrloc even though it's not enabled.
So, what's that setting for? When and why do I need it?
-- Alex
On Fri, Mar 06, 2020 at 12:58:16PM -0500, Alex Balashov wrote:
Hi,
On 4.4.7, since switching to db_mode 2 for usrloc with the following settings:
modparam("usrloc", "db_mode", 2) modparam("usrloc", "timer_procs", 2) modparam("usrloc", "skip_remote_socket", 1) modparam("usrloc", "timer_interval", 30) modparam("usrloc", "matching_mode", 0)
I seem to run into a situation where, despite starting from zero local registrations and an empty DB `location` table, out of ~1700 registrations visible in the runtime usrloc table, about 60-80 never make it into the database.
This is because they're being continuously UPDATE'd rather than INSERT'd, so there is some presumption that they should already be in the Postgres database. But they're not.
This gap seems to very slowly grow over time.
I understand that this option is intended to deal with a scenario like that:
https://kamailio.org/docs/modules/5.3.x/modules/usrloc.html#usrloc.p.d b_check_update
but the documentation doesn't say it needs to be on for db_mode 2 to work correctly, and it's off by default.
I'm wondering what causes certain registrants to get into this state in the first place, where the registrar presumes that they've already been synced to the DB and only need to be update'd on renewal, where in fact they have not been synced.
Causes I've ruled out:
- The contacts being ignored due to non-local socket or other
invalidation;
- Contacts being explicitly deleted by an outside process.
Any ideas appreciated!
-- Alex
-- Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
-- Alex Balashov | Principal | Evariste Systems LLC
Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
Hi Alex,
about the second question - a bit hard to tell. I remember that some big deployments used patches with a similar effect already many years ago. On the other hand, there have been not much reports on list or tracker on these problems in the past.
The documentation can be always improved, of course. Maybe something in the way to support against interruptions or similar events. About to make db_check_update the default - it has no effect on DBs that do not support the necessary affected_rows API function. But the functionality is rather small, and the performance impact negligible, so it sounds like a good idea. Would be probably good to ask again briefly on sr-users, if there are other opinion on this step.
Cheers,
Henning
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Alex Balashov -
Daniel-Constantin Mierla -
Henning Westerholt -
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