<div dir="ltr"><div>Here is the strace result, hope this helps in any way, it takes about 10 minutes for the semaphors to 'go away'...</div><div><br></div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Mon, Jun 2, 2025 at 2:53 PM Tatsuo Ishii <<a href="mailto:ishii@postgresql.org">ishii@postgresql.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">You have 4 pgpool nodes and you issue the queries through one of<br>
pgpools. Suppose you issued the queries through node 0, the "status"<br>
field is only updated on node 0. On other 3 nodes the status remains<br>
"waiting". However the status on all 4 nodes will be synched when the<br>
status becomes "down", or becomes "up" and the former status is<br>
"down".<br>
<br>
> That's where I wonder if this is working properly, because there seem to be<br>
> clients/connections happening, I ran the backend status command this is<br>
> what it showed:<br>
> <br>
> node_id | hostname | port | status | role | select_cnt |<br>
> insert_cnt | update_cnt | delete_cnt | ddl_cnt | other_cnt | panic_cnt |<br>
> fatal_cnt | error_cnt<br>
> <br>
> ---------+------------------------+------+--------+---------+------------+------------+------------+------------+---------+-----------+-----------+-----------+-----------<br>
> <br>
> 0 | db-primarypriv | 5434 | up | primary | 7552 | 47<br>
> | 332 | 27 | 0 | 13678 | 0 | 0 |<br>
> 6<br>
> <br>
> 1 | db-replica1priv | 5434 | up | standby | 6817 | 0<br>
> | 0 | 0 | 0 | 13682 | 0 | 0 |<br>
> 0<br>
> <br>
> 2 | db-replica2priv | 5434 | up | standby | 6514 | 0<br>
> | 0 | 0 | 0 | 13693 | 0 | 0 |<br>
> 1<br>
> <br>
> 3 | db-replica3priv | 5434 | up | standby | 6910 | 0<br>
> | 0 | 0 | 0 | 13679 | 0 | 0 |<br>
> 1<br>
> <br>
> (4 rows)<br>
> <br>
> So plenty of queries supposedly happening on them, but the nodes still show<br>
> status 1. What gives?<br>
> <br>
> <br>
> On Mon, Jun 2, 2025 at 1:43 PM Tatsuo Ishii <<a href="mailto:ishii@postgresql.org" target="_blank">ishii@postgresql.org</a>> wrote:<br>
> <br>
>> > Hi, another thing I noticed - the status of all those nodes in<br>
>> > pcp_node_info seems to be wrong, for example:<br>
>> > $ pcp_node_info -h localhost -p 9898 -U pcpadmin --verbose -n 3<br>
>> > Hostname : db-replica2<br>
>> > Port : 5434<br>
>> > Status : 1<br>
>> > Weight : 0.250000<br>
>> > Status Name : waiting<br>
>> > Backend Status Name : up<br>
>> > Role : standby<br>
>> > Backend Role : standby<br>
>> > Replication Delay : 0<br>
>> > Replication State : streaming<br>
>> > Replication Sync State : async<br>
>> > Last Status Change : 2025-06-02 12:31:46<br>
>><br>
>> Are you saying this is wrong?<br>
>><br>
>> > Status : 1<br>
>><br>
>> Seems normal to me because it just says no client has connected to the<br>
>> pgpool server until now.<br>
>><br>
>> > Do you think this is because of the semaphore problem, or does it suggest<br>
>> > something else completely?<br>
>> ><br>
>> > On Mon, Jun 2, 2025 at 12:59 PM Tatsuo Ishii <<a href="mailto:ishii@postgresql.org" target="_blank">ishii@postgresql.org</a>><br>
>> wrote:<br>
>> ><br>
>> >> > Hi, I changed the pgpool.service file for startup as you said,<br>
>> replaced<br>
>> >> my<br>
>> >> > start with this:<br>
>> >> > ExecStart=strace -f -tt --trace=ipc /usr/sbin/pgpool -f<br>
>> >> > /etc/pgpool2/pgpool.conf $OPTS<br>
>> >> > I'm attaching the log from replica again, but I'm not sure this<br>
>> actually<br>
>> >> > worked (as in, it doesn't look much different, to me at least).<br>
>> >><br>
>> >> Yeah. It seems there's strace output in the log.<br>
>> >> Can you try "-o" of strace, which instructs strace a file name to print<br>
>> >> the output. e.g.<br>
>> >><br>
>> >> ExecStart=strace -f -tt --trace=ipc -o /tmp/strace.out /usr/sbin/pgpool<br>
>> -f<br>
>> >> /etc/pgpool2/pgpool.conf $OPTS<br>
>> >><br>
>> >> > On Mon, Jun 2, 2025 at 11:47 AM Tatsuo Ishii <<a href="mailto:ishii@postgresql.org" target="_blank">ishii@postgresql.org</a>><br>
>> >> wrote:<br>
>> >> ><br>
>> >> >> > Hi,<br>
>> >> >> > I tried the strace as you shown but it didn't really output<br>
>> anything:<br>
>> >> >> ><br>
>> >> >> > $ sudo strace -p 1662563 -f -tt --trace=ipc<br>
>> >> >> > strace: Process 1662563 attached<br>
>> >> >> ><br>
>> >> >> > ^Cstrace: Process 1662563 detached. <--- this is me getting out<br>
>> of<br>
>> >> it,<br>
>> >> >> > since I saw in another window the semaphores were gone already,<br>
>> >> without<br>
>> >> >> > anything outputting here. Unless something's wrong with the<br>
>> syntax of<br>
>> >> >> the<br>
>> >> >> > command, it didn't really output anything. I changed the log line<br>
>> you<br>
>> >> >> > suggested as well.<br>
>> >> >> ><br>
>> >> >> > Also, FYI - I tried to downgrade to a lower (4.3.7) version as it<br>
>> was<br>
>> >> >> > available in my package repository, and the same semaphore version<br>
>> >> >> persists,<br>
>> >> >><br>
>> >> >> Okay. I think you need to start pgpool from strace. I mean, modifiy<br>
>> >> >> pgpool.service from:<br>
>> >> >> ExecStart=/usr/sbin/pgpool -f /etc/pgpool2/pgpool.conf $OPTS<br>
>> >> >> to:<br>
>> >> >> ExecStart=strace -f -tt --trace=ipc /usr/sbin/pgpool -f<br>
>> >> >> /etc/pgpool2/pgpool.conf $OPTS<br>
>> >> >><br>
>> >> >> > On Mon, Jun 2, 2025 at 2:40 AM Tatsuo Ishii <<a href="mailto:ishii@postgresql.org" target="_blank">ishii@postgresql.org</a>><br>
>> >> >> wrote:<br>
>> >> >> ><br>
>> >> >> >> > Hi,<br>
>> >> >> >> > Not sure I can patch the source, as it was installed via apt get<br>
>> >> and<br>
>> >> >> not<br>
>> >> >> >> > compiled from source. If that is doable to a package-built one<br>
>> and<br>
>> >> >> you<br>
>> >> >> >> can<br>
>> >> >> >> > give me some instructions, I can certainly try.<br>
>> >> >> >><br>
>> >> >> >> Unfortunately I'm not familiar with debian packaging.<br>
>> >> >> >><br>
>> >> >> >> > As for the pgpool log, I'm attaching it, hopefully it will go<br>
>> >> through,<br>
>> >> >> >> it's<br>
>> >> >> >> > about 5mb as I enabled higher debug options.<br>
>> >> >> >><br>
>> >> >> >> It was sent as a direct mail to me. Not sure who/what removed the<br>
>> >> >> >> semaphore. I observe following from the log anyway:<br>
>> >> >> >><br>
>> >> >> >> - pgpool started on 16:10:21. At that time the semaphore<br>
>> definitely<br>
>> >> >> >> existed.<br>
>> >> >> >> - Until 16:15:13, everything worked great.<br>
>> >> >> >> - On 16:15:23, the problem started.<br>
>> >> >> >><br>
>> >> >> >> So it seems the semaphore was removed by someone between 16:15:13<br>
>> and<br>
>> >> >> >> 16:15:23.<br>
>> >> >> >><br>
>> >> >> >> Unfortunately the removal of semaphore was not recorded in the<br>
>> log.<br>
>> >> To<br>
>> >> >> >> determine who removed the semaphore, can you please attach strace<br>
>> to<br>
>> >> >> >> pgpool main and share the log? This time debug log is not<br>
>> necessary.<br>
>> >> >> >><br>
>> >> >> >> - Find the pgpool parent process pid (in the debug log it was<br>
>> >> 1483510)<br>
>> >> >> >> - Become root (attaching strace usually requires root privilege)<br>
>> >> >> >> - Attach strace to the process $pid<br>
>> >> >> >><br>
>> >> >> >> strace -p $pid -f -tt --trace=ipc<br>
>> >> >> >><br>
>> >> >> >> -f: (follow the child process of pgpool main)<br>
>> >> >> >> -tt: add timestamp with milliseconds<br>
>> >> >> >> --trace=ipc: limit the tracing system call to ipc to reduce the<br>
>> log<br>
>> >> >> >><br>
>> >> >> >> BTW, I recommend yo to set log_line_prefix to something like this<br>
>> so<br>
>> >> >> >> that you can take milliseconds log (%m) and process application<br>
>> name<br>
>> >> >> >> (%a). They are usable in 4.6.<br>
>> >> >> >><br>
>> >> >> >> log_line_prefix = '%m: %a pid %p: '<br>
>> >> >> >><br>
>> >> >> >> > On Sun, Jun 1, 2025 at 4:20 PM Tatsuo Ishii <<br>
>> <a href="mailto:ishii@postgresql.org" target="_blank">ishii@postgresql.org</a>><br>
>> >> >> >> wrote:<br>
>> >> >> >> ><br>
>> >> >> >> >> > To your points/questions:<br>
>> >> >> >> >> > 1) version is 4.6.1 - the source I'm using (via apt get)<br>
>> doesn't<br>
>> >> >> have<br>
>> >> >> >> >> 4.6.2<br>
>> >> >> >> >> > yet<br>
>> >> >> >> >><br>
>> >> >> >> >> Ok.<br>
>> >> >> >> >><br>
>> >> >> >> >> > 2) ipcs -s shows... nothing, literally. Checked all nodes,<br>
>> i.e.<br>
>> >> >> >> >> ><br>
>> >> >> >> >> > postgres@db-replica3:~$ ipcs -s<br>
>> >> >> >> >> ><br>
>> >> >> >> >> > ------ Semaphore Arrays --------<br>
>> >> >> >> >> > key semid owner perms nsems<br>
>> >> >> >> >> ><br>
>> >> >> >> >> > Also, it kinda seems like "failed to unlock semaphore" shows<br>
>> >> during<br>
>> >> >> >> >> startup<br>
>> >> >> >> >> > of pgpool and while it's running, but maybe I'm not reading<br>
>> the<br>
>> >> log<br>
>> >> >> >> >> > properly.<br>
>> >> >> >> >><br>
>> >> >> >> >> So pgpool lost semaphore soon after starting. Can you share<br>
>> full<br>
>> >> >> >> >> pgpool log before "failed to unlock semaphore" appears?<br>
>> >> >> >> >><br>
>> >> >> >> >> > 3) regarding heartbeats, my pgpool.conf has it roughly like<br>
>> >> this:<br>
>> >> >> >> >> ><br>
>> >> >> >> >> > heartbeat_hostname0 = 'db-primary-priv'<br>
>> >> >> >> >> > heartbeat_port0 = 9694<br>
>> >> >> >> >> > heartbeat_device0 = ''<br>
>> >> >> >> >> ><br>
>> >> >> >> >> > heartbeat_hostname1 = 'db-replica1-priv'<br>
>> >> >> >> >> > heartbeat_port1 = 9694<br>
>> >> >> >> >> > heartbeat_device1 = ''<br>
>> >> >> >> >> ><br>
>> >> >> >> >> > heartbeat_hostname2 = 'db-replica2-priv'<br>
>> >> >> >> >> > heartbeat_port2 = 9694<br>
>> >> >> >> >> > heartbeat_device2 = ''<br>
>> >> >> >> >> ><br>
>> >> >> >> >> > heartbeat_hostname3 = 'db-replica3-priv'<br>
>> >> >> >> >> > heartbeat_port3 = 9694<br>
>> >> >> >> >> > heartbeat_device3 = ''<br>
>> >> >> >> >><br>
>> >> >> >> >> Looks normal.<br>
>> >> >> >> >><br>
>> >> >> >> >> I have checked the pgpool source code and found suspicious<br>
>> >> >> >> >> code. before 4.6, pgpool heartbeart receiver process binds to<br>
>> any<br>
>> >> >> >> >> address on the host. However from 4.6 pgpool binds to only loop<br>
>> >> back<br>
>> >> >> >> >> address, which is plain wrong. Is it possible for you to patch<br>
>> the<br>
>> >> >> >> >> pgpool source code and build pgpool binary?<br>
>> >> >> >> >><br>
>> >> >> >> >> > So it seems likely that the inability to lock/unlock<br>
>> semaphores<br>
>> >> is<br>
>> >> >> the<br>
>> >> >> >> >> > problem, question is why and how do I resolve it? :(<br>
>> >> >> >> >><br>
>> >> >> >> >> Currently I have no idea. That's why I am requesting the pgpool<br>
>> >> log.<br>
>> >> >> >> >><br>
>> >> >> >> >> > I'll c/p parts of my pgpool.service file as well, in case you<br>
>> >> may<br>
>> >> >> see<br>
>> >> >> >> >> > something 'off' in it?<br>
>> >> >> >> >> ><br>
>> >> >> >> >> ><br>
>> >> >> >> >> > [Service]<br>
>> >> >> >> >> > User=postgres<br>
>> >> >> >> >> > Group=postgres<br>
>> >> >> >> >> ><br>
>> >> >> >> >> > EnvironmentFile=-/etc/default/pgpool2<br>
>> >> >> >> >> ><br>
>> >> >> >> >> > ExecStart=/usr/sbin/pgpool -f /etc/pgpool2/pgpool.conf $OPTS<br>
>> >> >> >> >> > ExecStop=/usr/sbin/pgpool -f /etc/pgpool2/pgpool.conf<br>
>> $STOP_OPTS<br>
>> >> >> stop<br>
>> >> >> >> >> > ExecReload=/usr/sbin/pgpool -f /etc/pgpool2/pgpool.conf<br>
>> reload<br>
>> >> >> >> >> > LimitNOFILE=65536:65536<br>
>> >> >> >> >> > LimitNPROC=16384:16384<br>
>> >> >> >> >> > LimitSTACK=10485760:33554432<br>
>> >> >> >> >> > LimitMEMLOCK=infinity<br>
>> >> >> >> >> > LimitDATA=infinity<br>
>> >> >> >> >> ><br>
>> >> >> >> >> ><br>
>> >> >> >> >> > Thanks in advance.<br>
>> >> >> >> >> ><br>
>> >> >> >> >> > On Sun, Jun 1, 2025 at 2:06 PM Tatsuo Ishii <<br>
>> >> <a href="mailto:ishii@postgresql.org" target="_blank">ishii@postgresql.org</a>><br>
>> >> >> >> >> wrote:<br>
>> >> >> >> >> ><br>
>> >> >> >> >> >> > Hi,<br>
>> >> >> >> >> >> > So long story short, I'm migrating a PG13 cluster from<br>
>> RHEL<br>
>> >> to<br>
>> >> >> >> Ubuntu<br>
>> >> >> >> >> >> > 24.04. In the process, the pgpool version is also being<br>
>> >> >> upgraded to<br>
>> >> >> >> >> 4.6<br>
>> >> >> >> >> >> > (from 4.2).<br>
>> >> >> >> >> >><br>
>> >> >> >> >> >> What is the exact version of 4.6? I am asking because 4.6.0<br>
>> has<br>
>> >> >> >> >> >> vulnerability.<br>
>> >> >> >> >> >><br>
>> >> >> >> >> >><br>
>> >> >> >> >><br>
>> >> >> >><br>
>> >> >><br>
>> >><br>
>> <a href="https://pgpool.net/mediawiki/index.php/Main_Page#Pgpool-II_4.6.1.2C_4.5.7.2C_4.4.12.2C_4.3.15_and_4.2.22_officially_released_.282025.2F05.2F15.29" rel="noreferrer" target="_blank">https://pgpool.net/mediawiki/index.php/Main_Page#Pgpool-II_4.6.1.2C_4.5.7.2C_4.4.12.2C_4.3.15_and_4.2.22_officially_released_.282025.2F05.2F15.29</a><br>
>> >> >> >> >> >><br>
>> >> >> >> >> >> Also 4.6.1 (and 4.6.0) have an issue with IPv6.<br>
>> >> >> >> >> >><br>
>> <a href="https://www.pgpool.net/docs/latest/en/html/release-4-6-2.html" rel="noreferrer" target="_blank">https://www.pgpool.net/docs/latest/en/html/release-4-6-2.html</a><br>
>> >> >> >> >> >><br>
>> >> >> >> >> >> If possible, I recommend to upgrade to 4.6.2.<br>
>> >> >> >> >> >><br>
>> >> >> >> >> >> > There is also repmgr running on this 4 node cluster, 1<br>
>> >> primary<br>
>> >> >> >> >> >> > and 3 replicas.<br>
>> >> >> >> >> >><br>
>> >> >> >> >> >> I am not famililar with repmgr, and I ignore this part.<br>
>> >> >> >> >> >><br>
>> >> >> >> >> >> > All the migration seems to have completed successfully,<br>
>> >> >> >> >> >> > but I've ran into a weird problem with pgpool. I have<br>
>> quite<br>
>> >> a<br>
>> >> >> few<br>
>> >> >> >> >> errors<br>
>> >> >> >> >> >> > that look like the below entries, and it seems to "come<br>
>> and<br>
>> >> go"<br>
>> >> >> >> when<br>
>> >> >> >> >> >> > checking pgpool log. The process itself, seems to work (I<br>
>> >> >> think),<br>
>> >> >> >> but<br>
>> >> >> >> >> >> > every now and then, these errors (warnings?) show up:<br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 628043: DEBUG: watchdog<br>
>> heartbeat:<br>
>> >> >> send<br>
>> >> >> >> >> >> heartbeat<br>
>> >> >> >> >> >> > signal to db-replica3-priv:9694<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 628043: LOCATION:<br>
>> >> wd_heartbeat.c:771<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 627958: LOG: exit handler called<br>
>> >> >> >> (signal: 2)<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 627958: LOCATION:<br>
>> >> pgpool_main.c:1272<br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> > *2025-06-01 09:11:00: pid 627958: WARNING: failed to lock<br>
>> >> >> >> >> >> > semaphore2025-06-01 09:11:00: pid 627958: DETAIL: Invalid<br>
>> >> >> >> >> >> argument*2025-06-01<br>
>> >> >> >> >> >> > 09:11:00: pid 627958: LOCATION: pool_sema.c:129<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 627958: WARNING: failed to<br>
>> unlock<br>
>> >> >> >> semaphore<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 627958: DETAIL: Invalid argument<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 627958: LOCATION:<br>
>> pool_sema.c:202<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 627958: LOG: shutting down by<br>
>> >> signal 2<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 627958: LOCATION:<br>
>> >> pgpool_main.c:1324<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 627958: LOG: terminating all<br>
>> child<br>
>> >> >> >> processes<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 627958: LOCATION:<br>
>> >> pgpool_main.c:1334<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 628047: WARNING: failed to lock<br>
>> >> >> semaphore<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 628047: DETAIL: Invalid argument<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 628047: LOCATION:<br>
>> pool_sema.c:129<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 628042: WARNING: failed to lock<br>
>> >> >> semaphore<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 628042: DETAIL: Invalid argument<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 628042: LOCATION:<br>
>> pool_sema.c:129<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 628039: WARNING: failed to lock<br>
>> >> >> semaphore<br>
>> >> >> >> >> >> > 2025-06-01 09:11:00: pid 628039: DETAIL: Invalid argument<br>
>> >> >> >> >> >><br>
>> >> >> >> >> >> Can you share the result of "ipcs -s" so that I can confirm<br>
>> >> pgpool<br>
>> >> >> >> >> >> properly allocates the semaphore.<br>
>> >> >> >> >> >><br>
>> >> >> >> >> >> By the way do you see "WARNING: failed to unlock semaphore"<br>
>> >> only<br>
>> >> >> when<br>
>> >> >> >> >> >> pgpool is shutting down?<br>
>> >> >> >> >> >><br>
>> >> >> >> >> >> > Also, earlier in the log, I see errors about being unable<br>
>> to<br>
>> >> >> >> create a<br>
>> >> >> >> >> >> > socket, for some reason it's trying (and failing) to<br>
>> create<br>
>> >> >> socket<br>
>> >> >> >> on<br>
>> >> >> >> >> >> > localhost (<a href="http://127.0.0.1:9694" rel="noreferrer" target="_blank">127.0.0.1:9694</a>) and "creating socket on<br>
>> >> ::1:9694".<br>
>> >> >> >> Are<br>
>> >> >> >> >> >> these<br>
>> >> >> >> >> >> > "ok to ignore"?<br>
>> >> >> >> >> >><br>
>> >> >> >> >> >> First of all "creating socket on ::1:9694" looks unusual<br>
>> >> because<br>
>> >> >> it<br>
>> >> >> >> >> >> means that heartbeat_hostname is set to "::1", which is the<br>
>> >> IPv6<br>
>> >> >> loop<br>
>> >> >> >> >> >> back address. heartbeat_hostname is expected to be set IPv4<br>
>> or<br>
>> >> >> IPv6<br>
>> >> >> >> >> >> inet addesss (not loop back address).<br>
>> >> >> >> >> >><br>
>> >> >> >> >> >> For now, I would like to wait for your reply regarding<br>
>> these my<br>
>> >> >> >> >> >> questions above.<br>
>> >> >> >> >> >><br>
>> >> >> >> >> >> Best regards,<br>
>> >> >> >> >> >> --<br>
>> >> >> >> >> >> Tatsuo Ishii<br>
>> >> >> >> >> >> SRA OSS K.K.<br>
>> >> >> >> >> >> English: <a href="http://www.sraoss.co.jp/index_en/" rel="noreferrer" target="_blank">http://www.sraoss.co.jp/index_en/</a><br>
>> >> >> >> >> >> Japanese:<a href="http://www.sraoss.co.jp" rel="noreferrer" target="_blank">http://www.sraoss.co.jp</a><br>
>> >> >> >> >> >><br>
>> >> >> >> >> >><br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634772: DETAIL: creating socket<br>
>> on<br>
>> >> >> >> >> >> <a href="http://127.0.0.1:9694" rel="noreferrer" target="_blank">127.0.0.1:9694</a><br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634772: LOCATION:<br>
>> >> wd_heartbeat.c:385<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634772: LOG: set SO_REUSEPORT<br>
>> >> option<br>
>> >> >> to<br>
>> >> >> >> the<br>
>> >> >> >> >> >> socket<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634772: LOCATION:<br>
>> >> wd_heartbeat.c:891<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634772: LOG: creating watchdog<br>
>> >> >> heartbeat<br>
>> >> >> >> >> >> receive<br>
>> >> >> >> >> >> > socket.<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634772: DETAIL: creating socket<br>
>> on<br>
>> >> >> >> ::1:9694<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634772: LOCATION:<br>
>> >> wd_heartbeat.c:385<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634772: LOG: failed to create<br>
>> >> watchdog<br>
>> >> >> >> >> >> heartbeat<br>
>> >> >> >> >> >> > receive socket. retrying...<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634772: DETAIL: bind failed with<br>
>> >> >> reason:<br>
>> >> >> >> >> >> "Cannot<br>
>> >> >> >> >> >> > assign requested address"<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634772: LOCATION:<br>
>> >> wd_heartbeat.c:394<br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> > 2025-06-01 09:11:22: pid 635274: DEBUG:<br>
>> >> >> >> verify_backend_node_status:<br>
>> >> >> >> >> >> > true_primary 0<br>
>> >> >> >> >> >> > 2025-06-01 09:11:22: pid 635274: LOCATION:<br>
>> >> pgpool_main.c:2704<br>
>> >> >> >> >> >> > 2025-06-01 09:11:22: pid 635274: DEBUG: node status[0]: 1<br>
>> >> >> >> >> >> > 2025-06-01 09:11:22: pid 635274: LOCATION:<br>
>> >> >> pool_worker_child.c:267<br>
>> >> >> >> >> >> > 2025-06-01 09:11:22: pid 635274: DEBUG: node status[1]: 2<br>
>> >> >> >> >> >> > 2025-06-01 09:11:22: pid 635274: LOCATION:<br>
>> >> >> pool_worker_child.c:267<br>
>> >> >> >> >> >> > 2025-06-01 09:11:22: pid 635274: DEBUG: node status[2]: 2<br>
>> >> >> >> >> >> > 2025-06-01 09:11:22: pid 635274: LOCATION:<br>
>> >> >> pool_worker_child.c:267<br>
>> >> >> >> >> >> > 2025-06-01 09:11:22: pid 635274: DEBUG: node status[3]: 2<br>
>> >> >> >> >> >> > 2025-06-01 09:11:22: pid 635274: LOCATION:<br>
>> >> >> pool_worker_child.c:267<br>
>> >> >> >> >> >> > 2025-06-01 09:11:22: pid 635274: DEBUG:<br>
>> >> >> >> >> pool_release_follow_primary_lock<br>
>> >> >> >> >> >> > called<br>
>> >> >> >> >> >> > 2025-06-01 09:11:22: pid 635274: LOCATION:<br>
>> >> pgpool_main.c:4106<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634765: LOG: set SO_REUSEPORT<br>
>> >> option<br>
>> >> >> to<br>
>> >> >> >> the<br>
>> >> >> >> >> >> socket<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634765: LOCATION:<br>
>> >> wd_heartbeat.c:891<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634765: LOG: creating watchdog<br>
>> >> >> heartbeat<br>
>> >> >> >> >> >> receive<br>
>> >> >> >> >> >> > socket.<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634765: DETAIL: creating socket<br>
>> on<br>
>> >> >> >> >> >> <a href="http://127.0.0.1:9694" rel="noreferrer" target="_blank">127.0.0.1:9694</a><br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634765: LOCATION:<br>
>> >> wd_heartbeat.c:385<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634765: LOG: set SO_REUSEPORT<br>
>> >> option<br>
>> >> >> to<br>
>> >> >> >> the<br>
>> >> >> >> >> >> socket<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634765: LOCATION:<br>
>> >> wd_heartbeat.c:891<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634765: LOG: creating watchdog<br>
>> >> >> heartbeat<br>
>> >> >> >> >> >> receive<br>
>> >> >> >> >> >> > socket.<br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> > *2025-06-01 09:11:23: pid 634765: DETAIL: creating<br>
>> socket on<br>
>> >> >> >> >> >> > ::1:96942025-06-01 09:11:23: pid 634765: LOCATION:<br>
>> >> >> >> >> >> > wd_heartbeat.c:3852025-06-01 09:11:23: pid 634765: LOG:<br>
>> >> >> failed to<br>
>> >> >> >> >> >> create<br>
>> >> >> >> >> >> > watchdog heartbeat receive socket. retrying...*2025-06-01<br>
>> >> >> 09:11:23:<br>
>> >> >> >> >> pid<br>
>> >> >> >> >> >> > 634765: DETAIL: bind failed with reason: "Cannot assign<br>
>> >> >> requested<br>
>> >> >> >> >> >> address"<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634765: LOCATION:<br>
>> >> wd_heartbeat.c:394<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634767: LOG: set SO_REUSEPORT<br>
>> >> option<br>
>> >> >> to<br>
>> >> >> >> the<br>
>> >> >> >> >> >> socket<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634767: LOCATION:<br>
>> >> wd_heartbeat.c:891<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634767: LOG: creating socket for<br>
>> >> >> sending<br>
>> >> >> >> >> >> heartbeat<br>
>> >> >> >> >> >> > 2025-06-01 09:11:23: pid 634767: DETAIL: set SO_REUSEPORT<br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> > Other odd errors I see in the logs later on are when<br>
>> pgpool<br>
>> >> >> tries<br>
>> >> >> >> to<br>
>> >> >> >> >> run<br>
>> >> >> >> >> >> > escalation script - can't quite find where it's failing to<br>
>> >> find<br>
>> >> >> >> ipv4<br>
>> >> >> >> >> >> > address:<br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> > 2025-06-01 00:07:15: pid 395780: LOG: Pgpool-II parent<br>
>> >> process<br>
>> >> >> >> >> received<br>
>> >> >> >> >> >> > SIGUSR1<br>
>> >> >> >> >> >> > 2025-06-01 00:07:15: pid 395780: LOG: Pgpool-II parent<br>
>> >> process<br>
>> >> >> >> >> received<br>
>> >> >> >> >> >> > watchdog quorum change signal from watchdog<br>
>> >> >> >> >> >> > 2025-06-01 00:07:15: pid 396973: LOG: watchdog:<br>
>> escalation<br>
>> >> >> started<br>
>> >> >> >> >> >> > 2025-06-01 00:07:15: pid 395786: LOG: Setting failover<br>
>> >> command<br>
>> >> >> >> >> timeout<br>
>> >> >> >> >> >> to<br>
>> >> >> >> >> >> > 135<br>
>> >> >> >> >> >> > 2025-06-01 00:07:15: pid 395780: LOG: watchdog cluster<br>
>> now<br>
>> >> >> holds<br>
>> >> >> >> the<br>
>> >> >> >> >> >> quorum<br>
>> >> >> >> >> >> > 2025-06-01 00:07:15: pid 395780: DETAIL: updating the<br>
>> state<br>
>> >> of<br>
>> >> >> >> >> >> quarantine<br>
>> >> >> >> >> >> > backend nodes<br>
>> >> >> >> >> >> > Sun Jun 1 12:07:15 AM CEST 2025<br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> > *escalation.sh: - remove VIP IP from all nodesNode:<br>
>> >> >> >> >> db-primary-privError:<br>
>> >> >> >> >> >> > ipv4: Address not found.Node: db-replica1-privError: ipv4:<br>
>> >> >> Address<br>
>> >> >> >> not<br>
>> >> >> >> >> >> > found.Node: db-replica2-privError: ipv4: Address not<br>
>> >> found.Node:<br>
>> >> >> >> >> >> > db-replica3-privError: ipv4: Address not found.*2025-06-01<br>
>> >> >> >> 00:07:20:<br>
>> >> >> >> >> pid<br>
>> >> >> >> >> >> > 396973: LOG: watchdog escalation successful<br>
>> >> >> >> >> >> > 2025-06-01 00:07:23: pid 396973: LOG: successfully<br>
>> acquired<br>
>> >> the<br>
>> >> >> >> >> delegate<br>
>> >> >> >> >> >> > IP:"192.168.77.130"<br>
>> >> >> >> >> >> > 2025-06-01 00:07:23: pid 396973: DETAIL: 'if_up_cmd'<br>
>> >> returned<br>
>> >> >> with<br>
>> >> >> >> >> >> success<br>
>> >> >> >> >> >> > 2025-06-01 00:07:23: pid 395786: LOG: watchdog escalation<br>
>> >> >> process<br>
>> >> >> >> >> with<br>
>> >> >> >> >> >> > pid: 396973 exit with SUCCESS.<br>
>> >> >> >> >> >> > 2025-06-01 00:07:27: pid 395962: WARNING: failed to lock<br>
>> >> >> semaphore<br>
>> >> >> >> >> >> > 2025-06-01 00:07:27: pid 395962: DETAIL: Invalid argument<br>
>> >> >> >> >> >> > 2025-06-01 00:07:27: pid 395962: WARNING: failed to<br>
>> unlock<br>
>> >> >> >> semaphore<br>
>> >> >> >> >> >> > 2025-06-01 00:07:27: pid 395962: DETAIL: Invalid argument<br>
>> >> >> >> >> >> > 2025-06-01 00:07:28: pid 396924: WARNING: failed to lock<br>
>> >> >> semaphore<br>
>> >> >> >> >> >> > 2025-06-01 00:07:28: pid 396924: DETAIL: Invalid argument<br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> > The way I started was I copied pgpool.conf from the "old"<br>
>> and<br>
>> >> >> >> working<br>
>> >> >> >> >> >> > pgpool 4.2 configuration and modified it slightly, though<br>
>> >> >> nothing<br>
>> >> >> >> >> >> > major,changed hostnames and i.e. delegate_ip variable name<br>
>> >> was<br>
>> >> >> >> changed<br>
>> >> >> >> >> >> > from delegate_IP. Also added this variable as without<br>
>> it, I<br>
>> >> >> didn't<br>
>> >> >> >> >> see a<br>
>> >> >> >> >> >> > socket created for port 9898:<br>
>> >> >> >> >> >> > unix_socket_directories = '/var/run/postgresql'<br>
>> >> >> >> >> >> > I had to change network interfaces as well, in the RHEL it<br>
>> >> was<br>
>> >> >> >> using<br>
>> >> >> >> >> eth0<br>
>> >> >> >> >> >> > where on Ubuntu it's ens18, so I changed lines like:<br>
>> >> >> >> >> >> > /usr/bin/sudo /sbin/ip addr add $_IP_$/23 dev ens18 label<br>
>> >> >> ens18:0<br>
>> >> >> >> >> >> > Other thing I had to change was path to arping as on<br>
>> Ubuntu<br>
>> >> 24<br>
>> >> >> >> it's in<br>
>> >> >> >> >> >> > /usr/bin (not sbin)<br>
>> >> >> >> >> >> > arping_cmd = '/usr/bin/sudo /usr/bin/arping -U $_IP_$ -w<br>
>> 1<br>
>> >> -I<br>
>> >> >> >> ens18'<br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> > The other thing I'm confused about, I have two network<br>
>> >> >> interfaces<br>
>> >> >> >> on<br>
>> >> >> >> >> each<br>
>> >> >> >> >> >> > host, i.e.<br>
>> >> >> >> >> >> > <a href="http://192.168.77.135/23" rel="noreferrer" target="_blank">192.168.77.135/23</a> brd 192.168.77.255 scope global ens18<br>
>> >> >> >> >> >> > and<br>
>> >> >> >> >> >> > inet <a href="http://192.168.78.135/24" rel="noreferrer" target="_blank">192.168.78.135/24</a> brd 192.168.78.255 scope global<br>
>> ens19<br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> > In pgpool.conf, it is referencing the "priv" hosts (i.e.<br>
>> >> >> >> >> >> > heartbeat_hostname2 = 'db-replica2-priv'), which<br>
>> >> theoretically<br>
>> >> >> >> should<br>
>> >> >> >> >> be<br>
>> >> >> >> >> >> on<br>
>> >> >> >> >> >> > ens19 network interface as shown above, but in my old<br>
>> >> >> pgpool.conf,<br>
>> >> >> >> it<br>
>> >> >> >> >> was<br>
>> >> >> >> >> >> > only referencing eth0 on RHEL, even though "priv" hosts<br>
>> were<br>
>> >> on<br>
>> >> >> >> eth1.<br>
>> >> >> >> >> >> I'm<br>
>> >> >> >> >> >> > wondering if that needs to be changed in Ubuntu or it<br>
>> makes<br>
>> >> no<br>
>> >> >> >> >> difference<br>
>> >> >> >> >> >> > here?<br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> > Right now, I can't quite figure out whether it is<br>
>> something<br>
>> >> >> with<br>
>> >> >> >> >> >> > pgpool.conf or with the Ubuntu settings and the semaphore<br>
>> >> error<br>
>> >> >> is<br>
>> >> >> >> >> quite<br>
>> >> >> >> >> >> > cryptic. If you need me to post some parts of my<br>
>> >> pgpool.conf,<br>
>> >> >> >> please<br>
>> >> >> >> >> >> > advise which. I've seen an older version of the FAQ that<br>
>> >> said<br>
>> >> >> >> repmgr<br>
>> >> >> >> >> and<br>
>> >> >> >> >> >> > pgpool don't work together but then I saw mention that<br>
>> this<br>
>> >> was<br>
>> >> >> no<br>
>> >> >> >> >> longer<br>
>> >> >> >> >> >> > the case.<br>
>> >> >> >> >> >> ><br>
>> >> >> >> >> >> > I would much appreciate any help you can provide in<br>
>> solving<br>
>> >> this<br>
>> >> >> >> >> problem.<br>
>> >> >> >> >> >><br>
>> >> >> >> >><br>
>> >> >> >><br>
>> >> >><br>
>> >><br>
>><br>
_______________________________________________<br>
pgpool-general mailing list<br>
<a href="mailto:pgpool-general@pgpool.net" target="_blank">pgpool-general@pgpool.net</a><br>
<a href="http://www.pgpool.net/mailman/listinfo/pgpool-general" rel="noreferrer" target="_blank">http://www.pgpool.net/mailman/listinfo/pgpool-general</a><br>
</blockquote></div>