Re: How to deal with dangling files after aborted `pg_restore`?

It could be that he only restored *some* tables in an existing database.

On Wed, Dec 18, 2024 at 7:02 PM Saul Perdomo <saul(dot)perdomo(at)gmail(dot)com> wrote:

> Genuine question: Why are you looking to recover from this half-cooked
> state instead of restarting the restore process from the beginning?
>
> On Tue, Dec 17, 2024, 1:10 a.m. Ivan Kurnosov <zerkms(at)zerkms(dot)com> wrote:
>
>> The scenario:
>>
>> 1. There is a postgresql 17 server running
>> 2. Restore dump with `--single-transaction` flag
>> 3. For whatever reason the server goes away (eg: we kill the process)
>> 4. Now `base` directory is filled with abandoned table files which
>> postgresql know nothing about
>>
>> Playground:
>>
>> Terminal 1:
>> Start server: `docker run --rm -it -e POSTGRES_HOST_AUTH_METHOD=trust -v
>> $PWD/postgres:/var/lib/postgresql/data postgres:17.2`
>>
>> Terminal 2:
>> 1. Start container with recent pg_restore: `docker run --rm -it -v
>> $PWD:/app -w /app postgres:17.2 bash`
>> 2. Start dump recovery: `pg_restore -h 172.17.0.2 -U postgres -d postgres
>> --single-transaction -v -Fc --no-owner dump.sql`
>>
>> Terminal 3:
>> 1. Find what container is the server: `docker ps`
>> 2. Kill it: `docker kill d7ecf6e66c1d`
>>
>> Terminal 1:
>> Start the server again, with the same command
>>
>> Terminal 3:
>> Check there are abandoned large files:
>> ```
>> # ls -la /home/ivan/postgres/base/5
>> <truncated>
>> -rw------- 1 systemd-coredump systemd-coredump 342884352 Dec 17 18:58
>> 16399
>> -rw------- 1 systemd-coredump systemd-coredump 11149312 Dec 17 18:58
>> 16404
>> -rw------- 1 systemd-coredump systemd-coredump 188416 Dec 17 18:58
>> 16403_fsm
>> -rw------- 1 systemd-coredump systemd-coredump 686145536 Dec 17 18:58
>> 16403
>> ```
>>
>> Terminal 2:
>> 1. Confirm those OIDs are not accounted:
>> ```
>> psql -h 172.17.0.2 -U postgres -c 'select * from pg_class'|grep 16404
>> psql -h 172.17.0.2 -U postgres -c 'select * from pg_class'|grep 16403
>> psql -h 172.17.0.2 -U postgres -c 'select * from pg_class'|grep 16399
>> ```
>>
>> Hence a question: am I doing something wrong? Is it expected behaviour?
>> If so - how would one recover from this scenario now WITHOUT dropping
>> entire database?
>>
>> --
>> With best regards, Ivan Kurnosov
>>
>

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