Segmentation fault when running COPY statement

[jkldv]

When I try to execute a COPY to a oracle_fdw foreign table, the thread crashes with segmentation fault. When I use postgres_fdw foreign table, this operation works fine and results in INSERT statements to the remote postgres database table.

[oracle_fdw]$ cat tmp | psql testdb_remote postgres -c 'copy garbage from stdin'
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.

Postgres log isn't terribly enlightening (and yes, my table is literally named 'garbage'):
2019-04-16 12:00:17.523 CDT [30505] LOG: server process (PID 26078) was terminated by signal 11: Segmentation fault
2019-04-16 12:00:17.523 CDT [30505] DETAIL: Failed process was running: copy garbage from stdin
2019-04-16 12:00:17.523 CDT [30505] LOG: terminating any other active server processes
2019-04-16 12:00:17.524 CDT [22378] WARNING: terminating connection because of crash of another server process

I'm pretty sure COPY should be allowed from experience with another FDW:
[postgres_fdw]$ cat tmp | psql testdb postgres -c 'copy rel_11.garbage from stdin'
COPY 1

[jkldv]

Here's some more info I was able to grab.
/var/log/messages:
postmaster[26078]: segfault at 58 ip 00007fe7550984a8 sp 00007ffcc38d5af0 error 6 in oracle_fdw.so[7fe75508c000+21000]

core_backtrace:
[ { "address": 139774236566696
, "build_id": "b136ddb4c640a21dd8ec1432808b93e5b47bbfcf"
, "build_id_offset": 50344
, "function_name": "oracleExecForeignInsert"
, "file_name": "/usr/pgsql-11/lib/oracle_fdw.so"
}
, { "address": 5859560
, "build_id": "276dd96b90b1b030fe6113685407134a8f7148c3"
, "build_id_offset": 1665256
, "function_name": "CopyFrom"
, "file_name": "/usr/pgsql-11/bin/postgres"
}
, { "address": 5861445
, "build_id": "276dd96b90b1b030fe6113685407134a8f7148c3"
, "build_id_offset": 1667141
, "function_name": "DoCopy"
, "file_name": "/usr/pgsql-11/bin/postgres"
}

[jkldv]

With debug3, I see this log
2019-04-16 15:25:06.049 CDT [30259] DEBUG: oracle_fdw: execute foreign table insert on 34084
2019-04-16 15:25:06.049 CDT [30259] CONTEXT: COPY garbage, line 1: "7 steel 88"
2019-04-16 15:25:06.285 CDT [30201] DEBUG: server process (PID 30259) was terminated by signal 11: Segmentation fault

[jkldv]

Old school debugging with logs shows:
WARNING: oracle_fdw: fdw_state: 0

[jkldv]

My suspicion is that this is caused by lack of implementation of BeginForeignInsert and EndForeignInsert. This is judging by the debug logs (almost none print for COPY vs INSERT)

[laurenz]

Yes, absolutely.
This function is not called for COPY.

I'll see if I can add support, otherwise I'll just forbid COPY.
Crashing is not an option.

[laurenz]

This was more work than I expected.
Could you test if it works for you now?

[jkldv]

Worked perfectly! Thank you very much for your help.

Before:

$ cat tmp | psql testdb_remote postgres -c "copy garbage from stdin"
WARNING:  oracle_fdw: execute foreign table insert on 34084
WARNING:  oracle_fdw: fdw_state: 0
server closed the connection unexpectedly
	This probably means the server terminated abnormally
	before or while processing the request.

After:

$ cat tmp | psql testdb_remote postgres -c "copy garbage from stdin"
COPY 11