Output from the OTLP service displayed in the log file

[ivucica]

Example:

2025-08-31 13:34:57 UTC [4109375-1753] LOG:  checkpoint starting: time
":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess":{}}{"partialSuccess"2025-08-31 13:35:30 UTC [4109375-1754] LOG:  checkpoint complete: wrote 324 buffers (2.0%); 0 WAL file(s) added, 0 removed, 1 recycled; write=32.299 s, sync=0.011 s, total=32.365 s; sync files=138, longest=0.003 s, average=0.001 s; distance=7068 kB, estimate=11213 kB
2025-08-31 13:39:57 UTC [4109375-1755] LOG:  checkpoint starting: time
2025-08-31 13:40:53 UTC [4109375-1756] LOG:  checkpoint complete: wrote 562 buffers (3.4%); 0 WAL file(s) added, 0 removed, 0 recycled; write=56.536 s, sync=0.016 s, total=56.572 s; sync files=159, longest=0.004 s, average=0.001 s; distance=8786 kB, estimate=10971 kB

The JSON seems like it might be HTTP response body from the otel collector. My guess is that it's coming out of pg_tracing_otel.c's send_json_trace(); specifically, if I understand correctly, libcurl is outputting to stderr by default.

It looks like https://github.com/ivucica/pg_tracing/tree/sinkhole-libcurl resolved the issue (ccbad8b). If it does not look to hacky, I can create a pull request.

Let me know if this makes sense.