How can I write to a file on disk from PL/pgSQL?

Question

I would like to do the equivalent of c or php fopen() and fwrite(). I am not trying to dump a table to disk. I am trying to do some debug logging during development.

Answer 1

You can use plpythonu f.open(), f.write(), f.close() within a postgres function to write to a file.

Language extension would need to be installed.,

https://www.postgresql.org/docs/8.3/static/plpython.html

Working example from the mailing list. https://www.postgresql.org/message-id/flat/20041106125209.55697.qmail%40web51806.mail.yahoo.com#20041106125209.55697.qmail@web51806.mail.yahoo.com

for example plpythonu

CREATE FUNCTION makefile(text) RETURNS text AS '\n
o=open("/path/to/file")
o.write(args[0])
o.close()
return "ok"
' LANGUAgE plpythonu;

Regards Tino