This post got me thinking, is there a similar procedure for PL/pgSQL functions? --- David Gardner, IT The Yucaipa Companies (310) 228-2855 -----Original Message----- From: pgsql-general-owner@xxxxxxxxxxxxxx [mailto:pgsql-general-owner@xxxxxxxxxxxxxx] On Behalf Of Joe Conway Sent: Friday, June 01, 2007 9:00 PM To: Islam Hegazy Cc: pgsql-general@xxxxxxxxxxxxxx Subject: Re: [GENERAL] debugging C functions Islam Hegazy wrote: > I wrote a C function to call from PostgreSQL8.2.4 under Linux. The > functions returns unexpected results. I did an extensive analysis to the > function and it seems correct. I want to know if there is a way to debug > C functions that are passed to PostgreSQL. Yes. Something along these lines (where plr.so is an example shared object library with a function called throw_notice installed in a database called contrib_regression): 1. Build and install your function. Ensure both postgres and your library are built with debug symbols (--enable-debug) 2. start a psql session in the database where your function has been created #psql contrib_regression 3. Load the shared object library in psql contrib_regression=# load '$libdir/plr'; LOAD 4. Start another console and determine the PID for the backend session (this will wrap poorly -- I'll do my best to make it readable) ps -ef | grep postgres postgres 24496 1 0 18:23 ? 00:00:00 /usr/local/pgsql-dev/bin/postgres -D /opt/data/pgsql/data -p 65432 -i -F postgres 24498 24496 0 18:23 ? 00:00:00 postgres: writer process postgres 24499 24496 0 18:23 ? 00:00:00 postgres: stats collector process postgres 24500 24496 0 18:23 ? 00:00:00 postgres: autovacuum launcher process postgres 31233 24496 1 20:37 ? 00:00:00 postgres: postgres contrib_regression [local] idle You want the PID associated with the idle session -- 31233 5. Run gdb and attach to the backend in question gdb /usr/local/pgsql-dev/bin/postgres 31233 6. Set breakpoints, etc, and then continue the gdb session [...] Reading symbols from /usr/lib64/R/library/stats/libs/stats.so...done. Loaded symbols for /usr/lib64/R/library/stats/libs/stats.so 0x0000003fef4cdf45 in recv () from /lib64/libc.so.6 (gdb) break throw_notice Breakpoint 1 at 0x636cb7: file plr.c, line 2908. (gdb) continue Continuing. 7. Return to the psql session, run your function contrib_regression=# select throw_notice('hello'); 8. Return to gdb session, debug away... HTH, Joe ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
