How to Debug PostgreSQL

First, compile the source code use ./configure --prefix=XXXX --enable-debug && CFLAGS=-O0

then make and make install.

IF you want to RESTART PG

Detected if there is an instance of Postgre server. If there is, kill it. use

ps -e | grep postgre
// find id of the process
kill -9 $processid

to detect the pocess of postgresql and kill it.

then use:

gdb postgresqlHomeDIR/bin/postgres -quiet
// enter gdb then use
set args -D DATADIR
run

here DATADIR and postgresqlDIR are your own directory.

IF you don't want to RESTART PG

// find postgres pid
pid = `ps auxww | \
    grep postgres: | \
    grep -v -e 'grep postgres:' -e 'postgres: stats' -e 'postgres: writer' -e 'postgres: archiver' -e 'postgres: logger' -e 'postgres: autovacuum' | \
    tee /dev/tty | \
    awk '{print $2}'`
gdb pid

then use

./psql test

to test. Here test is  your database name.

IF you want to debug contrib

make && make install in contrib/yourdir

then go to gdb to file your shard lib to load symbol. Here XXX.so is your contrib share lib.

(gdb) file XXX.so

if not, when you use break somefunction, it will report:

No symbol table is loaded.  Use the “file” command.
Make breakpoint pending on future shared library load? (y or [n])