gdb를 통한 postgresql 소스 디버깅

1. gdb 를 설치합니다.

yum install gdb

2. postgresql 설치 전 configure 옵션으로 옵티마이져 모드를 비활성화 하는것이 좋습니다.

./configure --enable-cassert --enable-debug CFLAGS="-ggdb -O0"

3. 소스를 이용하여 컴파일 설치가 완료되고 나면 

backend process pid를 확인하여 gdb attach 구문으로 디버깅을 수행할 수 있습니다. 

# 디버깅하려하는 프로세스 아이디 확인

test=# select pg_backend_pid();
 pg_backend_pid 
----------------
           3167
(1 row)

# pid를 attach 하여 디버깅 실행

$ gdb -p 3167

GNU gdb (GDB) Red Hat Enterprise Linux (7.2-60.el6_4.1)

Copyright (C) 2010 Free Software Foundation, Inc.

License GPLv3+: GNU GPL version 3 or later 


This is free software: you are free to change and redistribute it.

There is NO WARRANTY, to the extent permitted by law.  Type "show copying"

and "show warranty" for details.

This GDB was configured as "x86_64-redhat-linux-gnu".

For bug reporting instructions, please see:

.

Attaching to process 3193

Reading symbols from /usr/local/pgsql93/bin/postgres...done.

Reading symbols from /usr/lib64/libssl.so.10...(no debugging symbols found)...done.

Loaded symbols for /usr/lib64/libssl.so.10

Reading symbols from /usr/lib64/libcrypto.so.10...(no debugging symbols found)...done.

Loaded symbols for /usr/lib64/libcrypto.so.10

Reading symbols from /lib64/libdl.so.2...(no debugging symbols found)...done.

Loaded symbols for /lib64/libdl.so.2

Reading symbols from /lib64/libm.so.6...(no debugging symbols found)...done.

Loaded symbols for /lib64/libm.so.6

Reading symbols from /lib64/libc.so.6...(no debugging symbols found)...done.

Loaded symbols for /lib64/libc.so.6

Reading symbols from /lib64/libgssapi_krb5.so.2...(no debugging symbols found)...done.

Loaded symbols for /lib64/libgssapi_krb5.so.2

Reading symbols from /lib64/libkrb5.so.3...(no debugging symbols found)...done.

Loaded symbols for /lib64/libkrb5.so.3

Reading symbols from /lib64/libcom_err.so.2...(no debugging symbols found)...done.

Loaded symbols for /lib64/libcom_err.so.2

Reading symbols from /lib64/libk5crypto.so.3...(no debugging symbols found)...done.

Loaded symbols for /lib64/libk5crypto.so.3

Reading symbols from /lib64/libz.so.1...(no debugging symbols found)...done.

Loaded symbols for /lib64/libz.so.1

Reading symbols from /lib64/ld-linux-x86-64.so.2...(no debugging symbols found)...done.

Loaded symbols for /lib64/ld-linux-x86-64.so.2

Reading symbols from /lib64/libkrb5support.so.0...(no debugging symbols found)...done.

Loaded symbols for /lib64/libkrb5support.so.0

Reading symbols from /lib64/libkeyutils.so.1...(no debugging symbols found)...done.

Loaded symbols for /lib64/libkeyutils.so.1

Reading symbols from /lib64/libresolv.so.2...(no debugging symbols found)...done.

Loaded symbols for /lib64/libresolv.so.2

Reading symbols from /lib64/libpthread.so.0...(no debugging symbols found)...done.

[Thread debugging using libthread_db enabled]

Loaded symbols for /lib64/libpthread.so.0

Reading symbols from /lib64/libselinux.so.1...(no debugging symbols found)...done.

Loaded symbols for /lib64/libselinux.so.1

Reading symbols from /lib64/libnss_files.so.2...(no debugging symbols found)...done.

Loaded symbols for /lib64/libnss_files.so.2

0x0000003f002e98c2 in recv () from /lib64/libc.so.6

Missing separate debuginfos, use: debuginfo-install glibc-2.12-1.132.el6_5.2.x86_64 keyutils-libs-1.4-4.el6.x86_64 krb5-libs-1.10.3-15.el6_5.1.x86_64 libcom_err-1.41.12-18.el6.x86_64 libselinux-2.0.94-5.3.el6_4.1.x86_64 openssl-1.0.1e-16.el6_5.14.x86_64 zlib-1.2.3-29.el6.x86_64

(gdb)

# breakpoint 지정

(gdb) b raw_parser
Breakpoint 1 at 0x57a733: file parser.c, line 42.
(gdb) 

# 쿼리실행

test=# select 'this is test'; // gdb 컨트롤 대기

# 디버깅 컨트롤

 (gdb) continue

Continuing.

 

Breakpoint 1, raw_parser (str=0x253dd38 "select 'this is test';") at parser.c:42

42              yyscanner = scanner_init(str, &yyextra.core_yy_extra,

(gdb)