Based on development environment of PostgreSQL (./configure && make && make install), install standard glibc debug packages and set PostgreSQL debug mode on, which will be helpful for debugging PostgreSQL.
no debugging symbols found
When attaching with a PostgreSQL backend using gdb in CentOS, maybe find the following information due to lack of corresponding debug packages.
Attaching to process 7427
Reading symbols from /usr/local/pgsql/bin/postgres...(no debugging symbols found)...done.
Reading symbols from /usr/local/pgsql/lib/libpq.so.5...(no debugging symbols found)...done.
Loaded symbols for /usr/local/pgsql/lib/libpq.so.5
Reading symbols from /lib64/libpthread.so.0...(no debugging symbols found)...done.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
Loaded symbols for /lib64/libpthread.so.0
Reading symbols from /lib64/librt.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib64/librt.so.1
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/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/libnss_files.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib64/libnss_files.so.2
Missing separate debuginfos, use: debuginfo-install glibc-2.17-260.el7_6.3.x86_64
Setup standard glibc debug library
Just type tow commands simply to install them.
yum install yum-utils -y
debuginfo-install glibc -y
Then will get the symbols from corresponding debug packages.
Attaching to process 7427
Reading symbols from /usr/local/pgsql/bin/postgres...(no debugging symbols found)...done.
Reading symbols from /usr/local/pgsql/lib/libpq.so.5...(no debugging symbols found)...done.
Loaded symbols for /usr/local/pgsql/lib/libpq.so.5
Reading symbols from /lib64/libpthread.so.0...Reading symbols from /usr/lib/debug/usr/lib64/libpthread-2.17.so.debug...done.
done.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
Loaded symbols for /lib64/libpthread.so.0
Reading symbols from /lib64/librt.so.1...Reading symbols from /usr/lib/debug/usr/lib64/librt-2.17.so.debug...done.
done.
Loaded symbols for /lib64/librt.so.1
Reading symbols from /lib64/libdl.so.2...Reading symbols from /usr/lib/debug/usr/lib64/libdl-2.17.so.debug...done.
done.
Loaded symbols for /lib64/libdl.so.2
Reading symbols from /lib64/libm.so.6...Reading symbols from /usr/lib/debug/usr/lib64/libm-2.17.so.debug...done.
done.
Loaded symbols for /lib64/libm.so.6
Reading symbols from /lib64/libc.so.6...Reading symbols from /usr/lib/debug/usr/lib64/libc-2.17.so.debug...done.
done.
Loaded symbols for /lib64/libc.so.6
Reading symbols from /lib64/ld-linux-x86-64.so.2...Reading symbols from /usr/lib/debug/usr/lib64/ld-2.17.so.debug...done.
done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
Reading symbols from /lib64/libnss_files.so.2...Reading symbols from /usr/lib/debug/usr/lib64/libnss_files-2.17.so.debug...done.
done.
Loaded symbols for /lib64/libnss_files.so.2
Setup PostgreSQL debug library
There’re two lines “no debugging symbols found” information of PostgreSQL in the above output. Now let’s setup the debug libraries for PostgreSQL; two methods will make it.
Add –enable-debug when configure
./configure --enable-debug
make
make install
Modify Makefile.global file manually
# diff src/Makefile.global Makefile.global
249c249
< CFLAGS = -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard -O2
---
> CFLAGS = -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard -g
Then, make && make install
Finally, we will read all symbols to step into debugging.
Attaching to process 2912
Reading symbols from /usr/local/pgsql/bin/postgres...done.
Reading symbols from /usr/local/pgsql/lib/libpq.so.5...done.
Loaded symbols for /usr/local/pgsql/lib/libpq.so.5
Reading symbols from /lib64/libpthread.so.0...Reading symbols from /usr/lib/debug/usr/lib64/libpthread-2.17.so.debug...done.
done.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
Loaded symbols for /lib64/libpthread.so.0
Reading symbols from /lib64/librt.so.1...Reading symbols from /usr/lib/debug/usr/lib64/librt-2.17.so.debug...done.
done.
Loaded symbols for /lib64/librt.so.1
Reading symbols from /lib64/libdl.so.2...Reading symbols from /usr/lib/debug/usr/lib64/libdl-2.17.so.debug...done.
done.
Loaded symbols for /lib64/libdl.so.2
Reading symbols from /lib64/libm.so.6...Reading symbols from /usr/lib/debug/usr/lib64/libm-2.17.so.debug...done.
done.
Loaded symbols for /lib64/libm.so.6
Reading symbols from /lib64/libc.so.6...Reading symbols from /usr/lib/debug/usr/lib64/libc-2.17.so.debug...done.
done.
Loaded symbols for /lib64/libc.so.6
Reading symbols from /lib64/ld-linux-x86-64.so.2...Reading symbols from /usr/lib/debug/usr/lib64/ld-2.17.so.debug...done.
done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
Reading symbols from /lib64/libnss_files.so.2...Reading symbols from /usr/lib/debug/usr/lib64/libnss_files-2.17.so.debug...done.
done.
Loaded symbols for /lib64/libnss_files.so.2
0x00007fbcc1531463 in __epoll_wait_nocancel () at ../sysdeps/unix/syscall-template.S:81
81 T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
分类：Default, PostgreSQL
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