Psycopg2 about undefined symbol:lo_truncate64 solutions

Today, when installing PSYCOPG2 under centos6.5 and using Python to connect to the PostgreSQL database, there was a undefined symbol:lo_truncate6 error:

Django.core.exceptions.ImproperlyConfigured:Error loading PSYCOPG2 module:/mydev/pyweb/cancerdb/lib/python2.7/ site-packages/psycopg2/_psycopg.so:undefined symbol:lo_truncate64

The reason, as Http://initd.org/psycopg/docs/faq.html describes:

"This means that PSYCOPG is compiled with lo_truncate () support (i.e. the LIBPQ used at compile time WA S version >= 8.3) but at runtime a older LIBPQ dynamic library is found. Fast-forward several years, if the message reports undefined symbol:lo_truncate64 It means that PSYCOPG was Buil T with large objects-bits API support (i.e. the LIBPQ used at compile time is at least 9.3) but at runtime an Older LIBPQ Dynamic library is found. "

(PSYCOPG uses lo_truncate () to compile at least 9.3 or more versions, but at compile time it discovers a lower version of LIBPQ. ）

On the internet to see a lot of people by modifying the PSYCOPG2 installation package under the setup.cfg , add PostgreSQL pg_config, and then re-install PSYCOPG2 manually to solve:

£ º£vi  setup.cfg ... # full path.pg_config=/usr/local/psql- 9.4. 0/bin/1fordate/ time representation.use_ Pydatetime=1 .....

Try to find that this method can not solve the problem fundamentally, undefined symbol:lo_truncate6 error still exists.

After some groping, combined with the official documents of PSYCOPG2 , later discovered the need to replace the libpq.so.5 of PostgreSQL with the libpq.so.5 of the system, Re-install the PSYCOPG2, the problem can be resolved:

1. Find what's the LIBPQ dynamic library used at runtime (find LIBPQ dynamics libraries used during the run):

grep LIBPQ   

2. Can avoid the problem by using the same version of the pg_config at install time and the LIBPQ at runtime (for LIBPQ Dynamic Library in the run process):

[Email protected] -: -: $/usr/local/download/psycopg2-2.6.1= cd/usr/Lib64[email protected] -: -: the/usr/lib64=RMLibpq.so.5[email protected] -: -: the/usr/lib64=LN-s/usr/local/postgresql-9.4.0/lib/libpq.so.5./

3, reinstall PSYCOPG2, solve the problem.

[Email protected] -: -: the/mydev/pyweb/download/psycopg2-2.5.4=Pythonpython2.7.5(Default, Jan -  -, -: +: -) [GCC4.4.7 20120313(Red Hat4.4.7- One)] on Linux2type" Help","Copyright","credits"Or"License"  for  Moreinformation.>>>Import PSYCOPG2>>>

Psycopg2 about undefined symbol:lo_truncate64 solutions