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PostgreSQL database adapter for the Python programming language
ac14957fbb
There's a race condition that only seems to happen over Unix-domain sockets. Sometimes, the closed socket is reported by the kernel to libpq like this (captured with strace): sendto(3, "Q\0\0\0\34select pg_backend_pid()\0", 29, MSG_NOSIGNAL, NULL, 0) = 29 recvfrom(3, "E\0\0\0mSFATAL\0C57P01\0Mterminating "..., 16384, 0, NULL, NULL) = 110 recvfrom(3, 0x12d0330, 16384, 0, 0, 0) = -1 ECONNRESET (Connection reset by peer) That is, psycopg2/libpq sees no error when sending the first query after the connection is closed, but gets an error reading the result. In that case, everything worked fine. But sometimes, the error manifests like this: sendto(3, "Q\0\0\0\34select pg_backend_pid()\0", 29, MSG_NOSIGNAL, NULL, 0) = -1 EPIPE (Broken pipe) recvfrom(3, "E\0\0\0mSFATAL\0C57P01\0Mterminating "..., 16384, 0, NULL, NULL) = 110 recvfrom(3, "", 16274, 0, NULL, NULL) = 0 recvfrom(3, "", 16274, 0, NULL, NULL) = 0 i.e. libpq received an error when sending the query. This manifests as a slightly different exception from a slightly different place. More importantly, in this case connection.closed is left at 0 rather than being set to 2, and that is the bug I'm fixing here. Note that we see almost identical behaviour for sync and async connections, and the fixes are the same. So I added extremely similar test cases. Finally, there is still a bug here: for async connections, we sometimes raise DatabaseError (incorrect) and sometimes raise OperationalError (correct). Will fix that next. |
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| doc | ||
| examples | ||
| lib | ||
| psycopg | ||
| sandbox | ||
| scripts | ||
| tests | ||
| .gitignore | ||
| .travis.yml | ||
| AUTHORS | ||
| INSTALL | ||
| LICENSE | ||
| Makefile | ||
| MANIFEST.in | ||
| NEWS | ||
| psycopg2.cproj | ||
| psycopg2.sln | ||
| README.rst | ||
| setup.cfg | ||
| setup.py | ||
| tox.ini | ||
psycopg2 - Python-PostgreSQL Database Adapter
=============================================
Psycopg is the most popular PostgreSQL database adapter for the Python
programming language. Its main features are the complete implementation of
the Python DB API 2.0 specification and the thread safety (several threads can
share the same connection). It was designed for heavily multi-threaded
applications that create and destroy lots of cursors and make a large number
of concurrent "INSERT"s or "UPDATE"s.
Psycopg 2 is mostly implemented in C as a libpq wrapper, resulting in being
both efficient and secure. It features client-side and server-side cursors,
asynchronous communication and notifications, "COPY TO/COPY FROM" support.
Many Python types are supported out-of-the-box and adapted to matching
PostgreSQL data types; adaptation can be extended and customized thanks to a
flexible objects adaptation system.
Psycopg 2 is both Unicode and Python 3 friendly.
Documentation
-------------
Documentation is included in the 'doc' directory and is `available online`__.
.. __: http://initd.org/psycopg/docs/
Installation
------------
If all the dependencies are met (i.e. you have the Python and libpq
development packages installed in your system) the standard::
python setup.py build
sudo python setup.py install
should work no problem. In case you have any problem check the 'install' and
the 'faq' documents in the docs or online__.
.. __: http://initd.org/psycopg/docs/install.html
For any other resource (source code repository, bug tracker, mailing list)
please check the `project homepage`__.
.. __: http://initd.org/psycopg/