Move pyscopg-binary install docs to "quick start" section

This is the fastest way for most folks to get up-and-running
with psycopg. We've seen a lot of noise in the GH issues with people
failng to install the non-binary version. Hopefully this will
make life easier for people new to psycopg/python.

See https://github.com/psycopg/psycopg2/issues/1085#issuecomment-659028139
This commit is contained in:
Edan Schwartz 2020-08-07 14:53:57 -05:00
parent cecff195fc
commit ed3d44562d

View File

@ -8,27 +8,116 @@ Installation
Psycopg is a PostgreSQL_ adapter for the Python_ programming language. It is a Psycopg is a PostgreSQL_ adapter for the Python_ programming language. It is a
wrapper for the libpq_, the official PostgreSQL client library. wrapper for the libpq_, the official PostgreSQL client library.
The `psycopg2` package is the current mature implementation of the adapter: it
is a C extension and as such it is only compatible with CPython_. If you want
to use Psycopg on a different Python implementation (PyPy, Jython, IronPython)
there is a couple of alternative:
- a `Ctypes port`__, but it is not as mature as the C implementation yet
and it is not as feature-complete;
- a `CFFI port`__ which is currently more used and reported more efficient on
PyPy, but please be careful of its version numbers because they are not
aligned to the official psycopg2 ones and some features may differ.
.. _PostgreSQL: https://www.postgresql.org/ .. _PostgreSQL: https://www.postgresql.org/
.. _Python: https://www.python.org/ .. _Python: https://www.python.org/
.. _libpq: https://www.postgresql.org/docs/current/static/libpq.html
.. _CPython: https://en.wikipedia.org/wiki/CPython
.. _Ctypes: https://docs.python.org/library/ctypes.html
.. __: https://github.com/mvantellingen/psycopg2-ctypes
.. __: https://github.com/chtd/psycopg2cffi
.. index::
single: Install; from PyPI
single: Install; wheel
single: Wheel
.. _binary-packages:
Quick Install
-------------
For most operating systems, the quickest way to install psycopg is using the wheel_ package available on PyPI_:
.. code-block:: console
$ pip install psycopg2-binary
This will install a pre-compiled binary version of the module which does not require the build or runtime prerequisites described below. Make sure to sue an up-date-date version of :program:`pip` (you can upgrade it
using something like ``pip install -U pip``).
You may then import the ``psycopg`` package, as usual:
.. code-block:: python
import psycopg
# Connect to your postgres DB
conn = psycopg.connect("dbname=test user=postgres")
# Open a cursor to perform database operations
cur = conn.cursor()
# Execute a query
cur.execute("SELECT * FROM my_data");
# Retrieve query results
records = cur.fetchall()
.. __: PyPI-binary_
.. _PyPI: https://pypi.org/project/psycopg2-binary/
.. _wheel: https://pythonwheels.com/
psycopg vs psycopg-binary
^^^^^^^^^^^^^^^^^^^^^^^^^
The ``psycopg2-binary`` package is meant for beginners to start playing
with Python and PostgreSQL without the need to meet the build
requirements.
If you are the maintainer of a published package depending on `!psycopg2`
you shouldn't use 'psycopg2-binary' as a module dependency. **For
production use you are advised to use the source distribution.**
The binary packages come with their own versions of a few C libraries,
among which ``libpq`` and ``libssl``, which will be used regardless of other
libraries available on the client: upgrading the system libraries will not
upgrade the libraries used by `!psycopg2`. Please build `!psycopg2` from
source if you want to maintain binary upgradeability.
.. warning::
The `!psycopg2` wheel package comes packaged, among the others, with its
own ``libssl`` binary. This may create conflicts with other extension
modules binding with ``libssl`` as well, for instance with the Python
`ssl` module: in some cases, under concurrency, the interaction between
the two libraries may result in a segfault. In case of doubts you are
advised to use a package built from source.
.. index::
single: Install; disable wheel
single: Wheel; disable
.. _disable-wheel:
Change in binary packages between Psycopg 2.7 and 2.8
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
In version 2.7.x, :command:`pip install psycopg2` would have tried to install
automatically the binary package of Psycopg. Because of concurrency problems
binary packages have displayed, ``psycopg2-binary`` has become a separate
package, and from 2.8 it has become the only way to install the binary
package.
If you are using Psycopg 2.7 and you want to disable the use of wheel binary
packages, relying on the system libraries available on your client, you
can use the :command:`pip` |--no-binary option|__, e.g.:
.. code-block:: console
$ pip install --no-binary :all: psycopg2
.. |--no-binary option| replace:: ``--no-binary`` option
.. __: https://pip.pypa.io/en/stable/reference/pip_install/#install-no-binary
which can be specified in your :file:`requirements.txt` files too, e.g. use:
.. code-block:: none
psycopg2>=2.7,<2.8 --no-binary psycopg2
to use the last bugfix release of the `!psycopg2` 2.7 package, specifying to
always compile it from source. Of course in this case you will have to meet
the :ref:`build prerequisites <build-prerequisites>`.
.. index:: .. index::
single: Prerequisites single: Prerequisites
@ -131,97 +220,6 @@ which is OS-dependent (for instance setting a suitable
.. index::
single: Install; from PyPI
single: Install; wheel
single: Wheel
.. _binary-packages:
Binary install from PyPI
------------------------
`!psycopg2` is also `available on PyPI`__ in the form of wheel_ packages for
the most common platform (Linux, OSX, Windows): this should make you able to
install a binary version of the module, not requiring the above build or
runtime prerequisites.
.. note::
The ``psycopg2-binary`` package is meant for beginners to start playing
with Python and PostgreSQL without the need to meet the build
requirements.
If you are the maintainer of a published package depending on `!psycopg2`
**you shouldn't use 'psycopg2-binary' as a module dependency**. For
production use you are advised to use the source distribution.
Make sure to use an up-to-date version of :program:`pip` (you can upgrade it
using something like ``pip install -U pip``), then you can run:
.. code-block:: console
$ pip install psycopg2-binary
.. __: PyPI-binary_
.. _PyPI-binary: https://pypi.org/project/psycopg2-binary/
.. _wheel: https://pythonwheels.com/
.. note::
The binary packages come with their own versions of a few C libraries,
among which ``libpq`` and ``libssl``, which will be used regardless of other
libraries available on the client: upgrading the system libraries will not
upgrade the libraries used by `!psycopg2`. Please build `!psycopg2` from
source if you want to maintain binary upgradeability.
.. warning::
The `!psycopg2` wheel package comes packaged, among the others, with its
own ``libssl`` binary. This may create conflicts with other extension
modules binding with ``libssl`` as well, for instance with the Python
`ssl` module: in some cases, under concurrency, the interaction between
the two libraries may result in a segfault. In case of doubts you are
advised to use a package built from source.
.. index::
single: Install; disable wheel
single: Wheel; disable
.. _disable-wheel:
Change in binary packages between Psycopg 2.7 and 2.8
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
In version 2.7.x, :command:`pip install psycopg2` would have tried to install
automatically the binary package of Psycopg. Because of concurrency problems
binary packages have displayed, ``psycopg2-binary`` has become a separate
package, and from 2.8 it has become the only way to install the binary
package.
If you are using Psycopg 2.7 and you want to disable the use of wheel binary
packages, relying on the system libraries available on your client, you
can use the :command:`pip` |--no-binary option|__, e.g.:
.. code-block:: console
$ pip install --no-binary :all: psycopg2
.. |--no-binary option| replace:: ``--no-binary`` option
.. __: https://pip.pypa.io/en/stable/reference/pip_install/#install-no-binary
which can be specified in your :file:`requirements.txt` files too, e.g. use:
.. code-block:: none
psycopg2>=2.7,<2.8 --no-binary psycopg2
to use the last bugfix release of the `!psycopg2` 2.7 package, specifying to
always compile it from source. Of course in this case you will have to meet
the :ref:`build prerequisites <build-prerequisites>`.
@ -286,6 +284,29 @@ order to create a debug package:
.. __: https://pypi.org/project/psycopg2/#files .. __: https://pypi.org/project/psycopg2/#files
Non-standard Python Implementation
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The `psycopg2` package is the current mature implementation of the adapter: it
is a C extension and as such it is only compatible with CPython_. If you want
to use Psycopg on a different Python implementation (PyPy, Jython, IronPython)
there is a couple of alternative:
- a `Ctypes port`__, but it is not as mature as the C implementation yet
and it is not as feature-complete;
- a `CFFI port`__ which is currently more used and reported more efficient on
PyPy, but please be careful of its version numbers because they are not
aligned to the official psycopg2 ones and some features may differ.
.. _PostgreSQL: https://www.postgresql.org/
.. _Python: https://www.python.org/
.. _libpq: https://www.postgresql.org/docs/current/static/libpq.html
.. _CPython: https://en.wikipedia.org/wiki/CPython
.. _Ctypes: https://docs.python.org/library/ctypes.html
.. __: https://github.com/mvantellingen/psycopg2-ctypes
.. __: https://github.com/chtd/psycopg2cffi
.. index:: .. index::
single: tests single: tests