streampq

Stream results of multi-statement PostgreSQL queries from Python without server-side cursors. Has benefits over some other Python PostgreSQL libraries:

Streams results from complex multi-statement queries even though SQL doesn't allow server-side cursors for such queries - suitable for large amounts of results that don't fit in memory.
CTRL+C (SIGINT) by default behaves as expected even during slow queries - a KeyboardInterrupt is raised and quickly bubbles up through streampq code. Unless client code prevents it, the program will exit.
Every effort is made to cancel queries on KeyboardInterrupt, SystemExit, or errors - the server doesn't continue needlessly using resources.

Installation

pip install streampq

The libpq binary library is also required. This is typically either already installed, or installed by:

macOS + brew: brew install libpq
Linux (Debian): apt install libpq5
Linux (Red Hat):yum install postgresql-libs

Usage

from streampq import streampq_connect

# libpq connection paramters
# https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-PARAMKEYWORDS
#
# Any can be ommitted and environment variables will be used instead
# https://www.postgresql.org/docs/current/libpq-envars.html
connection_params = (
    ('host', 'localhost'),
    ('port', '5432'),
    ('dbname', 'postgres'),
    ('user', 'postgres'),
    ('password', 'password'),
)

# SQL statement(s) - if more than one, separate by ;
sql = '''
SELECT * FROM my_table WHERE my_col = {first};
SELECT * FROM my_other_table WHERE my_other_col = {second};
'''

with streampq_connect(connection_params) as query:
    for (columns, rows) in query(sql, literals=(
        ('first', 'a value'),
        ('second', 'another value'),
    )):
        for row in rows:
            pass

Exceptions

Exceptions derive from streampq.StreamPQError. If there is any more information available on the error, it's added as a string in its args property. This is included in the string representation of the exception by default.

Exception hierarchy

StreamPQError

Base class for all explicitly-thrown exceptions
- ConnectionError
  
  An error occurred while attempting to connect to the database.
- QueryError
  
  An error occurred while attempting to run a query. Typically this is due to a syntax error or a missing column.
- CancelError
  
  An error occurred while attempting to cancel a query.
- CommunicationError
  
  An error occurred communicating with the database after successful connection.

Release files for streampq 0.0.11

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Source distribution (sdist)

Source distribution for streampq 0.0.11
File	Size	Uploaded
streampq-0.0.11.tar.gz	6.0 kB	Apr 9, 2022	Details

Built distribution (wheel)

Table of built distributions (wheels) for streampq 0.0.11
File	Interpreter	ABI	Platform	Reset
streampq-0.0.11-py3-none-any.whl 6.3 kB Apr 9, 2022	Python 3	none	any	Details

Total release size: 12.3 kB

Release files / streampq-0.0.11.tar.gz

Download URL	streampq-0.0.11.tar.gz
Size	6.0 kB
Tags	Source
SHA-256 checksum How to use checksums	`e9b46d4e02654bc7ef8663ed8586aeb0bc6b8546f46f24447701fb2be263c57b`
BLAKE2b-256 checksum How to use checksums	`f19f367ebb3ccf781ea82228fb6ded7f6886dc8154cc721b5686a30f0b07316f`
Upload date	Apr 9, 2022
Uploaded using Trusted Publishing? What is trusted publishing?	No
Uploaded via	`twine/4.0.0 CPython/3.8.11`

Release files / streampq-0.0.11-py3-none-any.whl

Download URL	streampq-0.0.11-py3-none-any.whl
Size	6.3 kB
Tags	Python 3
SHA-256 checksum How to use checksums	`da14d4066e27271c5b5401ef9f7904f8232237a2c2ecdf91b1ae2c6e7faab319`
BLAKE2b-256 checksum How to use checksums	`96422ab625a276a9311754ec27bd9a085c920d4b20e93a1977217a4ae056323c`
Upload date	Apr 9, 2022
Uploaded using Trusted Publishing? What is trusted publishing?	No
Uploaded via	`twine/4.0.0 CPython/3.8.11`