pg-batch 1.1.1
Run large PostgreSQL UPDATE and DELETE queries with small batches to prevent locks
License: MIT

pg-batch
========

|Pypi| |Build Status| |codecov| |MIT licensed|

PostgreSQL equivalent of https://github.com/gabfl/mysql-batch.

Updating or deleting a large amount of rows in PostgreSQL will create
locks that will paralyze other queries running in parallel.

This tool will run UPDATE and DELETE queries in small batches to limit
locking. If a large number of rows has to be updated or deleted, it is
also possible to limit the number of rows selected at once.

Installation
------------

::

   pip3 install pg_batch

UPDATE example
--------------

You can run this example with the schema available in
`sample_table/schema.sql <sample_table/schema.sql>`__

The following example will be identical to the following update:

.. code:: sql

   UPDATE batch_test SET date = NOW() WHERE number > 30 AND date is NULL;

This is the equivalent to process this update with batches of 20 rows:

.. code:: bash

   pg_batch --host localhost \
            --user postgres \
            --password secret_password \
            --database "test" \
            --table "batch_test" \
            --write_batch_size 20 \
            --where "number > 30 AND date IS NULL" \
            --set "date = NOW()"

Output sample:

.. code:: bash

   * Selecting data...
      query: SELECT id as id FROM batch_test WHERE number > 30 AND date IS NULL AND id > 0 ORDER BY id LIMIT 10000
   * Preparing to modify 70 rows...
   * Updating 20 rows...
      query: UPDATE batch_test SET date = NOW() WHERE id IN (31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50)
   * Start updating? [Y/n]
   * Updating 20 rows...
      query: UPDATE batch_test SET date = NOW() WHERE id IN (51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70)
   * Updating 20 rows...
      query: UPDATE batch_test SET date = NOW() WHERE id IN (71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90)
   * Updating 10 rows...
      query: UPDATE batch_test SET date = NOW() WHERE id IN (91, 92, 93, 94, 95, 96, 97, 98, 99, 100)
   * Selecting data...
      query: SELECT id as id FROM batch_test WHERE number > 30 AND date IS NULL AND id > 100 ORDER BY id LIMIT 10000
   * No more rows to modify!
   * Program exited

DELETE example
--------------

The following example will be identical to the following delete:

.. code:: sql

   DELETE FROM batch_test WHERE number > 30 AND date is NULL;

This is the equivalent to process this delete with batches of 20 rows:

.. code:: bash

   pg_batch --host localhost \
            --user postgres \
            --password secret_password \
            --database "test" \
            --table "batch_test" \
            --write_batch_size 20 \
            --where "number > 30 AND date IS NULL" \
            --action "delete"

Output sample:

.. code:: bash

   * Selecting data...
      query: SELECT id as id FROM batch_test WHERE number > 30 AND date IS NULL AND id > 0 ORDER BY id LIMIT 10000
   * Preparing to modify 70 rows...
   * Deleting 20 rows...
      query: DELETE FROM batch_test WHERE id IN (31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50)
   * Start deleting? [Y/n]
   * Deleting 20 rows...
      query: DELETE FROM batch_test WHERE id IN (51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70)
   * Deleting 20 rows...
      query: DELETE FROM batch_test WHERE id IN (71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90)
   * Deleting 10 rows...
      query: DELETE FROM batch_test WHERE id IN (91, 92, 93, 94, 95, 96, 97, 98, 99, 100)
   * Selecting data...
      query: SELECT id as id FROM batch_test WHERE number > 30 AND date IS NULL AND id > 100 ORDER BY id LIMIT 10000
   * No more rows to modify!
   * Program exited

Usage
-----

.. code:: bash

   usage: pg_batch [-h] [-H HOST] [-P PORT] -U USER [-p PASSWORD] -d DATABASE -t
                   TABLE [-id PRIMARY_KEY] -w WHERE [-s SET]
                   [-rbz READ_BATCH_SIZE] [-wbz WRITE_BATCH_SIZE] [-S SLEEP]
                   [-a {update,delete}] [-n]

   optional arguments:
     -h, --help            show this help message and exit
     -H HOST, --host HOST  PostgreSQL server host
     -P PORT, --port PORT  PostgreSQL server port
     -U USER, --user USER  PostgreSQL user
     -p PASSWORD, --password PASSWORD
                           PostgreSQL password
     -d DATABASE, --database DATABASE
                           PostgreSQL database name
     -t TABLE, --table TABLE
                           PostgreSQL table
     -id PRIMARY_KEY, --primary_key PRIMARY_KEY
                           Name of the primary key column
     -w WHERE, --where WHERE
                           Select WHERE clause
     -s SET, --set SET     Update SET clause
     -rbz READ_BATCH_SIZE, --read_batch_size READ_BATCH_SIZE
                           Select batch size
     -wbz WRITE_BATCH_SIZE, --write_batch_size WRITE_BATCH_SIZE
                           Update/delete batch size
     -S SLEEP, --sleep SLEEP
                           Sleep after each batch
     -a {update,delete}, --action {update,delete}
                           Action ('update' or 'delete')
     -n, --no_confirm      Don't ask for confirmation before to run the write
                           queries

License
-------

This program is under MIT license (`view license <LICENSE>`__).

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   :target: https://pypi.org/project/pg-batch
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   :target: https://github.com/gabfl/pg-batch/actions
.. |codecov| image:: https://codecov.io/gh/gabfl/pg-batch/branch/main/graph/badge.svg
   :target: https://codecov.io/gh/gabfl/pg-batch
.. |MIT licensed| image:: https://img.shields.io/badge/license-MIT-green.svg
   :target: https://raw.githubusercontent.com/gabfl/pg-batch/main/LICENSE