
= queue_mover(1) =

== NAME ==

queue_mover - PgQ consumer that copies data from one queue to another.

== SYNOPSIS ==

  queue_mover.py [switches] config.ini 

== DESCRIPTION ==

queue_mover is PgQ consumer that transports events from source queue into 
target queue. One use case is when events are produced in several databases 
then queue_mover is used to consolidate these events into single queue
that can then be processed by consumers who need to handle theses events.
For example in case of patitioned databases it's convenient to move events
from each partition into one central queue database and then process them there.
That way configuration and dependancies of partiton databases are 
simpler and more robust. Another use case is to move events from OLTP 
database to batch processing server.

Transactionality: events will be inserted as one transaction on target side.
That means only batch_id needs to be tracked on target side.

== QUICK-START ==

Basic PgQ setup and usage can be summarized by the following
steps:

  1. PgQ must be installed both in source and target databases.
     See pgqadm man page for details.

  2. Target database must also have pgq_ext schema installed.
     It is used to keep sync between two databases.

  3. Create a queue_mover configuration file, say qmover_sourceq_to_targetdb.ini

  4. create source and target queues 

     $ pgqadm.py sourcedb_ticker.ini create <srcqueue>
     $ pgqadm.py targetdb_ticker.ini create <dstqueue>

  5. launch queue mover in daemon mode

     $ queue_mover.py -d qmover_sourceq_to_targetdb.ini

  6. start producing and consuming events 


== CONFIG ==

include::common.config.txt[]

=== queue_mover parameters ===

src_db::
  Source database.

dst_db::
  Target database.

dst_queue_name::
  Target queue name.

=== Example config file ===

  [queue_mover]
  job_name = eventlog_to_target_mover
  src_db = dbname=sourcedb
  dst_db = dbname=targetdb
  pgq_queue_name = eventlog
  dst_queue_name = copy_of_eventlog
  pidfile = log/%(job_name)s.pid
  logfile = pid/%(job_name)s.log
  
== COMMAND LINE SWITCHES ==

include::common.switches.txt[]

== BUGS ==

Event ID is not kept on target side.  If needed is can be kept,
then event_id seq at target side need to be increased by hand to
inform ticker about new events.

