[pgpool-hackers: 2650] Pgpool-II 3.8: allow to specify load balance weight ratio for load balance parameters

Tatsuo Ishii ishii at sraoss.co.jp
Thu Dec 14 13:55:52 JST 2017


Currently we can specify load balance condition by using,
database_redirect_preference_list, and
app_name_redirect_preference_list like:

postgres:primary

This means, if connected database is postgres, every SELECTs will be
redirected to primary.

It would be nice if we could specify load balance ratio like:

postgres:primary(0.3)

which redirects 30% of SELECTs to primary (that is, other 70% of
SELECTs will be redirected to the load balance node). If the primary
node is also the load balance node, 100% of SELCTs will be redirected
to the primary.

Other example is:

postgres:primary(0.0)

which never redirects SELECTs to the primary. This is useful if user
never wants to redirect SELECTs on the primary. Actually we cannot do
this for now if a primary node changes time to time.

postgres:mydb[0-4]:1(0.3)

which redirects 30% of SELECTs to node 1 (that is, other 70% of
SELECTs will be redirected to the load balance node). If node 1 is
also the load balance node, 100% of SELCTs will be redirected to node
1.

I suppose the new specification overrides the current "weight"
parameters for each node.

Comments and suggestions are welcome.
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp


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