[pgpool-hackers: 2649] Re: Load-balancing control for specific queries

Tatsuo Ishii ishii at sraoss.co.jp
Thu Dec 14 10:25:10 JST 2017


>>> >> > We can think of at least two possible designs for this feature.
>>> >> > 
>>> >> > (1) Defining blacklist
>>> >> > 
>>> >> > Like black_function_list, specifying queries not to be load-balanced.
>>> >> > 
>>> >> > (2) Specifiying desitination nodes
>>> >> > 
>>> >> > Like database_redirect_preference_list, specify pairs of queries and node id
>>> >> > (or primary/standby).
>>> >> > 
>>> >> > In both cases, the target queries can be specified by regexp pettern or tables
>>> >> > included in the queries. (The client's preference is using regexp.)
>> 
>> By the way, which of above design do you like better? I think 2) Specifiying desitination
>> nodes with using regexp is good because it is the most general among the above, and
>> this design covers all cases that other designs can cover.
> 
> #2 is better I think.
> 
> BTW, it would be hard to allow node id be specified in the parameter
> however (primary or standby is ok). Because after connection between
> client and Pgpool-II is established, the load balance node is already
> defined, which is either primary or one of standbys. If it is allowed
> to specify other than primar or such standby, it will require major
> rewriting of the load balance code because it currently only handles
> the primary node and one standby node (the load balance node).

I have added this to the TODO list.

http://www.pgpool.net/mediawiki/index.php/TODO#Allow_to_choose_load_balance_behavior_per_SQL_statement

Best regards,
--
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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