[pgpool-committers: 2707] Re: pgpool: Mega patch to enhance performance in extended protocol mode.

[Tatsuo Ishii]

Sorry my bad. I have committed CommandComplete.c.

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp

> Ishii-san,
> 
> Is this commit missing CommandComplete.c?
> 
> 
> On Thu, 24 Sep 2015 02:13:16 +0000
> Tatsuo Ishii <ishii at postgresql.org> wrote:
> 
>> Mega patch to enhance performance in extended protocol mode.
>> 
>> For now it only affects to streaming replication mode, that is, the
>> performance of other modes remains same. In the future we may be able
>> to enhance this.
>> 
>> Anyway, basic idea here is, removing "flush" message which used to be
>> sent in each step of extended protocol messages (parse, bind, describe
>> and execute). This brought significant communication overhead. To
>> achieve the goal following modifications have been made.
>> 
>> - New data structure called "pending message queue" is created to
>>   manage which response of particular message is pending.  When
>>   Parse/Bind/Close message are received, each message is en-queued.
>>   The information is used to process those response messages, when
>>   Parse complete/Bind completes and Close compete message are received
>>   because they don't have any information regarding statement/portal.
>> 
>> - New state variable to represent that there's any "pending response"
>>   exists. If an extended protocol message, for example, parse is sent
>>   and still the response to parse (i.e. parse complete) is not yet
>>   received, the variable is set to true.
>> 
>> - If there's any pending response, do_query() sends flush message to
>>   retrieve any pending data from primary backend and save it. After
>>   finishing the job, the saved data is restored. This will keep the
>>   original response message sequence.
>> 
>> - Deal with a special case in read_kind_from_backend(). Certain client
>>   (at least JDBC driver has this habit) does not send a sync message
>>   after an execute message. See the comment in
>>   read_kind_from_backend() for more details.
>> 
>> - New data structure called "sync map" to manage sync message response
>>   is added.  Used for managing sync message response in streaming
>>   replication mode. In streaming replication mode, there are at most
>>   two nodes involved. One is always primary, and the other (if any)
>>   could be standby. If the load balancing manager chooses the primary
>>   as the load balancing node, only the primary node is involved. Every
>>   time extended protocol is sent to backend, we set true on the member
>>   of array below. It is cleared after sync message is processed and
>>   command complete or error response message is processed.
>> 
>> - New parameter "bool nowait" is added to
>>   pool_extended_send_and_wait() to control whether flush message is
>>   sent or not after sending extended protocol command.
>> 
>> - Move CommandComplete() to new file src/protocol/CommandComplete.c to
>>   make maintainer's life easier.
>> 
>> Initial performance evaluation:
>> 
>> - Hard ware: Let's note CF-SX3, mem 16GB, SSD 512GB, Core i7-4600U (2 cores)
>> - OS: Ubuntu 14.04 LTS
>> - 2 PostgreSQL streaming replication setup using pgpool_setup
>> - pgbench options: pgbench -M extended -c 16 -j 8 -S -T 30 test (scale=1)
>> - Results (excluding connections establishing):
>>   pgpool-II 3.4.4: 7274.926104 TPS, this commit: 11290.026468 TPS
>>   So, this committed version is 55.2% faster than 3.4.3.
>> 
>> TODOs:
>> - parse_before_bind() in pool_proto_modules is ifdef'ed out. Even
>>   without this, all regression tests are passed. But I am not sure if
>>   it's really harmless.
>> 
>> - When parse message is sent, it is possible that deadlock occurs
>>   according to the comment. I'm not sure if it's still true or not. If
>>   true, we need to fix it.
>> 
>> Branch
>> ------
>> master
>> 
>> Details
>> -------
>> http://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=e7b4de8d457e223234975b4ceaf8c345acdc2492
>> 
>> Modified Files
>> --------------
>> src/Makefile.am                                    |    3 +-
>> src/Makefile.in                                    |    7 +-
>> src/context/pool_query_context.c                   |   82 +++--
>> src/context/pool_session_context.c                 |  295 +++++++++++++++-
>> src/include/context/pool_query_context.h           |    2 +-
>> src/include/context/pool_session_context.h         |   63 ++++
>> src/include/pool.h                                 |    1 +
>> src/include/protocol/pool_proto_modules.h          |    5 +
>> src/protocol/pool_process_query.c                  |  282 +++++++++++++--
>> src/protocol/pool_proto_modules.c                  |  372 +++++++-------------
>> src/query_cache/pool_memqcache.c                   |  192 +++++++---
>> .../regression/tests/006.memqcache/jdbctest.java   |    2 +-
>> src/test/regression/tests/051.bug60/test.sh        |    6 +-
>> src/utils/pool_stream.c                            |   54 ++-
>> 14 files changed, 983 insertions(+), 383 deletions(-)
>> 
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>> pgpool-committers at pgpool.net
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> 
> 
> -- 
> Yugo Nagata <nagata at sraoss.co.jp>