[pgpool-hackers: 2240] Re: [pgpool-committers: 3836] pgpool: Branch refs/heads/bug271 was created

[Sergey Kim]

Tatsuo,


the symptoms of the "hanged" pgpool are following:
1) DB applications fail with 2 types of errors:
  - failed to prepare statement (PARSE)
  - failed to extract ResultSet - failed selects

2) The problem is reproduced within a single JDBC connection, series of transactions are passed into it before the problem appears.

I'm deeply analysed pgpool logs from the series of failures and revealed a sample case (i.e. pgpool process). It's logs are attached.
I'm not sure I'm right but it seems the balancing logic is broken it its sequence of messages - how the are processed. I'am triggered by the fact it was sending PARSE messages to the both backends.

P/S: I was trying to attach the debugger to pgpool but I'm failed to detect a piece of code which I should focus at. Also it is a little bit hard to detect a pgpool process which should be debugged.

Sergey.
________________________________
From: Sergey Kim
Sent: Wednesday, April 5, 2017 1:48 PM
To: Tatsuo Ishii
Cc: Boris Voskanov; pgpool-hackers at pgpool.net; Sergey Onuchin
Subject: Re: [pgpool-hackers: 2227] Re: [pgpool-committers: 3836] pgpool: Branch refs/heads/bug271 was created


... also it happens only when balancing is enabled in pgpool.


________________________________
From: Sergey Kim
Sent: Wednesday, April 5, 2017 1:34:45 PM
To: Tatsuo Ishii
Cc: Boris Voskanov; pgpool-hackers at pgpool.net; Sergey Onuchin
Subject: Re: [pgpool-hackers: 2227] Re: [pgpool-committers: 3836] pgpool: Branch refs/heads/bug271 was created


Tatsuo,


the 2nd day of tests revealed a problem in pgpool which I trying to reproduce in a standalone test.


Sometimes PARSE messages hang in pgpool and DB clients hang due to this reason. I'm just wanted to notify you on the problem. I'm fighting to reproduce it artificially.


Sergey.


...the primary message was cut
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