[Pdns-dev] Question regarding life time of backend threads in PDNS

[Seema Datar]

Hi All,

Does anybody have more information on this?

Thanks,
Seema

From: Seema Datar <sdatar at yahoo-inc.com<mailto:sdatar at yahoo-inc.com>>
Date: Thursday, November 7, 2013 10:49 AM
To: "pdns-users at mailman.powerdns.com<mailto:pdns-users at mailman.powerdns.com>" <pdns-users at mailman.powerdns.com<mailto:pdns-users at mailman.powerdns.com>>, "pdns-dev at mailman.powerdns.com<mailto:pdns-dev at mailman.powerdns.com>" <pdns-dev at mailman.powerdns.com<mailto:pdns-dev at mailman.powerdns.com>>
Subject: Question regarding life time of backend threads in PDNS

Hi All,

We have a use case where we use PDNS with 8 backend threads. We needed to save thread specific data in an mmap. However, I came across the following in PDNS documentation -

PowerDNS may instantiate multiple instances of your backend, or destroy existing copies and instantiate new ones. Backend code should therefore be thread-safe with respect to its static data. Additionally, it is wise if instantiation is a fast operation, with the possible exception of the first construction.

The questions I had are -


  1.  What is the lifetime of a backend thread?
  2.  How often does a thread get destroyed and a new  thread get created?
  3.  Is there any interface available to do a cleanup before the thread ends?

Thanks,
Seema
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