Re: Listen/Notify feedback

From: Rita <rmorgan466(at)gmail(dot)com>
To: Brian Dunavant <dunavant(at)gmail(dot)com>
Cc: "pgsql-general(at)postgresql(dot)org >> PG-General Mailing List" <pgsql-general(at)postgresql(dot)org>
Subject: Re: Listen/Notify feedback
Date: 2020-07-12 11:39:09
Message-ID: CAOF-KfhEQ-Pqbw6TCRt-4bNAAs0iLR1FQz2b7qmBVbVFae57bA@mail.gmail.com
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Thats good to know. Are there some standard patterns or best practices I
should follow when using messaging and with listen/notify?

On Sat, Jul 11, 2020 at 1:44 PM Brian Dunavant <dunavant(at)gmail(dot)com> wrote:

> One aspect is if there is no one listening when a notify happens, the
> message is lost (e.g. no durability). If this is important to you, it can
> be addressed by writing the messages to a table as well when you NOTIFY,
> and the listener deletes messages after they are processed. On connection
> the listener can query the table to catch up on any missed messages, or
> messages that were mid-process during a crash. This is trickier with more
> than one listener. This isn't a whole lot more efficient than just using
> the table alone, but it saves you from having to poll so better response
> times.
>
> On Sat, Jul 11, 2020 at 8:58 AM Rita <rmorgan466(at)gmail(dot)com> wrote:
>
>> I am investigating various pub/sub tools such as ActiveMQ, Rabbit, Redis,
>> etc.I came across Postgresql Listen/Notify and was easily able to write
>> code to listen to messages. For the people who have been using this for a
>> while: what are its downsides, things to consider when writing good code
>> that use pub/sub, how do you deal with large messages, can I have
>> subscribers listen to replica nodes?
>>
>> Thanks
>> --
>> --- Get your facts first, then you can distort them as you please.--
>>
>

--
--- Get your facts first, then you can distort them as you please.--

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