Re: Patch proposal: New hooks in the connection path

bdrouvotAWS <bdrouvot@amazon.com>

From: "Drouvot, Bertrand" <bdrouvot@amazon.com>

To: Tom Lane <tgl@sss.pgh.pa.us>, Joe Conway <mail@joeconway.com>

Cc: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Nathan Bossart <nathandbossart@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>

Date: 2022-08-08T10:51:20Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Add pg_stat_database counters for sessions and session time
- 960869da0803 14.0 cited

Attachments

v2-0004-connection_hooks.patch (text/plain) patch v2-0004

Hi,

On 7/12/22 2:58 PM, Drouvot, Bertrand wrote:
> Hi,
>
> On 7/11/22 8:18 AM, Drouvot, Bertrand wrote:
>> Hi,
>>
>> The use case would be to increment a counter in shared memory (or 
>> most probably within an hash table) to reflect the number of times a 
>> startup packet timeout occurred.
>>
>> Reading the comments in/related to BackendInitialize() I understand 
>> that's definitely not safe to write in shared memory for the 
>> EXEC_BACKEND case, but wouldn't it be safe for the non EXEC_BACKEND 
>> case?
>>
>> BTW, it makes me realize that the hook being fired in the bad startup 
>> packet case:
>>
>>         /*
>>          * Stop here if it was bad or a cancel packet. 
>> ProcessStartupPacket
>>          * already did any appropriate error reporting.
>>          */
>>         if (status != STATUS_OK)
>> +       {
>> +               if (FailedConnection_hook)
>> +                       (*FailedConnection_hook) 
>> (FCET_BAD_STARTUP_PACKET, port);
>>                 proc_exit(0);
>> +       }
>>
>> is not safe for the EXEC_BACKEND case.
>>
> What about the idea to trigger the hook for the STARTUP PACKET TIMEOUT 
> and BAD STARTUP PACKET only for the non EXEC_BACKEND/Windows cases?
>
> I'm tempted to think it's better to have some cases where one could 
> benefit from the hook as opposed to none.
>
> Thoughts?

Please find attached v2-0004-connection_hooks.patch as an attempt of 
doing so.

Thanks

-- 
Bertrand Drouvot
Amazon Web Services: https://aws.amazon.com