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From: Nathan Bossart <nathandbossart@gmail.com>
To: Sami Imseih <samimseih@gmail.com>
Cc: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: Improve LWLock tranche name visibility across backends
Date: Tue, 15 Jul 2025 11:57:31 -0500
Message-ID: <aHaIe44bAENt8JPW@nathan> (raw)
In-Reply-To: <CAA5RZ0sjBirbsZa0su1yV2UEQFcVmy-HkeQNS+SD5oAxQaRYPQ@mail.gmail.com>
References: <aG9/OKQRgPUCxmsX@ip-10-97-1-34.eu-west-3.compute.internal>
	<CAA5RZ0ui5+=Q3ouxbrjSKa1xJvOjDD2tNYfkG-UtJJNNc-4E=g@mail.gmail.com>
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	<CAA5RZ0uic7Us255mFPJSrMFH7UY-RR8YZcjBzNDzfE4gFREDGQ@mail.gmail.com>
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	<aHV5BsKoSeOkIsNL@nathan>
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On Tue, Jul 15, 2025 at 11:52:19AM -0500, Sami Imseih wrote:
>> Another random thought: I worry that the dshash approach might be quite a
>> bit slower, and IIUC we just need to map an integer to a string.  Maybe we
>> should just use a DSA for LWLockTrancheNames. IOW we'd leave it as a char**
>> but put it in shared memory.
> 
> To use DSA just for this purpose, we would need to maintain an array of
> dsa_pointers that reference the string(s), right? I am not clear what you
> mean by using dsa to put the char**

I was imagining putting the array in one big DSA allocation instead of
carting around a pointer for each tranche name.  (Sorry, I realize I am
hand-waving over some of the details.)

-- 
nathan





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