Re: [squid-users] swap.state question

From: Henrik Nordstrom <>
Date: Sat, 28 Feb 2004 00:45:04 +0100 (CET)

On Fri, 27 Feb 2004, OTR Comm wrote:

> Could someone explain the relationship between the swap.state file and
> the actual files in the L2 directories?

swap.state contains an index and combined transaction log over which
objects are cached where in the L2 directories.

> Is the swap.state a database where Squid does it's cache checking and
> the L2 directory files where the data is presented from?


> Also, if one of the cache files is deleted, does the swap.state maintain
> information about that file?

Yes, but Squid automatically recovers when encountering the mismatch.

> I am trying to understand how purging items from the cache works, and
> realize that has to be some relationship between swap.state and the L2
> files

Actually not.. purging operates at a higher level and results in the L2
file to be deleted and a delete operation to be logged in swap.state.

> but I looked in the code for client.c (ver 2.5) and
> (ver 3.0) and can not figure out where swap.state or the L2 files are
> addressed.

The squidclient program just sends a HTTP request to Squid asking it to
purge the file. It does not touch the cache directly.

It is only Squid himself which modifies the cache files.

Received on Fri Feb 27 2004 - 17:13:54 MST

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