Re: mod_cache and mod_mem_cache

[Manik Taneja <mtaneja@xxxxxxxxx>]

Hi,

This requires some amount of development work. We added an additional 
header to the response header, X-Cache-Stat.  In file mod_cache.c, the 
following changes were made. The actual line numbers may differ 
depending on your version of the code.


465a477,480
>         /*mbenjamin: TCP_MISS*/
>         if (!apr_table_get(r->headers_out, "X-CacheStat"))
>             apr_table_setn(r->headers_out, "X-CacheStat", 
"TCP_MISS_VERIFY");
>
492a508,511
>         /*mbenjamin: TCP_MISS*/
>         if (!apr_table_get(r->headers_out, "X-CacheStat"))
>             apr_table_setn(r->headers_out, "X-CacheStat", 
"TCP_MISS_NOSTORE");
>
503c522,526
<     }
---
>             /*mbenjamin: TCP_MISS*/
>         if (!apr_table_get(r->headers_out, "X-CacheStat"))
>             apr_table_setn(r->headers_out, "X-CacheStat", 
"TCP_MISS_PRIVATE");
>
> }
514a538,541
>         /*mbenjamin: TCP_MISS*/
>         if (!apr_table_get(r->headers_out, "X-CacheStat"))
>             apr_table_setn(r->headers_out, "X-CacheStat", 
"TCP_MISS_AUTH_FAILED");
>
530a558,560
>         /*mbenjamin: TCP_MISS*/
>         if (!apr_table_get(r->headers_out, "X-CacheStat"))
>             apr_table_setn(r->headers_out, "X-CacheStat", "TCP_MISS");
606a637
>
607a639,647
>             /*mbenjamin: TCP_HIT_VERIFY*/
>             if(!apr_table_get(r->headers_out, "X-CacheStat")) {
>             if(strstr("mem", cache->provider_name)) {
>                        apr_table_setn(r->headers_out, "X-CacheStat", 
"TCP_HIT_VERIFY_MEM");
>             }else{
>                        apr_table_setn(r->headers_out, "X-CacheStat", 
"TCP_HIT_VERIFY_DISK");
>                     }
>                 }
>
621a662,664
>             /*mbenjamin: TCP_MISS_VERIFY*/
>             apr_table_setn(r->headers_out, "X-CacheStat", 
"TCP_MISS_VERIFY");
>
629a673,677
>
>         /*mbenjamin: TCP_MISS*/
>     if (!apr_table_get(r->headers_out, "X-CacheStat"))
>             apr_table_setn(r->headers_out, "X-CacheStat", "TCP_MISS");
>

Then as a final step you configure the access log format in httpd.conf 
to log the value of the X-CacheStat header.

hope this helps.

Thanks,
Manik

Andrew Dixon wrote:
> Hi Manik,
>
> Can you explain how you did this?
>
> Thanks
>
> Andrew
>
> 2008/11/5 Manik Taneja <mtaneja@xxxxxxxxx <mailto:mtaneja@xxxxxxxxx>>
>
>     Andrew Dixon wrote:
>
>         Hi All,
>
>         I have enabled mod_cache and I'm using mem caching
>         (mod_mem_cache) as my caching type, but how can I check if it
>         is actually doing anything. Is there anyway to see what is in
>         the cache, being served from the cache, what the cache hit
>         rate is, etc...???
>
>     There isn't a way, at least as of apache 2.2.9. <http://2.2.9.> We
>     had a similar problem but i modified the status code that gets
>     logged to apache logs to indicate is the 200OK/302 was a result of
>     a cache-hit.
>     -M
>
>         Thanks
>
>         Kind regards,
>
>         Andrew.
>
>
>
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