<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:"Lucida Console";
panose-1:2 11 6 9 4 5 4 2 2 4;}
/* Style Definitions */
p.MsoPlainText, li.MsoPlainText, div.MsoPlainText
{mso-style-priority:99;
mso-style-link:"Testo normale Carattere";
margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;
mso-fareast-language:EN-US;}
span.TestonormaleCarattere
{mso-style-name:"Testo normale Carattere";
mso-style-priority:99;
mso-style-link:"Testo normale";
font-family:"Calibri",sans-serif;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri",sans-serif;
mso-fareast-language:EN-US;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:70.85pt 2.0cm 2.0cm 2.0cm;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="IT" link="#0563C1" vlink="#954F72">
<div class="WordSection1">
<p class="MsoPlainText"><span lang="EN-US">>> I mean: squid would store a new copy of the object while leaving the
<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US">>> old copy deletion to cleanup task?<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US">>Some parts of the cleanup process may be delegated.
</span>The details depend on the cache_dir type. <span lang="EN-US">I do not know or remember aufs specifics, but I suspect that all ufs-based cache_dirs, including aufs, use lazy garbage collection >(under normal circumstances).
</span>The cache_swap_low and cache_swap_high directives should determine what is "normal".<o:p></o:p></p>
<p class="MsoPlainText"><span style="color:black"><o:p> </o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black">Alex, you were absolutely right.<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black">I managed to reproduce the case.<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black">On test environment I set up "cache_swap_low 1" and "cache_swap_low 2" and enabled the store_log.<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black">Then I tailed the store_log and watched the evolution of cache_dir, while running squidclient toward origin server every 100ms.<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black"><o:p> </o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black">Store.log:<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="font-size:9.0pt;font-family:"Lucida Console";color:black">1593504359.704 SWAPOUT 00 000098C5 1865A3A26D411E7C0D8D87770720E405 200 1593504359 1593504061 -1 text/plain 544275/544275 GET http://xxx.xxx.xxx.xxx/blah/FEED.json<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="font-size:9.0pt;font-family:"Lucida Console";color:black">1593504359.858 SWAPOUT 00 000098C6 1865A3A26D411E7C0D8D87770720E405 200 1593504359 1593504061 -1 text/plain 544275/544275 GET http://xxx.xxx.xxx.xxx/blah/FEED.json<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="font-size:9.0pt;font-family:"Lucida Console";color:black">1593504360.015 SWAPOUT 00 000098C7 1865A3A26D411E7C0D8D87770720E405 200 1593504359 1593504061 -1 text/plain 544275/544275 GET http://xxx.xxx.xxx.xxx/blah/FEED.json<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="font-size:9.0pt;font-family:"Lucida Console";color:black">1593504360.170 SWAPOUT 00 000098C8 1865A3A26D411E7C0D8D87770720E405 200 1593504359 1593504061 -1 text/plain 544275/544275 GET http://xxx.xxx.xxx.xxx/blah/FEED.json<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="font-size:9.0pt;font-family:"Lucida Console";color:black">1593504360.324 SWAPOUT 00 000098C9 1865A3A26D411E7C0D8D87770720E405 200 1593504359 1593504061 -1 text/plain 544275/544275 GET http://xxx.xxx.xxx.xxx/blah/FEED.json<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="font-size:9.0pt;font-family:"Lucida Console";color:black">1593504360.476 SWAPOUT 00 000098CA 1865A3A26D411E7C0D8D87770720E405 200 1593504359 1593504061 -1 text/plain 544275/544275 GET http://xxx.xxx.xxx.xxx/blah/FEED.json<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="font-size:9.0pt;font-family:"Lucida Console";color:black">1593504360.634 SWAPOUT 00 000098CB 1865A3A26D411E7C0D8D87770720E405 200 1593504360 1593504061 -1 text/plain 544275/544275 GET http://xxx.xxx.xxx.xxx/blah/FEED.json<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="font-size:9.0pt;font-family:"Lucida Console";color:black">1593504360.788 SWAPOUT 00 000098CC 1865A3A26D411E7C0D8D87770720E405 200 1593504360 1593504061 -1 text/plain 544275/544275 GET http://xxx.xxx.xxx.xxx/blah/FEED.json<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="font-size:9.0pt;font-family:"Lucida Console";color:black">1593504360.941 SWAPOUT 00 000098CD 1865A3A26D411E7C0D8D87770720E405 200 1593504360 1593504061 -1 text/plain 544275/544275 GET http://xxx.xxx.xxx.xxx/blah/FEED.json<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="font-size:9.0pt;font-family:"Lucida Console";color:black">1593504361.096 SWAPOUT 00 000098CE 1865A3A26D411E7C0D8D87770720E405 200 1593504360 1593504061 -1 text/plain 544275/544275 GET http://xxx.xxx.xxx.xxx/blah/FEED.json<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="font-size:9.0pt;font-family:"Lucida Console";color:black">1593504361.249 SWAPOUT 00 000098CF 1865A3A26D411E7C0D8D87770720E405 200 1593504360 1593504061 -1 text/plain 544275/544275 GET http://xxx.xxx.xxx.xxx/blah/FEED.json<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="font-size:9.0pt;font-family:"Lucida Console";color:black">1593504361.403 SWAPOUT 00 000098D0 1865A3A26D411E7C0D8D87770720E405 200 1593504360 1593504061 -1 text/plain 544275/544275 GET http://xxx.xxx.xxx.xxx/blah/FEED.json<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="font-size:9.0pt;font-family:"Lucida Console";color:black">1593504361.556 SWAPOUT 00 000098D1 1865A3A26D411E7C0D8D87770720E405 200 1593504360 1593504061 -1 text/plain 544275/544275 GET http://xxx.xxx.xxx.xxx/blah/FEED.json<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="font-size:9.0pt;font-family:"Lucida Console";color:red">1593504361.607 RELEASE 00 000098D1 1865A3A26D411E7C0D8D87770720E405 ? ? ? ? ?/? ?/? ? ?<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black"><o:p> </o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black">The cached object was gradually appearing in cache_dir, until the “RELEASE” line showed up in the store.log.<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black">At this right moment, all copies of the object stored on disk were deleted.<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black"><o:p> </o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black">So I’m assuming that only one object on disk (the last one retrieved) is the object referenced as “active” by squid, all the rest being trashable.<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black">Since the client is forcing a “no-cache” header, squid does what the client is asking for, and every time it stores the object on disk.<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black">I’m also assuming that IF another client asked the same object without the “no-cache” header, squid would serve the latest cached object on disk.<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black">If I’m right so far, squid never “overwrites” the old copy of an object on disk. Instead, it stores a new one, marking it as “active”, and let the deletion task to (a)ufs threads.<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black"><o:p> </o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black">Could this this way?<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black"><o:p> </o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black">Thanks!<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black">ST<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-US" style="color:black"><o:p> </o:p></span></p>
</div>
____________________________________________________________________________________ La presente comunicazione ed i suoi allegati e' destinata esclusivamente ai destinatari. Qualsiasi suo utilizzo, comunicazione o diffusione non autorizzata e' proibita. Se
ha ricevuto questa comunicazione per errore, la preghiamo di darne immediata comunicazione al mittente e di cancellare tutte le informazioni erroneamente acquisite. Grazie This message and its attachments are intended only for use by the addressees. Any use,
re-transmission or dissemination not authorized of it is prohibited. If you received this e-mail in error, please inform the sender immediately and delete all the material. Thank you.
</body>
</html>