Starting point

As you should know Squid uses a StoreEntry structure for each and every object it has in the cache, but there is also a number of other related structures

StoreEntry

The main structure for the objects

MD5 hash

The MD5 hash is kept separately

Removal info

The removal policy also has a structure for each and every object

MemObject (not a problem)

For active or hot cached objects there is also a MemObject structure describing the in-memory object.

There are a couple of problems with this

1. For each structure there are memory allocation overhead. Usually in the range of 16 bytes.
2. Some of the structures (most notably StoreEntry) contains information that are:
   • not strictly needed to have full speed access to
   • oversized and can be shrunk down to a smaller data type
   • redundant and can be collapsed into fewer fields

Structures

NOT DONE YET. HERE THE CURRENT STRUCTURE LAYOUTS AND THEIR EXACT RELATIONSHIPS WILL BE PRESENTED