Though have so many handy hints on PHP, MySql, this is quick and easy one....

On every page to display the page you look at, it uses a long sequence of various characters that sort of make a lot of reading for anyone....
now consider for a second if you have 1 number and then use the alphabet with this how many sequences even that can make.

why would you want 32 being indexed twice?? MySql is an indexing system to begin with so data is also a form of indexing and any extra key indexes are only a quicker solution to search over a table.

So if you half the number needed you are also Halfling the amount of data required.

this can be done by adding a number to the amount of digits used in a MySql index key.

so for our 32 characters long session id primary that was indexed fully with 32 characters, that is now halved and reduces the time taken to fetch each page.


The instructions to delete the data are for data and not indexes so will see how it affect deletion of old ones, yet should be the same as the information is being removed from the Data.