GSAK enables you to accumulate as many logs as you like in the database. However, over time the number of logs can get quite large and slow down performance. You now have the ability to purge out logs from your databases. You can purge by number of logs (For example, any logs greater than 20 for a cache ) or log date (For example, all logs older than a certain date)
By number of logs - If the log count for any cache is greater than the corresponding number you enter, then all logs greater than that number will be deleted. That is, the 20 most current logs will be kept.
By date - if the log date is older than the date you enter then the corresponding log will be deleted.
By age - if the log is older than the specified number of days/weeks/months/years.
By user Id - Multiple user Id's can be entered by separating each with a ; (semi colon). Each matching log is then deleted.
Always keep logs by me - If you check this box (recommended) then regardless of your purge settings, all logs by you will be kept. (this includes found, not found, notes, etc)
Preserve Last 4 logs and last found date - Check this option to make sure you keep logs that effect the integrity of the last four logs and last found date (more information)
Keep logs with Id in list - Multiple user Id's can be entered by separating each with a ; (semi colon). Each matching log is kept, regardless if it matched your purge criteria above.
Always keep publish log - Never purge the publish log regardless of purge options selected.
To find a user id please see this link