phpsessionmanual,PHP:session_gcManual

说明

session_gc

(

) : int|false

session_gc() is used to perform session data

GC(garbage collection). PHP does probability based session GC by

default.

Probability based GC works somewhat but it has few problems. 1) Low

traffic sites&＃39; session data may not be deleted within the preferred

duration. 2) High traffic sites&＃39; GC may be too frequent GC. 3) GC is

performed on the user&＃39;s request and the user will experience a GC

delay.

Therefore, it is recommended to execute GC periodically for

production systems using, e.g., "cron" for UNIX-like systems.

Make sure to disable probability based GC by setting

session.gc_probability

to 0.