Description
resource 
sqlite_popen ( string filename [, int mode [, string &error_message]] )
   This function behaves identically to sqlite_open()
   except that is uses the persistent resource mechanism of PHP.
   For information about the meaning of the parameters, read the
   sqlite_open() manual page.
  
   sqlite_popen() will first check to see if a persistent
   handle has already been opened for the given
   filename.  If it finds one, it returns that handle
   to your script, otherwise it opens a fresh handle to the database.
  
   The benefit of this approach is that you don't incur the performance
   cost of re-reading the database and index schema on each page hit served
   by persistent web server SAPI's (any SAPI except for regular CGI or CLI).
  
Note: 
    If you use persistent handles and have the database updated by a
    background process (perhaps via a crontab), and that process re-creates
    the database by overwriting it (either by unlinking and rebuilding, or
    moving the updated version to replace the current version),
    you may experience undefined behaviour when a persistent handle on the
    old version of the database is recycled.
   
    To avoid this situation, have your background processes open the same
    database file and perform their updates in a transaction.