There is not really a limit on that. Underneath, the client will deal with following regions around if the move, a new master if there is a failover, etc...
The only thing that cannot be left open indefinitely is a scanner (they have a server-side lease and expire if left idle).
> -----Original Message-----
> From: Peter Haidinyak [mailto:[EMAIL PROTECTED]]
> Sent: Monday, February 07, 2011 10:07 AM
> To: [EMAIL PROTECTED]
> Subject: How long can I have a table open?
> During my import process I create a connection to a table. How long can I
> leave that connection open without using it before HBase will try to close it?
> Hadoop 0.20.2+737
> HBase 0.89.20100924+28