Dirty reads

Dirty reads

Post by Shami Palanive » Thu, 01 Aug 1996 04:00:00

Is there anything like NO LOCK option in sybase SQL server10.0.3.

The SELECT stmt (even without holdlock, isolation level=1,
unchained tran mode) momentarily acquires shared lock on the page
that is being read/selected (Sh_page).  This sometime conflicts
with a long (4 mins, not too long I guess) running transaction
(updates) and causes deadlock.  Is there any way where we can force
a SELECT stmt to retrieve records without any lock.  It is ok even
if the data is dirty.

Following is the scenario of the tran execution:

User 1                      User 2
------                      ------
Begin tran          
Update ... (locks pg 1)
                            Select ... (waiting to lock pg 1)

What I really want is the "select..." by User 2
should not acquire any locks.

I appreciate any help in this re:


Shami Palanivelu           ;

University of NorthDakota  ;     701-777-2151 (Phone)
Grandforks, ND - 58202     ;     701-777-2940 (Fax)


Dirty reads

Post by Karen Hogobo » Sat, 03 Aug 1996 04:00:00

>Is there anything like NO LOCK option in sybase SQL server10.0.3.

No...this functionality wasn't added until 10.1.  In releases before
that, you'll need some sort of work around...I vagely remember a
hack where you could avoid the deadlock by forcing an early ex lock
instead of the intent lock using something like delete ... where 1 = 0.  
The other option is to periodically create a temp table for the reader,
but this of course depends entirely on how often the data changes and
how current it needs to be for the reader.



My opinions are only my own.


Dirty reads

Post by RGCramot » Thu, 08 Aug 1996 04:00:00

Quote:Fairclough) writes:
>when trying to dump using system 11 on solaris 2.5 with the following

>dump database megabase to '/dev/nrtape' with init

>i get

>Backup Server: OPERATOR: Volume on device '/dev/nrtape' cannot
>opened for write access.  Mount another volume.

I know this sounds basic, but, is the tape write protected?

Richard Cramotte, Jr.
Sybase DBA