Sybase read row with WriteNoPK using iSQL

Question

i'm using Sybase SQL Anywhere 12. Let me say I have a Table user with the following connections to it:

conn_name   conn_id user_id table_type  creator table_name  index_id    lock_class  lock_duration   lock_type   row_identifier
SQL_DBC_a2a1060 3193    DBA BASE        DBA     user        (NULL)      Row         Transaction     WriteNoPK   37431476262
SQL_DBC_a2a1060 3193    DBA BASE        DBA     user        (NULL)      Row         Transaction     Intent      45309427737
SQL_DBC_a2a1060 3193    DBA BASE        DBA     user        (NULL)      Row         Transaction     WriteNoPK   45309427737
SQL_DBC_a2a1060 3193    DBA BASE        DBA     user        (NULL)      Row         Transaction     Intent      37399035938
SQL_DBC_a2a1060 3193    DBA BASE        DBA     user        (NULL)      Row         Transaction     WriteNoPK   37399035938
SQL_DBC_a2a1060 3193    DBA BASE        DBA     user        (NULL)      Row         Transaction     Intent      37399035939

If I'm now going to SELECT * FROM user from within Sybase SQL Anywhere I'll get all rows and data as expected.

But if i'm going to fire the same SQL-Statement using the DBA-User in iSQL on OpenSuse 11.4, the Statement runs and I receive results till the row which is going to be selected has the WriteNoPK-Lockflag set. The Statement than states the follwoing error:

Server message number=8405 severity=21 state=0 line=0 text=SQL Anywhere Error -210: User 'XYZ' has the row in 'user' locked , SQL: 'SELECT * FROM user'

Is there a possibility to read/select even if the row is WriteNoPK-Locked?

Many thanks, Max

Answer 1

This is a result of the isolation level of your connection. The row is update locked, which prevents other processes from getting a possible 'dirty read' (e.g. reading an updated value that has not been committed, and could be rolled back)

To view your current isolation level:

SELECT CONNECTION_PROPERTY('isolation_level');

This section in the SQLAnywhere docs talks about the different isolation level settings, and how to change them. Isolation level 0, or 1 would probably allow your read to continue, but with some risk. You may also want to check out the snapshot isolation setting to see if it might suit your needs.

http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.help.sqlanywhere.12.0.1/dbusage/udtisol.html