why commit while finish a select statment

[heming_g]

i saw some code typing 'EXEC SQL COMMIT' after a cursor fetch .
isn't it just a share lock while fetching ?

[Matt Emmerton]

<he******@hotmail.com> wrote in message
news:11**********************@z14g2000cwz.googlegr oups.com...

i saw some code typing 'EXEC SQL COMMIT' after a cursor fetch .
isn't it just a share lock while fetching ?

Yes, provided the cursor was not defined with FOR UPDATE.

However, locks (both shared and update) are held until a COMMIT is issued.
So you must COMMIT after issuing read-only queries so that these share locks
will be released.

--
Matt Emmerton

[heming_g]

you mean COMMIT just releases system resource but has no effect on
enhance concurrency ?

[Knut Stolze]

he******@hotmail.com wrote:

you mean COMMIT just releases system resource but has no effect on
enhance concurrency ?

It does have an effect on concurrency if other transactions (units of work)
update the table where the query was run and, therefore, could be blocked
by the shared locks.

--
Knut Stolze
DB2 Information Integration Development
IBM Germany