sql server - UPDATE Blocking SELECT Of Unrelated Rows -


i have tablea col1 primary key. running following transaction without committing (for test purposes). 

begin transaction update tablea set col3 = 0 col2 = 'aaa'

in meanwhile, run following query , see waits on first transaction complete.

select * tablea col2 = 'bbb'

but following query returns results immediately:

select * tablea col1 = '1'

so thought second query might need read rows have exclusive locks put first transaction in order select rows col2 = 'bbb'. that's why tried index col2 table seek not necessary did not work either. second query still waits on first transaction.

what should done prevent select blocking (except use of nolock).

p.s: transaction isolation level "read committed".


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