Tagged Questions
1
vote
0answers
33 views
Does SQL Server place shared locks on scanned records when using REPEATABLE READ [duplicate]
Assume a SQLCmd session which is using transaction isolation level REPEATABLE READ.
In this session I start a transaction and execute an UPDATE statement with a WHERE clause on a non indexed column. ...
0
votes
0answers
48 views
What would this non-'unique index with a unique search condition` query lock?
I am not sure about this part of the transaction manual
For locking reads (SELECT with FOR UPDATE or LOCK IN SHARE MODE), UPDATE, and DELETE statements, locking depends on whether the statement ...
5
votes
4answers
530 views
MySQL InnoDB locks primary key on delete even in READ COMMITTED
Preface
Our application runs several threads that execute DELETE queries in parallel. The queries affect isolated data, i.e. there should be no possibility that concurrent DELETE occurs on the same ...
3
votes
1answer
310 views
How to force the use of row locks?
I am trying to get my table to use row locks. I have already disabled lock escalation. The isolation level is READ_COMMITTED_SNAPSHOT
alter table <TABLE_NAME> SET (LOCK_ESCALATION=DISABLE)
go
...
4
votes
2answers
161 views
Schema blocking in READ_COMMITTED_SNAPSHOT
I am trying to troubleshoot locking behavior and the READ_COMMITTED_SNAPSHOT isolation level while attempting to resolve concurrency issues.
Background: Assume an online ordering system (ecommerce). ...
13
votes
3answers
1k views
Managing concurrency when using SELECT-UPDATE pattern
Let's say you have the following code (please ignore that it's awful):
BEGIN TRAN;
DECLARE @id int
SELECT @id = id + 1 FROM TableA;
UPDATE TableA SET id = @id; --TableA must have only one row, ...
5
votes
3answers
1k views
SQL Server - what isolation level for non-blocking select statements?
I have a long running transaction (called, say, T1) that performs some deletes, updates and inserts on a table in SQL Server 2008 R2. At the same time, another process periodically runs select ...
