Adaptive Server Anywhere 9 0

LANSA Technical

Adaptive Server Anywhere 9.0
ODBI=2 (READ_COMMITTED)LockTimeout=2 (X_DBMENV.DAT)

WITH_KEY IO access

 

Step

Action (User)

IO$STS

Message

1

Insert (1)

OK

IO Operation Succeeded

2

Insert (2)

VE

Record already exists

3

Delete (2)

ER

Record Locked

4

Commit (1)

 

 

5

Update (1)

OK

IO Operation Succeeded

6

Update (2)

ER

Record Locked

7

Fetch (1)

ER

Record Locked

8

Fetch (2)

ER

Record Locked

9

Commit (1)

 

 

10

Delete (1)

OK

IO Operation Succeeded

11

Insert (2)

ER

Record Locked

12

Update (2), Delete (2)

NR

Record not found

13

Commit (1)

 

 

 

 

Note that ASA is behaving as if it is seeing the uncommitted actions of the other user, even though the Transaction Isolation Level is set to READ_COMMITTED.

Last Record Read IO access

This is a different set of steps as there must be a record to read before the last record read can be updated or deleted! Hence when an error occurs, the record must be fetched again like in Step 13.

Step

Action (User)

IO$STS

Message

1

Insert (1)

OK

IO Operation Succeeded

2

Insert (2)

VE

Record already exists

3

Commit (1)

 

 

4

Fetch (1), Fetch (2)

OK

IO Operation Succeeded

5

Update (1)

OK

IO Operation Succeeded

6

Update (2)

ER

Record Locked

7

Fetch (1)

ER

Record Locked

8

Fetch (2)

ER

Record Locked

9

Commit (1)

 

 

10

Fetch (1), Fetch (2)

OK

IO Operation Succeeded

11

Delete (1)

OK

IO Operation Succeeded

12

Insert (2)

ER

Record Locked

13

Fetch (2) Update (2), Fetch (2) Delete (2)

NR

Record not found

14

Commit (1)

 

 

 

 

Note in Step 13 that the Update and Delete cannot proceed because the record is not found.