QVD read and write at the same time and consequences

[chiru_thota]

Hi All,

We have very big QVD of 2 GB size and one QVW(task) is reading data from that file.At the same time if another QVW file trys to write into that same QVD what will happen ?

Any ideas ?

Thanks,

Chiru

[ian_wilson · Accepted solution]

Scenario 1:  Read/Read - Task 1 (Read) opens the QVD file then Task 2 (Read) opens the file while Task 1 still has it open.  All tasks run fine.

Scenario 2:  Write/Read - Task 1 (Write) opens the QVD file then Task 2 (Read) also opens the file while Task 1 still has it open.  Task 2 will fail since Task 1 has the file opened exclusively and Task 1 will run fine.

Scenario 3:  Read/Write - Task 1 (Read) opens the QVD file then Task 2 (Write) also opens the file while Task 1 still has it open.  Task 2 will fail since it will not be allowed to open the file exclusively while there are other tasks reading from it.  Task 1 completes fine, Task 2 results in a failure.

[chiru_thota]

Thanks Ian for clear explanation!