Questions tagged [database-concurrency]
The database-concurrency tag has no usage guidance.
6
questions
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70 views
Does timestamp protocol following thomas's write rule allow non-view-serializable schedules in some cases?
I have came across following line in text book (Database System Concepts
Textbook by Avi Silberschatz, Henry F. Korth, and S. Sudarshan $6e$) page no. 686:
Thomas’ write rule allows schedules that ...
0
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0answers
11 views
Does graph based protocol in DBMS suffer from starvation issues?
I know that graph based protocols require prior knowledge of access of data items. Besides when a transaction locks some data item in graph based protocol it also locks some unnecessary data items ...
1
vote
1answer
20 views
Does basic 2 PL always ensure conflict serializability?
While going through the DBMS book by Korth, it was mentioned :
" For a set of transactions, there may be conflict-serializable schedules that
cannot be obtained through the two-phase locking ...
2
votes
1answer
217 views
Why do OS and DBMS have their own synchronisation mechanisms, when OS can alone do it and it sits at the bottom of DB?
I know that synchronization is important in the OS, but why do we need a separate topic synchronization and concurrency in the DBMS? The OS concentrates on program synchronization while the DBMS ...
0
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0answers
26 views
Understanding non repeatable read anomaly in databases
This paper discusses in detail ANSI isolation levels discussed in ANSI SQL standard on page 84.
Paper introduces following shorthand for describing histories which contain reads, writes, commits and ...
0
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91 views
Understanding repeatable read isolation level
Wikipedia defines following terms:
With a lock-based concurrency control DBMS implementation, serializability isolation level requires read and write locks (acquired on selected data) to be ...
