Questions tagged [concurrency]

For questions about issues arising when multiple users or processes concurrently access or modify shared information in a database system.

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Oracle 11g hunting down the deadlock, maybe foreign key?

I am trying to understand why a deadlock occurs in my database. The trace tells me that two updates on the same table are locking. In table is the first table to be written to in an transaction, only ...
Franz Kafka's user avatar
1 vote
1 answer
148 views

Can a Database request automatically remove itself from the queue after a delay?

I'm using table locking in my Oracle database. I have a small program with a function that locks my table, does some things and unlocks it again. If many instances are run and requests are made ...
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7 votes
3 answers
12k views

Concurrent MySQL updates hang with InnoDB (on Amazon RDS)

I'm running into a problem where multiple MySQL updates being performed at the same time will lock up and takes several minutes to finish. I'm using InnoDB, so I'm confused as to why this could be ...
Alan's user avatar
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6 votes
2 answers
6k views

Concurrent Transactions vs Simultaneous Transactions

Chapter 6 of David Kroenke's Database Concepts: Database Administration Is my understanding correct that in a database, simultaneous transactions don't really happen. Instead, it is a concurrent ...
momo's user avatar
  • 61
5 votes
2 answers
3k views

Concurrently update with limit mysql

I want to know if concurrently UPDATE .... LIMIT N will not overlap with more than one client querying the db. After UPDATE ... LIMIT N the client will make a SELECT with some client_id assigned. I ...
llazzaro's user avatar
  • 153
0 votes
1 answer
870 views

How could I handle heavy load and consistency for product inventory in online retailers? [closed]

I have posted that question on Stackoverflow and they suggest me to repost my question here, as it would more likely to get help from a DB community (regarding this issue). Hope you guys don't mind. ...
user1005234's user avatar
4 votes
2 answers
235 views

Concurrency question?

I have a MySql (5.5) database with a MS Access frontend. If two users are viewing the same record at the same time how can I make each user aware of each other? For example how would I go about ...
David's user avatar
  • 539
24 votes
2 answers
15k views

Can I create index on a table in a MySQL database while in use

And if I can, any reason (performance/stability) why I shouldn't?
Nifle's user avatar
  • 1,442
33 votes
4 answers
8k views

How do you test for race conditions in a database?

I try to write database code to make sure that it's not subject to race conditions, to make sure that I've locked the correct rows or tables. But I often wonder: Is my code correct? Is it possible to ...
xenoterracide's user avatar

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