'Read committed' diaporamas de présentation

Understanding Firebird Transactions

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Concurrency and Transaction Processing

Concurrency and Transaction Processing. Concurrency models. 1. Pessimistic avoids conflicts by acquiring locks on data that is being read, so no other processes can modify that data

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Quantifying Isolation Anomalies

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Lecture 11: Transactions in SQL

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Performance Tuning

Performance Tuning. Next, we focus on lock-based concurrency control, and look at optimising lock contention. The key is to combine the theory of concurrency control with practical DBMS knowledge Goal: maximise DBMS throughput (not the response time of any single transaction). Lock Tuning (I).

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Lecture 13: Transactions in SQL

Lecture 13: Transactions in SQL. Wednesday, October 26, 2005. Overview. Chapter 8.6 Note: this is an easy introduction to transactions; more details when we discuss implementations. Multiple users: single statements. Client 1:

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Lecture 13: Transactions in SQL

Lecture 13: Transactions in SQL. Wednesday, October 26, 2005. Overview. Chapter 8.6 Note: this is an easy introduction to transactions; more details when we discuss implementations. Multiple users: single statements. Client 1:

310 views • 23 slides

CS422 Principles of Database Systems Introduction to Transactions

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CSI3130

CSI3130. Transactions in PostgreSQL Fatemeh Nargesian SITE, uOttawa. What is a transaction?. A transaction is a group of SQL commands whose results will be made visible to the rest of the system as a unit when the transaction commits or not at all, if the transaction aborts .

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Isolation Levels

Isolation Levels. Phantoms a phantom with respect to transaction T1 is a new record that comes into existence, created by a concurrent transaction T2, that satisfies a search condition used by T1 consider transactions that include the following operations:. T1 SELECT * FROM a

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What is Undo and Redo in DBA?

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