ACID (Atomicity, Consistency, Isolation, Durability) is a set of properties that guarantee that database transactions are processed reliably.

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Transaction atomicity implies consistency

Transactions are said to need both atomicity and consistency. But, what is the point of consistency? Once you ensure that you either update both accounts on money transfer, you are consistent. ...
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innodb_flush_log_at_trx_commit=1 and flush-to-disk reality

I use the default settings of MySQL 5.5 on various servers and I have the following table: create table test._perf ( name varchar(255) not null ) engine=InnoDB; I have an .sql script which ...
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Consistency in ACID and CAP theorem, are they the same?

From my understanding, the consistency in ACID is ensuring the data integrity. However, the consistency in CAP means the data can appear quickly in distributed system. Does that mean: they are not ...
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Half of a transaction completes, when the other half fails?

I have done some searching on SO, MSDN, and various other sources, and I found plenty of questions about transactions, but none that seem to be exactly what I'm dealing with. Admittedly I'm still ...
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Scalability question

There is a DB {MySql} with 5 tables A, BIG, C, D, E. Their grow factor is about 1/100/1/1/1. The table BIG has Insert/Read/Update request ratio about 1/10/2. The Inserts and Updates 'cannot fail'. ...
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ACID violation in Postgres 9.1?

I am using a postgres DB to implement a scheduling of jobs for a large number of computers/processes. To make the story short, every job has its id, all scheduling is implemented with three tabes: all ...
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Is it possible that records are changed while a read query is still executing?

Suppose a read (select) query R is reading some 100 records from a table, 50 records are read so far, could in the meanwhile a write query W change some of the unread records? We didn't take any ...
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How to configure read transactions to never cause other write serialization transactions to fail

I am protecting critical transactions with application mutexes and SERIALIZABLE. I presume that this makes these operations as acid as possible, but now I'm concerned that reads might cause failures ...
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Reference implementation of a scalable storage system with strong consistency?

Is there a storage system with these properties? horizontally scalable - can handle arbitrary read and write throughput if you add enough nodes to the cluster consistent, in the sense that all reads ...
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Synchronization using triggers

I have a requirement similar to previous discussions at: Writing a simple bank schema: How should I keep my balances in sync with their transaction history? Trigger in combination with transaction ...
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Can You Drop Consistency from ACID?

In his book "An Introduction to Database Systems" C.J.Date wrote a chapter about the ACID principles called "Dropping ACID". In this chapter he calls Correctness(Consistency) "essentially meaningless" ...
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row locking within ACID transaction innodb

I have a financial transaction that looks something like this (pseudo): begin select record for update update record(same record as selected) insert another record into another table ...
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Transaction level difference between using a large IN filter VS. “BEGIN TRAN/COMMIT”

I would like to delete about 100,000 records with minimal server overhead. I've had a few nagging questions I haven't been able to test properly so I figured I'd ask some experts here. Which would ...