Tag: ACID
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CAP Twelve Years Later: How the “Rules” Have Changed
Eric Brewer about CAP Twelve Years Later: How the “Rules” Have Changed: The CAP theorem asserts that any networked shared-data system can have only two of three desirable properties. However, by explicitly handling partitions, designers can optimize consistency and availability, thereby achieving some trade-off of all three. In the decade since its introduction, designers and…
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The Consistency Alphabet Soup
The Consistency Alphabet Soup: It seems that newcomers to distributed systems are often confused by the various definitions of the C-word. I want to go over them to draw a distinction that is often overlooked, without getting into the tired old arguments around eventual consistency. Specifically, I want to expand on the distinction between properties…
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When is “ACID” ACID? Rarely!
When is “ACID” ACID? Rarely. ACID and NewSQL databases rarely provide true ACID guarantees by default, if they are supported at all Not even Oracle or DB2 provide full ACID (in distributed scenarios at least).
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Google’s Megastore
I don’t think I’ve written about Google’s Megastore yet, so here’s a quick summary of worthwile resources. Megastore is the data engine supporting the Google Application Engine. It’s a scalable structured data store providing full ACID semantics within partitions but lower consistency guarantees across partitions. James Hamilton’s take on Google Megastore: The Data Engine Behind…
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When do you need ACID?
The recent JPMorgan Chase outage caused by an Oracle RAC block corruption places an old question back on the agenda that gets ignored way too often: How to tell whether you need ACID-compliant transaction integrity. The cost of ACID in large database systems is so high that you should consider moving those parts to simpler,…
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