mirror of https://gitee.com/bigwinds/arangodb
44 lines
1.5 KiB
Plaintext
44 lines
1.5 KiB
Plaintext
!CHAPTER Administrating ArangoDB
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!SUBSECTION Mostly Memory/Durability
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Database documents are stored in memory-mapped files. Per default, these
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memory-mapped files are synced regularly but not instantly. This is often a good
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tradeoff between storage performance and durability. If this level of durability
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is too low for an application, the server can also sync all modifications to
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disk instantly. This will give full durability but will come with a performance
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penalty as each data modification will trigger a sync I/O operation.
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!SECTION AppendOnly/MVCC
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Instead of overwriting existing documents, a completely new version of the
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document is generated. The two benefits are:
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* Objects can be stored coherently and compactly in the main memory.
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* Objects are preserved-isolated writing and reading transactions allow
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accessing these objects for parallel operations.
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The system collects obsolete versions as garbage, recognizing them as
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forsaken. Garbage collection is asynchronous and runs parallel to other
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processes.
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!SECTION Configuration
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!SUBSECTION Global Configuration
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There are certain default values, which you can store in the configuration file
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or supply on the command line.
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!SUBSECTION Maximal Journal Size
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<!-- arangod/RestServer/ArangoServer.h -->
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@startDocuBlock databaseMaximalJournalSize
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!SECTION Per Collection Configuration
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You can configure the durability behavior on a per collection basis.
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Use the ArangoDB shell to change these properties.
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!SUBSECTION Properties
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<!-- arangod/V8Server/v8-vocbase.cpp -->
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@startDocuBlock collectionProperties
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