mirror of https://gitee.com/bigwinds/arangodb
50 lines
1.9 KiB
Markdown
50 lines
1.9 KiB
Markdown
---
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layout: default
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description: TTL (time-to-live) Options
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---
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# TTL (time-to-live) Options
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## TTL background thread frequency
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`--ttl.frequency`
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The frequency for invoking the TTL background removal thread. The value for this
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option is specified in milliseconds.
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The lower this value, the more frequently the TTL background thread will kick in
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and scan all available TTL indexes for expired documents, and the earlier the
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expired documents will actually be removed.
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## TTL maximum total removals
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`--ttl.max-total-removes`
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In order to avoid "random" load spikes by the background thread suddenly kicking
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in and removing a lot of documents at once, the number of to-be-removed documents
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per thread invocation can be capped.
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The TTL background thread will go back to sleep once it has removed the configured
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number of documents in one iteration. If more candidate documents are left for
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removal, they will be removed in following runs of the background thread.
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## TTL maximum per-collection removals
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`--ttl.max-collection-removes`
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This option controls the maximum number of documents to be removed per collection
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in each background thread run. This value can be configured separately from the
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total removal amount so that the per-collection time window for locking and potential
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write-write conflicts can be reduced.
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## TTL only for loaded collections
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`--ttl.only-loaded-collection`
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This option will only scan TTL indexes of collections that are already loaded into
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memory. Setting the option to false will make the background thread ignore collections
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that are currently not loaded. This saves the background thread from loading all
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collections into memory.
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This option is useful for the MMFiles engine only, where collections need to be
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loaded into memory first. For the RocksDB engine, collections do not need to be loaded
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into memory first, so this option does not make any difference.
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