mvcc: Limit number of bbolt read transactions opened by committed reads #3
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jingyih
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Feb 13, 2019
mvcc/backend/backend.go
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| // we can use its data to enforce our limit. | ||
| concurrentReadTxns := b.db.Stats().OpenTxN | ||
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| for i := 0; i < (maxConcurrentReadTxns - concurrentReadTxns); i++ { |
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We probably need to run some simple benchmarks to find out what is the typical value for concurrentReadTxns.
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It's 1 + number of committed reads. Double checked it with a benchmark. Adding a gauge metric to this PR for the concurrentReadTxns value.
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But we will need to determine what a reasonable limit might be. I'm not 100% convinced that # of concurrent requests is sufficient, got an idea for another approach where we weight requests by their response count.
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Merging this for image build. Post-commit reviews still welcome. |
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