[exporter/elasticsearch] Use 64 bit hash to reduce metric grouping hash and _metric_names_hash collision#41240
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carsonip
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Jul 10, 2025
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[to reviewer] This leaves us with _metric_names_hash using fnv.New32a. Do we feel comfortable changing it to xxhash as well?
| hasher := xxhash.New() | ||
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| timestampBuf := make([]byte, 8) | ||
| binary.LittleEndian.PutUint64(timestampBuf, uint64(dp.Timestamp())) |
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[to reviewer] it is actually possible to make timestamp and starttimestamp a field in the HashKey struct to reduce a dimension of possible hash collision.
axw
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Jul 11, 2025
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metric per doc cannot come soon enough 🥹
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songy23
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Jul 11, 2025
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…sh and _metric_names_hash collision (open-telemetry#41240) <!--Ex. Fixing a bug - Describe the bug and how this fixes the issue. Ex. Adding a feature - Explain what this achieves.--> #### Description Replace 32 bit hash with 64 bit xxhash to reduce metric grouping hash collisions and `_metric_names_hash` collisions. The former has a higher risk of data loss. <!-- Issue number (e.g. open-telemetry#1234) or full URL to issue, if applicable. --> #### Link to tracking issue Fixes open-telemetry#41208 <!--Describe what testing was performed and which tests were added.--> #### Testing <!--Describe the documentation added.--> #### Documentation <!--Please delete paragraphs that you did not use before submitting.-->
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Description
Replace 32 bit hash with 64 bit xxhash to reduce metric grouping hash collisions and
_metric_names_hashcollisions. The former has a higher risk of data loss.Link to tracking issue
Fixes #41208
Testing
Documentation