[SERVER-77698] Replace MurmurHash3 with absl::Hash if possible in SimpleStringDataComparator::hash_combine Created: 01/Jun/23 Updated: 31/Oct/23 |
|
| Status: | Blocked |
| Project: | Core Server |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Task | Priority: | Major - P3 |
| Reporter: | Dan Larkin-York | Assignee: | Backlog - Query Execution |
| Resolution: | Unresolved | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
|
||||||||||||||||||||
| Assigned Teams: |
Query Execution
|
||||||||||||||||||||
| Sprint: | QE 2023-06-26, QE 2023-07-10, QE 2023-07-24, QE 2023-08-07, QE 2023-08-21, QE 2023-09-04, QE 2023-09-18, QE 2023-10-02 | ||||||||||||||||||||
| Participants: | |||||||||||||||||||||
| Description |
|
MurmurHash3 is a pretty old hash function that's slow and produces low-quality hashes compared to modern alternatives like absl::Hash (CityHash). We want to replace any uses of MurmurHash3 which are for in-memory use only, as we expect this to yield quick perf wins. Hash values that are persisted to disk across restarts or sent across the network between servers are likely unsafe to change, and should be annotated with a clear explanation for why the usage requires a stable hash computation. |
| Comments |
| Comment by Ivan Fefer [ 31/Oct/23 ] |
|
Postponing this ticket until we resolveĀ SERVER-82618 that will affect what hash are we going to use |
| Comment by David Storch [ 09/Oct/23 ] |
|
It seems like this ticket is in a bad state, since it's scheduled but unassigned. I'll put it back into the QE triage queue. |
| Comment by Dan Larkin-York [ 06/Jun/23 ] |
|
Sending over to QE to take a look. |