oom caused after use #234's statistics record code

[itherunder]

#234

[tatsuya6502]

Hi. Thank you for reporting the issue. Can you please provide more information to help us investigate further?

• What is the moka version?
• What is the cache implementation? sync::Cache, sync::SegmentedCache, or future::Cache?
• Is your eviction listener code exactly same to the one in Statistics for metrics #234?
• What is the max_capacity of the cache?
• If you make the max_capacity smaller, does the issue still happen?
• What is the average size of the value stored in the cache? (Rough estimate is fine)
• What is the write rate to the cache? (Number of writes per second. Rough number is fine)
  • Are you doing heavy writes? (e.g. millions writes per second, like benchmarking)

[itherunder]

Hi. Thank you for reporting the issue. Can you please provide more information to help us investigate further?

• What is the moka version?

• What is the cache implementation? sync::Cache, sync::SegmentedCache, or future::Cache?

• Is your eviction listener code exactly same to the one in Statistics for metrics #234?

• What is the max_capacity of the cache?

• If you make the max_capacity smaller, does the issue still happen?

• What is the average size of the value stored in the cache? (Rough estimate is fine)

• What is the write rate to the cache? (Number of writes per second. Rough number is fine)

  • Are you doing heavy writes? (e.g. millions writes per second, like benchmarking)

• 0.11.2
• sync::SegmentedCache / I tried sync::Cache, same oom
• exactly same as Statistics for metrics #234
• still happen, I tried to set max_capacity just 128
• 20B
• 1000 QPS

[tatsuya6502]

@itherunder — Thank you for the info. It was very helpful! I believe I found the root cause of the bug, and the following PR will fix it:

• Fix a bug in sync caches where memory usage kept increasing when the eviction listener is set (v0.11.x) #295
  • src/sync_base/key_lock.rs#L33-R33

When you have chance, please try it to see if the OOM is fixed:

Cargo.toml

(deleted)

I will apply the fix to Moka v0.11.x, v0.10.x and v0.9.x, and hopefully we can release them in this weekend.

---

EDIT

I just published v0.11.3 to crates.io.

Cargo.toml

[dependencies]
moka = "v0.11.3"

[tatsuya6502]

I will apply the fix to Moka v0.11.x, v0.10.x and v0.9.x, and hopefully we can release them in this weekend.

I just published v0.11.3, v0.10.4 and v0.9.9 to crates.io.

Please reopen this issue if the OOM still happens with v0.11.3.