feat: Add Operator Cache for databend #18196
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Signed-off-by: Xuanwo <[email protected]>
Signed-off-by: Xuanwo <[email protected]>
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Jun 20, 2025
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| let cache_key = self.compute_cache_key(params); | ||
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| // Check if we have a cached operator | ||
| { | ||
| let mut cache = self.cache.lock().unwrap(); | ||
| if let Some(operator) = cache.get(&cache_key) { | ||
| debug!("Operator cache hit for key: {}", cache_key); | ||
| CACHE_HIT_COUNT.inc(); | ||
| return Ok(operator.clone()); | ||
| } | ||
| } | ||
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| // Cache miss, create new operator | ||
| debug!("Operator cache miss for key: {}", cache_key); | ||
| CACHE_MISS_COUNT.inc(); | ||
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| let operator = init_operator_uncached(params)?; | ||
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| // Insert into cache | ||
| { | ||
| let mut cache = self.cache.lock().unwrap(); | ||
| cache.put(cache_key, operator.clone()); |
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How about using StorageParams as cache key? it already implemented (in this PR) Hash and Eq, in this way we don't need to worry about collisions that could occur with the compute_cache_key: StorageParams -> u64 function.
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Makes sense, let me give it a try.
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Summary
Add Operator Cache for databend.
Databend uses OpenDAL to access object storage. When accessing through an IAM role, OpenDAL internally uses reqsign to call AWS's API and obtain a temporary token. However, this API has a ratelimit. If users are frequently creating external tables, this can often cause query failures.
This PR address this by introduce an operator cache which can resuse the same operator if inputs are the same.
Tests
Type of change
This change is