Avoid unnecessary work

When optimizing performance-critical code paths, eliminate redundant operations and unnecessary processing:

1. Exit loops early when a decision has been made and no further iterations are needed:

   // Good: Break out of the loop once we find what we need
   for _, f := range files {
    if tsmPointsPerBlock := fileStore.BlockCount(f, 1); tsmPointsPerBlock == aggressivePointsPerBlock {
        pointsPerBlock = aggressivePointsPerBlock
        break // No need to check remaining files
    }
   }
   

2. Cache calculated values that are used multiple times, especially expensive calculations: ```go // Good: Calculate time bounds once and reuse futureTimeLimit := time.Now().Add(rp.FutureWriteLimit) pastTimeLimit := time.Now().Add(-rp.PastWriteLimit)

// Check points against cached limits for _, p := range points { if p.Time().After(futureTimeLimit) || p.Time().Before(pastTimeLimit) { // Point outside time window } }

3. **Skip reprocessing** data that already meets target criteria:
```go
// Good: Use >= instead of == to avoid recompacting already optimized files
if blockCount >= targetBlockCount && !hasTombstones {
    // Skip this file, it's already optimized
}

1. Use direct operations rather than unnecessary function calls for deterministic results:

   // Good: Use copy directly instead of looping with a function that always returns true
   shards := make([]*Shard, 0, len(s.shards))
   copy(shards, s.shards)
   

These optimizations reduce CPU cycles, memory allocations, and I/O operations, leading to more efficient code execution, particularly in performance-sensitive areas.