Score[0]=1000
Start
Calculate the time of current compaction，and add it to the time used
Whether the layer has occupied the time slice
The time slice has been used longer than the time slice threshold.
N
Y
Wait for compaction triggering
The number of files is not less than N1
The number of files reached N3
Count the number of files in L1-L6 layer respectively
Count the number of files in L0 layer
The compaction will select the layer of the highest score
L0 layer does not participate in current compaction
Calculate the score of each layer based on the formula: score [i] = The number of files in Li layer/The threshold of Li layer
The number of files in L0 layer is larger than the threshold
Reset time slice，and this layer occupies time slice
The number of files is not less than N2
