THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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Array/Skiplist查询吞吐比随序列中的点数变化趋势
结论
（1）内存占用：skiplist 的内存占用为 array 的10倍左右
（2）写延迟：array 的写性能大约为 skiplist 的20倍
（3）读延迟：由于内存拷贝及排序，内存中的点数越多，array查询的性能越差，在1000万点时，skiplist 的查询性能约为array的5倍，100点时，skiplist 的查询性能约为array的1.5倍
(1) 内存占用：跳表的内存占用为 数组的10倍左右
(2) 写延迟：跳表的写延迟大约为 数组的20倍
(3) 读延迟：由于内存拷贝及排序，内存中的点数越多，数组查询的性能越差，在1000万点时，数组的查询延迟约为跳表的5倍，100点时，数组的查询延迟约为跳表的1.5倍
(4) 读写混合负载查询吞吐：随着每序列的点数减少，跳表的查询吞吐越来越低，最终会低于数组的查询吞吐（4）读写混合负载查询吞吐：skiplist的随着每序列的点数减少，skiplist的查询性能越来越低，最终会低于Array的查询性能
关键实验代码
单线程：
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package data_structure;
import java.util.Random;
public class Main {
private static int timeseriesNum = 1;
private static int size = 10000000;
static Random random = new Random();
public static void main(String[] args) throws InterruptedException {
multiWriteAndRead();
// for memory calculate
Thread.sleep(100000000);
}
private static void multiWriteAndRead() throws InterruptedException {
MemTable[] arrayTable = new MemTable[timeseriesNum];
MemTable[] skipListTable = new MemTable[timeseriesNum];
// skip list
long curTime = System.nanoTime();
for (int i = 0; i < timeseriesNum; i++) {
skipListTable[i] = new SkipListTable(size);
write(skipListTable[i]);
}
long finishTime = System.nanoTime();
System.out.println("SkipList write time: " + (finishTime - curTime) / 1_000_000 + " ms.");
curTime = System.nanoTime();
for (int i = 0; i < timeseriesNum; i++) {
query(skipListTable[i]);
}
finishTime = System.nanoTime();
System.out.println("SkipList query time: " + (finishTime - curTime) / 1_000_000 + " ms.");
// array
curTime = System.nanoTime();
for (int i = 0; i < timeseriesNum; i++) {
arrayTable[i] = new ArrayTable(size);
write(arrayTable[i]);
}
finishTime = System.nanoTime();
System.out.println("Array write time: " + (finishTime - curTime) / 1_000_000 + " ms.");
curTime = System.nanoTime();
for (int i = 0; i < timeseriesNum; i++) {
query(arrayTable[i]);
}
finishTime = System.nanoTime();
System.out.println("Array query time: " + (finishTime - curTime) / 1_000_000 + " ms.");
System.out.println("finished");
}
private static int query(MemTable table){
return table.query();
}
public static void write(MemTable table){
for (int i = 0; i < size; i++) {
if(random.nextDouble() < 0.2){
table.add(random.nextInt(100000) - 50000);
}
else{
table.add(i);
}
}
}
}
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