database - RocksDB JNI 慢读性能

Question

我正在使用 RocksDB JNI，我发现该程序的读取速度呈指数级增长

最初，它在可接受的范围内。但是当程序运行以使总记录达到 100 万条时，读取时间记录器打印显示大约 200-300 毫秒。随着程序的运行，情况变得更糟。我是否使用错误的 JNI？

long n = 0;
int counter = 0;
try(
final Options options = new Options()
.setCreateIfMissing(true)
.setComparator(new Comparator(new ComparatorOptions()){

                @Override
                public String name() {
                    return "default";
                }

                @Override
                public int compare(final Slice a, final Slice b) {
                    long x = ByteBuffer.wrap(a.data()).getLong();
                        long y = ByteBuffer.wrap(b.data()).getLong();
                        return (x < y) ? -1 : ((x == y) ? 0 : 1);
                }
            })
                    .setWriteBufferSize(64 * SizeUnit.MB)
                    .setMaxWriteBufferNumber(6)
                    .setMinWriteBufferNumberToMerge(2);
            final RocksDB db = RocksDB.open(options, "/PathToDB/")){
        boolean loop = true;
        while(loop) {
            if(n == Long.MAX_VALUE){
                loop = false;
            }
            for (int j=0;j<4;j++){
                try(WriteBatch writeBatch = new WriteBatch()) {
                    for (int i = 0; i < 200; i++) {
                        String urlStr = "dummy"+counter;
                        counter++;
                        Long score = getScore(urlStr);
                        ByteBuffer buf = ByteBuffer.allocate(Long.BYTES);
                        buf.putLong(score);
                        writeBatch.put( buf.array() , urlStr.getBytes(UTF_8));
                    }
                    long st = System.currentTimeMillis();
                    db.write(new WriteOptions(), writeBatch);
                    long et = System.currentTimeMillis();
                    logger.logMessage(Test.class.getName(), Level.INFO, "RocksDB write of 200 URLs successful. Time taken - {0}", new Object[]{ et-st});
                } catch (RocksDBException ex) {

                }
            }
            byte[] firstKey = null, lastKey = null;
            int readC = 0;
            long st = System.currentTimeMillis();
            final RocksIterator it = db.newIterator();
            it.seekToFirst();
            while(it.isValid() && readC < 50){
                lastKey = it.key();
                if(firstKey == null){
                    firstKey = lastKey;
                }
                it.next();
                readC++;
            }
            long et = System.currentTimeMillis();
            logger.logMessage(Test.class.getName(), Level.INFO, "RocksDB read of 50 URLs successful. Time taken - {0}", new Object[]{ et-st});
            if(lastKey != null){
                db.deleteRange(firstKey, lastKey);
            }
            n++;
        }
    }catch (Exception e){
        logger.logMessage(Level.SEVERE, Test.class.getName(), e);
    }

标签： databaseperformancerocksdb-java