@Test
public void snapshots() throws RocksDBException {
RocksDB db = null;
Options options = null;
ReadOptions readOptions = null;
try {
options = new Options();
options.setCreateIfMissing(true);
db = RocksDB.open(options, dbFolder.getRoot().getAbsolutePath());
db.put("key".getBytes(), "value".getBytes());
// Get new Snapshot of database
Snapshot snapshot = db.getSnapshot();
readOptions = new ReadOptions();
// set snapshot in ReadOptions
readOptions.setSnapshot(snapshot);
// retrieve key value pair
assertThat(new String(db.get("key".getBytes()))).isEqualTo("value");
// retrieve key value pair created before
// the snapshot was made
assertThat(new String(db.get(readOptions, "key".getBytes()))).isEqualTo("value");
// add new key/value pair
db.put("newkey".getBytes(), "newvalue".getBytes());
// using no snapshot the latest db entries
// will be taken into account
assertThat(new String(db.get("newkey".getBytes()))).isEqualTo("newvalue");
// snapshopot was created before newkey
assertThat(db.get(readOptions, "newkey".getBytes())).isNull();
// Retrieve snapshot from read options
Snapshot sameSnapshot = readOptions.snapshot();
readOptions.setSnapshot(sameSnapshot);
// results must be the same with new Snapshot
// instance using the same native pointer
assertThat(new String(db.get(readOptions, "key".getBytes()))).isEqualTo("value");
// update key value pair to newvalue
db.put("key".getBytes(), "newvalue".getBytes());
// read with previously created snapshot will
// read previous version of key value pair
assertThat(new String(db.get(readOptions, "key".getBytes()))).isEqualTo("value");
// read for newkey using the snapshot must be
// null
assertThat(db.get(readOptions, "newkey".getBytes())).isNull();
// setting null to snapshot in ReadOptions leads
// to no Snapshot being used.
readOptions.setSnapshot(null);
assertThat(new String(db.get(readOptions, "newkey".getBytes()))).isEqualTo("newvalue");
// release Snapshot
db.releaseSnapshot(snapshot);
} finally {
if (db != null) {
db.close();
}
if (options != null) {
options.dispose();
}
if (readOptions != null) {
readOptions.dispose();
}
}
}
@Override
public void init() throws DBException {
System.out.println("Initializing RocksDB...");
String db_path = DB_PATH;
options = new Options();
options
.setCreateIfMissing(true)
.createStatistics()
.setWriteBufferSize(8 * SizeUnit.KB)
.setMaxWriteBufferNumber(3)
.setMaxBackgroundCompactions(10)
.setCompressionType(CompressionType.SNAPPY_COMPRESSION)
.setCompactionStyle(CompactionStyle.UNIVERSAL);
Statistics stats = options.statisticsPtr();
assert (options.createIfMissing() == true);
assert (options.writeBufferSize() == 8 * SizeUnit.KB);
assert (options.maxWriteBufferNumber() == 3);
assert (options.maxBackgroundCompactions() == 10);
assert (options.compressionType() == CompressionType.SNAPPY_COMPRESSION);
assert (options.compactionStyle() == CompactionStyle.UNIVERSAL);
assert (options.memTableFactoryName().equals("SkipListFactory"));
options.setMemTableConfig(
new HashSkipListMemTableConfig()
.setHeight(4)
.setBranchingFactor(4)
.setBucketCount(2000000));
assert (options.memTableFactoryName().equals("HashSkipListRepFactory"));
options.setMemTableConfig(new HashLinkedListMemTableConfig().setBucketCount(100000));
assert (options.memTableFactoryName().equals("HashLinkedListRepFactory"));
options.setMemTableConfig(new VectorMemTableConfig().setReservedSize(10000));
assert (options.memTableFactoryName().equals("VectorRepFactory"));
options.setMemTableConfig(new SkipListMemTableConfig());
assert (options.memTableFactoryName().equals("SkipListFactory"));
// options.setTableFormatConfig(new PlainTableConfig());
// // Plain-Table requires mmap read
// options.setAllowMmapReads(true);
// assert(options.tableFactoryName().equals("PlainTable"));
//
// options.setRateLimiterConfig(new GenericRateLimiterConfig(10000000,
// 10000, 10));
// options.setRateLimiterConfig(new GenericRateLimiterConfig(10000000));
//
// Filter bloomFilter = new BloomFilter(10);
// BlockBasedTableConfig table_options = new BlockBasedTableConfig();
// table_options.setBlockCacheSize(64 * SizeUnit.KB)
// .setFilter(bloomFilter)
// .setCacheNumShardBits(6)
// .setBlockSizeDeviation(5)
// .setBlockRestartInterval(10)
// .setCacheIndexAndFilterBlocks(true)
// .setHashIndexAllowCollision(false)
// .setBlockCacheCompressedSize(64 * SizeUnit.KB)
// .setBlockCacheCompressedNumShardBits(10);
//
// assert(table_options.blockCacheSize() == 64 * SizeUnit.KB);
// assert(table_options.cacheNumShardBits() == 6);
// assert(table_options.blockSizeDeviation() == 5);
// assert(table_options.blockRestartInterval() == 10);
// assert(table_options.cacheIndexAndFilterBlocks() == true);
// assert(table_options.hashIndexAllowCollision() == false);
// assert(table_options.blockCacheCompressedSize() == 64 * SizeUnit.KB);
// assert(table_options.blockCacheCompressedNumShardBits() == 10);
//
// options.setTableFormatConfig(table_options);
// assert(options.tableFactoryName().equals("BlockBasedTable"));
try {
db = RocksDB.open(options, db_path);
db.put("hello".getBytes(), "world".getBytes());
byte[] value = db.get("hello".getBytes());
assert ("world".equals(new String(value)));
String str = db.getProperty("rocksdb.stats");
assert (str != null && str != "");
} catch (RocksDBException e) {
System.out.format("[ERROR] caught the unexpceted exception -- %s\n", e);
assert (db == null);
assert (false);
}
System.out.println("Initializing RocksDB is over");
}