85 lines
2.4 KiB
Java
85 lines
2.4 KiB
Java
package it.cavallium.dbengine.database.disk;
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import it.cavallium.dbengine.database.LLRange;
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import java.util.Optional;
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import org.rocksdb.ColumnFamilyHandle;
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import org.rocksdb.ReadOptions;
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import org.rocksdb.RocksDB;
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import org.rocksdb.RocksMutableObject;
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import org.rocksdb.Slice;
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import reactor.core.publisher.Flux;
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import reactor.util.function.Tuples;
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public abstract class LLLocalReactiveRocksIterator<T> {
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private static final byte[] EMPTY = new byte[0];
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private final RocksDB db;
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private final ColumnFamilyHandle cfh;
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private final LLRange range;
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private final ReadOptions readOptions;
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private final boolean readValues;
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public LLLocalReactiveRocksIterator(RocksDB db,
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ColumnFamilyHandle cfh,
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LLRange range,
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ReadOptions readOptions,
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boolean readValues) {
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this.db = db;
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this.cfh = cfh;
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this.range = range;
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this.readOptions = readOptions;
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this.readValues = readValues;
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}
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public Flux<T> flux() {
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return Flux
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.generate(() -> {
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var readOptions = new ReadOptions(this.readOptions);
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if (!range.hasMin() || !range.hasMax()) {
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readOptions.setReadaheadSize(2 * 1024 * 1024);
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readOptions.setFillCache(false);
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}
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Slice sliceMin;
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Slice sliceMax;
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if (range.hasMin()) {
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sliceMin = new Slice(range.getMin());
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readOptions.setIterateLowerBound(sliceMin);
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} else {
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sliceMin = null;
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}
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if (range.hasMax()) {
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sliceMax = new Slice(range.getMax());
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readOptions.setIterateUpperBound(sliceMax);
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} else {
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sliceMax = null;
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}
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var rocksIterator = db.newIterator(cfh, readOptions);
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if (!LLLocalDictionary.PREFER_SEEK_TO_FIRST && range.hasMin()) {
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rocksIterator.seek(range.getMin());
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} else {
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rocksIterator.seekToFirst();
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}
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return Tuples.of(rocksIterator, Optional.ofNullable(sliceMin), Optional.ofNullable(sliceMax));
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}, (tuple, sink) -> {
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var rocksIterator = tuple.getT1();
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if (rocksIterator.isValid()) {
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byte[] key = rocksIterator.key();
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byte[] value = readValues ? rocksIterator.value() : EMPTY;
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rocksIterator.next();
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sink.next(getEntry(key, value));
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} else {
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sink.complete();
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}
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return tuple;
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}, tuple -> {
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var rocksIterator = tuple.getT1();
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rocksIterator.close();
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tuple.getT2().ifPresent(RocksMutableObject::close);
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tuple.getT3().ifPresent(RocksMutableObject::close);
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});
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}
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public abstract T getEntry(byte[] key, byte[] value);
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}
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