com.indeed.mph.TableReader Maven / Gradle / Ivy
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package com.indeed.mph;
import com.indeed.util.core.Pair;
import com.indeed.util.mmap.HeapMemory;
import com.indeed.util.mmap.MMapBuffer;
import com.indeed.util.mmap.Memory;
import com.indeed.util.mmap.MemoryDataInput;
import it.unimi.dsi.sux4j.bits.HintedBsearchSelect;
import it.unimi.dsi.sux4j.bits.Rank9;
import it.unimi.dsi.sux4j.bits.Select;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.io.BufferedReader;
import java.io.Closeable;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileReader;
import java.io.IOException;
import java.nio.ByteOrder;
import java.nio.channels.FileChannel;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.concurrent.atomic.AtomicLong;
/**
* Class to read from arbitrary mph tables. Mph tables are
* self-descriptive, so no config is needed. Use SharedTableReader if
* you need to use the same reader from multiple threads.
*
* Example:
*
*
* try (final TableReader<KeyClass, ValueClass> reader = TableReader.open(dir)) {
* final ValueClass value = reader.get(key);
* }
*
*
* As a convenience, the main method lets you query existing tables
* from the command line:
*
* java com.indeed.mph.TableReader [options] table_dir [keys.txt]
*
* where options are
*
* --info: print the meta info
* --dump: print the key/values of the entire table as TSV
* --get key: print the value for a specific key
* --random: print the value for a randomly generated long
*
* otherwise prints all values for the associated keys taken from
* keys.txt (defaulting to stdin). Additional options useful for
* benchmarking are:
*
* --time: print the time taken to finish all reads
* --quiet: don't actually print the values
* --repeat n: repeat the read n times
* --threads n: duplicate all reads simultaneously among n threads
*
* @author alexs
*/
public class TableReader implements Closeable, Iterable> {
private final TableMeta meta;
private final MMapBuffer offsets;
private final Memory memory;
private final Select select;
private MMapBuffer data;
private Memory dataMemory;
private final AtomicLong filteredCount = new AtomicLong(0L);
private final AtomicLong missingCount = new AtomicLong(0L);
private final AtomicLong retrievedCount = new AtomicLong(0L);
public TableReader(@Nonnull final TableMeta meta,
@Nonnull final byte[] rawData) {
this.meta = meta;
dataMemory = new HeapMemory(rawData, ByteOrder.nativeOrder());
data = null;
offsets = null;
select = null;
memory = null;
}
public TableReader(@Nonnull final TableMeta meta,
@Nonnull final MMapBuffer data,
@Nullable final MMapBuffer offsets) {
this.meta = meta;
this.data = data;
this.dataMemory = data.memory();
this.offsets = offsets;
if (offsets != null) {
if (TableConfig.OffsetStorage.SELECTED.equals(meta.getConfig().getOffsetStorage())) {
select = new HintedBsearchSelect(new Rank9(new MMapBitVector(offsets)));
memory = null;
} else {
select = null;
memory = offsets.memory();
}
} else {
select = null;
memory = null;
}
}
@Override
public void close() throws IOException {
if (offsets != null) offsets.close();
if (data != null) data.close();
data = null;
dataMemory = null;
}
/**
* General interface to opening a TableReader. Only the metaPath
* is required, variants below are conveniences with default
* parameters.
*
* @param metaPath path to the table's meta-data, either the exact file or the containing directory
* @param offsetsPath path to the raw offsets if different from the meta-data setting
* @param dataPath path to the raw serialized data if different from the meta-data setting
* @param maxDataHeapUsage if specified and positive, raw data less than this size will be
* stored directly in the heap instead of mmaped
* @param key type
* @param value type
* @return a new TableReader on the data
* @throws IOException if unable to open any of the files, or deserialize the metadata
*/
public static TableReader open(@Nonnull final File metaPath,
@Nullable final File offsetsPath,
@Nullable final File dataPath,
@Nullable final Long maxDataHeapUsage) throws IOException {
final TableMeta meta = TableMeta.load(metaPath, offsetsPath, dataPath);
final MMapBuffer data =
new MMapBuffer(meta.getDataPath(), FileChannel.MapMode.READ_ONLY, ByteOrder.nativeOrder());
final MMapBuffer offsets = TableConfig.OffsetStorage.INDEXED.equals(meta.getConfig().getOffsetStorage()) ||
(TableConfig.OffsetStorage.SELECTED.equals(meta.getConfig().getOffsetStorage()) && meta.getSelectOffsets() == null) ?
new MMapBuffer(meta.getOffsetsPath(), FileChannel.MapMode.READ_ONLY, ByteOrder.nativeOrder()) :
null;
final long maxDataHeap =
maxDataHeapUsage != null ? maxDataHeapUsage : meta.getConfig().getMaxDataHeapUsage();
if (offsets == null && data.memory().length() < maxDataHeap) {
final byte[] rawData = new byte[(int) data.memory().length()];
data.memory().getBytes(0, rawData);
data.close();
return new TableReader(meta, rawData);
} else {
return new TableReader(meta, data, offsets);
}
}
public static TableReader open(@Nonnull final File metaPath, @Nullable final File offsetsPath, @Nullable final File dataPath) throws IOException {
return open(metaPath, offsetsPath, dataPath, null);
}
public static TableReader open(@Nonnull final File metaPath, @Nullable final Long maxDataHeapUsage) throws IOException {
return open(metaPath, null, null, maxDataHeapUsage);
}
public static TableReader open(@Nonnull final File metaPath) throws IOException {
return open(metaPath, null, null, null);
}
public static TableReader open(@Nonnull final String metaPath) throws IOException {
return open(new File(metaPath));
}
public static TableReader open(@Nonnull final String metaPath, @Nullable final Long maxDataHeapUsage) throws IOException {
return open(new File(metaPath), maxDataHeapUsage);
}
public boolean isDiskBased() {
return data != null || memory != null;
}
public TableMeta getMeta() {
return meta;
}
public TableConfig getConfig() {
return meta.getConfig();
}
public TableStats getStats() {
return new TableStats(filteredCount.get(), missingCount.get(), retrievedCount.get());
}
public boolean containsKey(@Nonnull final K key) {
try {
if (meta.getConfig().getKeyValidator() == null) {
return getOffset(key) >= 0;
}
return get(key) != null;
} catch (final IOException e) {
return false;
}
}
public V get(@Nonnull final K key) throws IOException {
if (dataMemory == null) {
throw new IOException("table has been closed!");
}
final long offset = getOffset(key);
if (offset < 0) {
filteredCount.incrementAndGet();
return null;
}
final MemoryDataInput in = new MemoryDataInput(dataMemory);
in.seek(offset);
final TableConfig config = meta.getConfig();
final K extractedKey = config.readKey(in);
final V value = config.readValue(in);
if (config.getKeyValidator() != null) {
final V result = config.getKeyValidator().validate(key, extractedKey, value);
if (result == null) {
missingCount.incrementAndGet();
} else {
retrievedCount.incrementAndGet();
}
return result;
}
retrievedCount.incrementAndGet();
return value;
}
// no validation other than range, just get the value associated with the hash
public MemoryDataInput getMemoryForHash(final long hash) throws IOException {
if (dataMemory == null) {
throw new IOException("table has been closed!");
}
if (hash < 0 || hash >= size()) {
return null;
}
final long offset = getHashOffset(hash);
if (offset < 0) {
return null;
}
final MemoryDataInput in = new MemoryDataInput(dataMemory);
in.seek(offset);
return in;
}
public K getKeyForHash(final long hash) throws IOException {
final MemoryDataInput in = getMemoryForHash(hash);
if (in == null) {
return null;
}
return meta.getConfig().readKey(in);
}
public V getForHash(final long hash) throws IOException {
final MemoryDataInput in = getMemoryForHash(hash);
if (in == null) {
return null;
}
meta.getConfig().readKey(in);
return meta.getConfig().readValue(in);
}
public long getHash(@Nonnull final K key) {
return meta.getHash(key);
}
public long getOffset(@Nonnull final K key) {
return meta.getOffset(key, memory, select);
}
public long getHashOffset(final long hash) {
return meta.getHashOffset(hash, memory, select);
}
public long size() {
return meta.numEntries();
}
public long getSizeInBytes() {
return meta.getSizeInBytes();
}
public long getTimestamp() {
return meta.getTimestamp();
}
public TableIterator iterator() {
return new TableIterator();
}
public class TableIterator implements Iterator> {
private final MemoryDataInput in;
private long hash;
public TableIterator() {
in = new MemoryDataInput(dataMemory);
hash = 0;
}
@Override
public boolean hasNext() {
return hash < meta.numEntries();
}
@Override
public Pair next() {
final long offset = meta.getHashOffset(hash++, memory, select);
try {
in.seek(offset);
final TableConfig config = meta.getConfig();
final K extractedKey = config.readKey(in);
final V value = config.readValue(in);
return new Pair<>(extractedKey, value);
} catch (final IOException e) {
throw new RuntimeException("error reading from TableIterator: " + offset, e);
}
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}
public static class TableStats {
public final long filteredCount;
public final long missingCount;
public final long retrievedCount;
public TableStats(final long filteredCount, final long missingCount, final long retrievedCount) {
this.filteredCount = filteredCount;
this.missingCount = missingCount;
this.retrievedCount = retrievedCount;
}
public String toString() {
final long total = filteredCount + missingCount + retrievedCount;
if (total == 0) {
return "[filtered: 0 missing: 0 retrived: 0]";
}
return "[filtered: " + filteredCount + " (" + (100.0 * filteredCount / total) +
"%) missing: " + missingCount + " (" + (100.0 * missingCount / total) +
"%) retrieved: " + retrievedCount + " (" + (100.0 * retrievedCount / total) +"%)]";
}
}
public static void main(final String[] args) throws IOException, InterruptedException {
String keyStr = null;
boolean quiet = false;
boolean info = false;
boolean dump = false;
boolean time = false;
boolean random = false;
int repetitions = 1;
int threads = 1;
int i = 0;
parse_opts:
for ( ; i < args.length && args[i].startsWith("-"); ++i) {
switch (args[i]) {
case "--": break parse_opts;
case "--dump": dump = true; break;
case "--info": info = true; break;
case "--quiet": quiet = true; break;
case "--time": time = true; break;
case "--random": random = true; break;
case "--get": keyStr = args[++i]; break;
case "--repeat": repetitions = Integer.parseInt(args[++i]); break;
case "--threads": threads = Integer.parseInt(args[++i]); break;
default: throw new RuntimeException("unknown option: " + args[i]);
}
}
if (args.length - i < 1) {
throw new RuntimeException("usage: TableReader [--dump|--info|--quiet|--time|--random|--repeat n|--threads n|--get k] []");
}
final File tablePath = new File(args[i]);
final String keyInput = keyStr != null || random || i + 1 >= args.length ? null : args[i + 1];
if (info || dump) {
try (final TableReader reader = TableReader.open(tablePath)) {
if (info) {
System.out.println(reader.meta);
}
if (dump) {
final TableConfig config = reader.getConfig();
for (final Pair entry : reader) {
System.out.println(config.getKeySerializer().printToString(entry.getFirst()) + "\t" +
(config.getValueSerializer() == null ? null :
config.getValueSerializer().printToString(entry.getSecond())));
}
}
}
return;
}
final List workers = new ArrayList();
final int reps = repetitions;
final boolean rand = random;
final boolean quietly = quiet;
final long startTime = System.currentTimeMillis();
try (final TableReader reader = TableReader.open(tablePath)) {
final TableConfig config = reader.getConfig();
final Object defaultKey = keyStr != null ? config.getKeySerializer().parseFromString(keyStr) : null;
for (int t = 0; t < threads; ++t) {
workers.add(new Thread() {
public void run() {
final Random rng = new Random();
try {
final Object key = defaultKey != null ? defaultKey : rand ? rng.nextLong() : null;
for (int j = 0; j < reps; ++j) {
if (key != null) {
final Object value = reader.get(key);
if (!quietly) {
System.out.println(config.getValueSerializer().printToString(value));
}
} else {
try (final BufferedReader in = new BufferedReader(
keyInput == null ? new FileReader(FileDescriptor.in) : new FileReader(keyInput))) {
while (true) {
final String line = in.readLine();
if (line == null) {
break;
}
final Object value = reader.get(config.getKeySerializer().parseFromString(line));
if (!quietly) {
System.out.println(config.getValueSerializer().printToString(value));
}
}
}
}
}
} catch (final IOException e) {
throw new RuntimeException("error reading table", e);
}
}
});
}
for (final Thread worker : workers) {
worker.start();
}
for (final Thread worker : workers) {
worker.join();
}
}
if (time) {
System.out.println("read complete in " + (System.currentTimeMillis() - startTime) + " ms");
}
}
}