com.facebook.presto.orc.OrcReader Maven / Gradle / Ivy
/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.facebook.presto.orc;
import com.facebook.presto.orc.memory.AbstractAggregatedMemoryContext;
import com.facebook.presto.orc.memory.AggregatedMemoryContext;
import com.facebook.presto.orc.metadata.CompressionKind;
import com.facebook.presto.orc.metadata.Footer;
import com.facebook.presto.orc.metadata.Metadata;
import com.facebook.presto.orc.metadata.MetadataReader;
import com.facebook.presto.orc.metadata.PostScript;
import com.facebook.presto.orc.stream.OrcInputStream;
import com.facebook.presto.spi.type.Type;
import com.google.common.base.Joiner;
import com.google.common.primitives.Ints;
import io.airlift.log.Logger;
import io.airlift.slice.Slice;
import io.airlift.slice.Slices;
import io.airlift.units.DataSize;
import org.joda.time.DateTimeZone;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.Map;
import static io.airlift.slice.SizeOf.SIZE_OF_BYTE;
import static java.lang.Math.min;
import static java.util.Objects.requireNonNull;
public class OrcReader
{
public static final int MAX_BATCH_SIZE = 1024;
private static final Logger log = Logger.get(OrcReader.class);
private static final Slice MAGIC = Slices.utf8Slice("ORC");
private static final int CURRENT_MAJOR_VERSION = 0;
private static final int CURRENT_MINOR_VERSION = 12;
private static final int EXPECTED_FOOTER_SIZE = 16 * 1024;
private final OrcDataSource orcDataSource;
private final MetadataReader metadataReader;
private final DataSize maxMergeDistance;
private final DataSize maxReadSize;
private final CompressionKind compressionKind;
private final int bufferSize;
private final Footer footer;
private final Metadata metadata;
// This is based on the Apache Hive ORC code
public OrcReader(OrcDataSource orcDataSource, MetadataReader metadataReader, DataSize maxMergeDistance, DataSize maxReadSize)
throws IOException
{
orcDataSource = wrapWithCacheIfTiny(requireNonNull(orcDataSource, "orcDataSource is null"), maxMergeDistance);
this.orcDataSource = orcDataSource;
this.metadataReader = requireNonNull(metadataReader, "metadataReader is null");
this.maxMergeDistance = requireNonNull(maxMergeDistance, "maxMergeDistance is null");
this.maxReadSize = requireNonNull(maxReadSize, "maxReadSize is null");
//
// Read the file tail:
//
// variable: Footer
// variable: Metadata
// variable: PostScript - contains length of footer and metadata
// 3 bytes: file magic "ORC"
// 1 byte: postScriptSize = PostScript + Magic
// figure out the size of the file using the option or filesystem
long size = orcDataSource.getSize();
if (size <= 0) {
throw new OrcCorruptionException("Malformed ORC file %s. Invalid file size %s", orcDataSource, size);
}
// Read the tail of the file
byte[] buffer = new byte[Ints.checkedCast(min(size, EXPECTED_FOOTER_SIZE))];
orcDataSource.readFully(size - buffer.length, buffer);
// get length of PostScript - last byte of the file
int postScriptSize = buffer[buffer.length - SIZE_OF_BYTE] & 0xff;
// make sure this is an ORC file and not an RCFile or something else
verifyOrcFooter(orcDataSource, postScriptSize, buffer);
// decode the post script
int postScriptOffset = buffer.length - SIZE_OF_BYTE - postScriptSize;
PostScript postScript = metadataReader.readPostScript(buffer, postScriptOffset, postScriptSize);
// verify this is a supported version
checkOrcVersion(orcDataSource, postScript.getVersion());
// check compression codec is supported
this.compressionKind = postScript.getCompression();
this.bufferSize = Ints.checkedCast(postScript.getCompressionBlockSize());
int footerSize = Ints.checkedCast(postScript.getFooterLength());
int metadataSize = Ints.checkedCast(postScript.getMetadataLength());
// check if extra bytes need to be read
Slice completeFooterSlice;
int completeFooterSize = footerSize + metadataSize + postScriptSize + SIZE_OF_BYTE;
if (completeFooterSize > buffer.length) {
// allocate a new buffer large enough for the complete footer
byte[] newBuffer = new byte[completeFooterSize];
completeFooterSlice = Slices.wrappedBuffer(newBuffer);
// initial read was not large enough, so read missing section
orcDataSource.readFully(size - completeFooterSize, newBuffer, 0, completeFooterSize - buffer.length);
// copy already read bytes into the new buffer
completeFooterSlice.setBytes(completeFooterSize - buffer.length, buffer);
}
else {
// footer is already in the bytes in buffer, just adjust position, length
completeFooterSlice = Slices.wrappedBuffer(buffer, buffer.length - completeFooterSize, completeFooterSize);
}
// read metadata
Slice metadataSlice = completeFooterSlice.slice(0, metadataSize);
try (InputStream metadataInputStream = new OrcInputStream(orcDataSource.toString(), metadataSlice.getInput(), compressionKind, bufferSize, new AggregatedMemoryContext())) {
this.metadata = metadataReader.readMetadata(metadataInputStream);
}
// read footer
Slice footerSlice = completeFooterSlice.slice(metadataSize, footerSize);
try (InputStream footerInputStream = new OrcInputStream(orcDataSource.toString(), footerSlice.getInput(), compressionKind, bufferSize, new AggregatedMemoryContext())) {
this.footer = metadataReader.readFooter(footerInputStream);
}
}
public List getColumnNames()
{
return footer.getTypes().get(0).getFieldNames();
}
public Footer getFooter()
{
return footer;
}
public Metadata getMetadata()
{
return metadata;
}
public CompressionKind getCompressionKind()
{
return compressionKind;
}
public int getBufferSize()
{
return bufferSize;
}
public OrcRecordReader createRecordReader(Map includedColumns, OrcPredicate predicate, DateTimeZone hiveStorageTimeZone, AbstractAggregatedMemoryContext systemMemoryUsage)
throws IOException
{
return createRecordReader(includedColumns, predicate, 0, orcDataSource.getSize(), hiveStorageTimeZone, systemMemoryUsage);
}
public OrcRecordReader createRecordReader(
Map includedColumns,
OrcPredicate predicate,
long offset,
long length,
DateTimeZone hiveStorageTimeZone,
AbstractAggregatedMemoryContext systemMemoryUsage)
throws IOException
{
return new OrcRecordReader(
requireNonNull(includedColumns, "includedColumns is null"),
requireNonNull(predicate, "predicate is null"),
footer.getNumberOfRows(),
footer.getStripes(),
footer.getFileStats(),
metadata.getStripeStatsList(),
orcDataSource,
offset,
length,
footer.getTypes(),
compressionKind,
bufferSize,
footer.getRowsInRowGroup(),
requireNonNull(hiveStorageTimeZone, "hiveStorageTimeZone is null"),
metadataReader,
maxMergeDistance,
maxReadSize,
footer.getUserMetadata(),
systemMemoryUsage);
}
private static OrcDataSource wrapWithCacheIfTiny(OrcDataSource dataSource, DataSize maxCacheSize)
{
if (dataSource instanceof CachingOrcDataSource) {
return dataSource;
}
if (dataSource.getSize() > maxCacheSize.toBytes()) {
return dataSource;
}
DiskRange diskRange = new DiskRange(0, Ints.checkedCast(dataSource.getSize()));
return new CachingOrcDataSource(dataSource, desiredOffset -> diskRange);
}
/**
* Verify this is an ORC file to prevent users from trying to read text
* files or RC files as ORC files.
*/
// This is based on the Apache Hive ORC code
private static void verifyOrcFooter(
OrcDataSource source,
int postScriptSize,
byte[] buffer)
throws IOException
{
int magicLength = MAGIC.length();
if (postScriptSize < magicLength + 1) {
throw new OrcCorruptionException("Malformed ORC file %s. Invalid postscript length %s", source, postScriptSize);
}
if (!MAGIC.equals(Slices.wrappedBuffer(buffer, buffer.length - 1 - magicLength, magicLength))) {
// Old versions of ORC (0.11) wrote the magic to the head of the file
byte[] headerMagic = new byte[magicLength];
source.readFully(0, headerMagic);
// if it isn't there, this isn't an ORC file
if (!MAGIC.equals(Slices.wrappedBuffer(headerMagic))) {
throw new OrcCorruptionException("Malformed ORC file %s. Invalid postscript.", source);
}
}
}
/**
* Check to see if this ORC file is from a future version and if so,
* warn the user that we may not be able to read all of the column encodings.
*/
// This is based on the Apache Hive ORC code
private static void checkOrcVersion(OrcDataSource orcDataSource, List version)
{
if (version.size() >= 1) {
int major = version.get(0);
int minor = 0;
if (version.size() > 1) {
minor = version.get(1);
}
if (major > CURRENT_MAJOR_VERSION || (major == CURRENT_MAJOR_VERSION && minor > CURRENT_MINOR_VERSION)) {
log.warn("ORC file %s was written by a newer Hive version %s. This file may not be readable by this version of Hive (%s.%s).",
orcDataSource,
Joiner.on('.').join(version),
CURRENT_MAJOR_VERSION,
CURRENT_MINOR_VERSION);
}
}
}
}
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