private void ensureMetadataReader() throws IOException {
ensureOrcReader();
if (metadataReader != null) return;
long startTime = counters.startTimeCounter();
metadataReader = orcReader.metadata();
counters.incrTimeCounter(Counter.HDFS_TIME_US, startTime);
}
/** Ensures orcReader is initialized for the split. */
private void ensureOrcReader() throws IOException {
if (orcReader != null) return;
Path path = HdfsUtils.getFileIdPath(fs, split.getPath(), fileId);
if (DebugUtils.isTraceOrcEnabled()) {
LOG.info("Creating reader for " + path + " (" + split.getPath() + ")");
}
long startTime = counters.startTimeCounter();
ReaderOptions opts = OrcFile.readerOptions(conf).filesystem(fs).fileMetadata(fileMetadata);
orcReader = EncodedOrcFile.createReader(path, opts);
counters.incrTimeCounter(Counter.HDFS_TIME_US, startTime);
}
/**
* In case if stripe metadata in cache does not have all indexes for current query, load the
* missing one. This is a temporary cludge until real metadata cache becomes available.
*/
private void updateLoadedIndexes(
OrcStripeMetadata stripeMetadata,
StripeInformation stripe,
boolean[] stripeIncludes,
boolean[] sargColumns)
throws IOException {
// We only synchronize on write for now - design of metadata cache is very temporary;
// we pre-allocate the array and never remove entries; so readers should be safe.
synchronized (stripeMetadata) {
if (stripeMetadata.hasAllIndexes(stripeIncludes)) return;
long startTime = counters.startTimeCounter();
stripeMetadata.loadMissingIndexes(metadataReader, stripe, stripeIncludes, sargColumns);
counters.incrTimeCounter(Counter.HDFS_TIME_US, startTime);
}
}
/** Reads the metadata for all stripes in the file. */
private ArrayList<OrcStripeMetadata> readStripesMetadata(
boolean[] globalInc, boolean[] sargColumns) throws IOException {
ArrayList<OrcStripeMetadata> result = new ArrayList<OrcStripeMetadata>(readState.length);
OrcBatchKey stripeKey = new OrcBatchKey(fileId, 0, 0);
for (int stripeIxMod = 0; stripeIxMod < readState.length; ++stripeIxMod) {
stripeKey.stripeIx = stripeIxMod + stripeIxFrom;
OrcStripeMetadata value = metadataCache.getStripeMetadata(stripeKey);
if (value == null || !value.hasAllIndexes(globalInc)) {
counters.incrCounter(Counter.METADATA_CACHE_MISS);
ensureMetadataReader();
StripeInformation si = fileMetadata.getStripes().get(stripeKey.stripeIx);
if (value == null) {
long startTime = counters.startTimeCounter();
value = new OrcStripeMetadata(stripeKey, metadataReader, si, globalInc, sargColumns);
counters.incrTimeCounter(Counter.HDFS_TIME_US, startTime);
value = metadataCache.putStripeMetadata(value);
if (DebugUtils.isTraceOrcEnabled()) {
LlapIoImpl.LOG.info(
"Caching stripe "
+ stripeKey.stripeIx
+ " metadata with includes: "
+ DebugUtils.toString(globalInc));
}
// Create new key object to reuse for gets; we've used the old one to put in cache.
stripeKey = new OrcBatchKey(fileId, 0, 0);
}
// We might have got an old value from cache; recheck it has indexes.
if (!value.hasAllIndexes(globalInc)) {
if (DebugUtils.isTraceOrcEnabled()) {
LlapIoImpl.LOG.info(
"Updating indexes in stripe "
+ stripeKey.stripeIx
+ " metadata for includes: "
+ DebugUtils.toString(globalInc));
}
updateLoadedIndexes(value, si, globalInc, sargColumns);
}
} else {
counters.incrCounter(Counter.METADATA_CACHE_HIT);
}
result.add(value);
consumer.setStripeMetadata(value);
}
return result;
}
protected Void performDataRead() throws IOException {
long startTime = counters.startTimeCounter();
if (LlapIoImpl.LOGL.isInfoEnabled()) {
LlapIoImpl.LOG.info("Processing data for " + split.getPath());
}
if (processStop()) {
recordReaderTime(startTime);
return null;
}
counters.setDesc(QueryFragmentCounters.Desc.TABLE, getDbAndTableName(split.getPath()));
orcReader = null;
// 1. Get file metadata from cache, or create the reader and read it.
// Don't cache the filesystem object for now; Tez closes it and FS cache will fix all that
fs = split.getPath().getFileSystem(conf);
fileId = determineFileId(fs, split);
counters.setDesc(QueryFragmentCounters.Desc.FILE, fileId);
try {
fileMetadata = getOrReadFileMetadata();
consumer.setFileMetadata(fileMetadata);
validateFileMetadata();
if (columnIds == null) {
columnIds = createColumnIds(fileMetadata);
}
// 2. Determine which stripes to read based on the split.
determineStripesToRead();
} catch (Throwable t) {
recordReaderTime(startTime);
consumer.setError(t);
return null;
}
if (readState.length == 0) {
consumer.setDone();
recordReaderTime(startTime);
return null; // No data to read.
}
counters.setDesc(QueryFragmentCounters.Desc.STRIPES, stripeIxFrom + "," + readState.length);
// 3. Apply SARG if needed, and otherwise determine what RGs to read.
int stride = fileMetadata.getRowIndexStride();
ArrayList<OrcStripeMetadata> stripeMetadatas = null;
boolean[] globalIncludes = null;
boolean[] sargColumns = null;
try {
globalIncludes = OrcInputFormat.genIncludedColumns(fileMetadata.getTypes(), columnIds, true);
if (sarg != null && stride != 0) {
// TODO: move this to a common method
int[] filterColumns =
RecordReaderImpl.mapSargColumnsToOrcInternalColIdx(sarg.getLeaves(), columnNames, 0);
// included will not be null, row options will fill the array with trues if null
sargColumns = new boolean[globalIncludes.length];
for (int i : filterColumns) {
// filter columns may have -1 as index which could be partition column in SARG.
if (i > 0) {
sargColumns[i] = true;
}
}
// If SARG is present, get relevant stripe metadata from cache or readers.
stripeMetadatas = readStripesMetadata(globalIncludes, sargColumns);
}
// Now, apply SARG if any; w/o sarg, this will just initialize readState.
boolean hasData = determineRgsToRead(globalIncludes, stride, stripeMetadatas);
if (!hasData) {
consumer.setDone();
recordReaderTime(startTime);
return null; // No data to read.
}
} catch (Throwable t) {
cleanupReaders();
consumer.setError(t);
recordReaderTime(startTime);
return null;
}
if (processStop()) {
cleanupReaders();
recordReaderTime(startTime);
return null;
}
// 4. Get data from high-level cache.
// If some cols are fully in cache, this will also give us the modified list of columns to
// read for every stripe (null means read all of them - the usual path). In any case,
// readState will be modified for column x rgs that were fetched from high-level cache.
List<Integer>[] stripeColsToRead = null;
if (cache != null) {
try {
stripeColsToRead = produceDataFromCache(stride);
} catch (Throwable t) {
// produceDataFromCache handles its own cleanup.
consumer.setError(t);
cleanupReaders();
recordReaderTime(startTime);
return null;
}
}
// 5. Create encoded data reader.
// In case if we have high-level cache, we will intercept the data and add it there;
// otherwise just pass the data directly to the consumer.
Consumer<OrcEncodedColumnBatch> dataConsumer = (cache == null) ? this.consumer : this;
try {
ensureOrcReader();
// Reader creating updates HDFS counters, don't do it here.
DataWrapperForOrc dw = new DataWrapperForOrc();
stripeReader = orcReader.encodedReader(fileId, dw, dw, POOL_FACTORY);
stripeReader.setDebugTracing(DebugUtils.isTraceOrcEnabled());
} catch (Throwable t) {
consumer.setError(t);
recordReaderTime(startTime);
cleanupReaders();
return null;
}
// 6. Read data.
// TODO: I/O threadpool could be here - one thread per stripe; for now, linear.
OrcBatchKey stripeKey = new OrcBatchKey(fileId, -1, 0);
for (int stripeIxMod = 0; stripeIxMod < readState.length; ++stripeIxMod) {
if (processStop()) {
cleanupReaders();
recordReaderTime(startTime);
return null;
}
int stripeIx = stripeIxFrom + stripeIxMod;
boolean[][] colRgs = null;
boolean[] stripeIncludes = null;
OrcStripeMetadata stripeMetadata = null;
StripeInformation stripe;
try {
List<Integer> cols = stripeColsToRead == null ? null : stripeColsToRead[stripeIxMod];
if (cols != null && cols.isEmpty()) continue; // No need to read this stripe.
stripe = fileMetadata.getStripes().get(stripeIx);
if (DebugUtils.isTraceOrcEnabled()) {
LlapIoImpl.LOG.info(
"Reading stripe " + stripeIx + ": " + stripe.getOffset() + ", " + stripe.getLength());
}
colRgs = readState[stripeIxMod];
// We assume that NO_RGS value is only set from SARG filter and for all columns;
// intermediate changes for individual columns will unset values in the array.
// Skip this case for 0-column read. We could probably special-case it just like we do
// in EncodedReaderImpl, but for now it's not that important.
if (colRgs.length > 0 && colRgs[0] == SargApplier.READ_NO_RGS) continue;
// 6.1. Determine the columns to read (usually the same as requested).
if (cache == null || cols == null || cols.size() == colRgs.length) {
cols = columnIds;
stripeIncludes = globalIncludes;
} else {
// We are reading subset of the original columns, remove unnecessary bitmasks/etc.
// This will never happen w/o high-level cache.
stripeIncludes = OrcInputFormat.genIncludedColumns(fileMetadata.getTypes(), cols, true);
colRgs = genStripeColRgs(cols, colRgs);
}
// 6.2. Ensure we have stripe metadata. We might have read it before for RG filtering.
boolean isFoundInCache = false;
if (stripeMetadatas != null) {
stripeMetadata = stripeMetadatas.get(stripeIxMod);
} else {
stripeKey.stripeIx = stripeIx;
stripeMetadata = metadataCache.getStripeMetadata(stripeKey);
isFoundInCache = (stripeMetadata != null);
if (!isFoundInCache) {
counters.incrCounter(Counter.METADATA_CACHE_MISS);
ensureMetadataReader();
long startTimeHdfs = counters.startTimeCounter();
stripeMetadata =
new OrcStripeMetadata(
stripeKey, metadataReader, stripe, stripeIncludes, sargColumns);
counters.incrTimeCounter(Counter.HDFS_TIME_US, startTimeHdfs);
stripeMetadata = metadataCache.putStripeMetadata(stripeMetadata);
if (DebugUtils.isTraceOrcEnabled()) {
LlapIoImpl.LOG.info(
"Caching stripe "
+ stripeKey.stripeIx
+ " metadata with includes: "
+ DebugUtils.toString(stripeIncludes));
}
stripeKey = new OrcBatchKey(fileId, -1, 0);
}
consumer.setStripeMetadata(stripeMetadata);
}
if (!stripeMetadata.hasAllIndexes(stripeIncludes)) {
if (DebugUtils.isTraceOrcEnabled()) {
LlapIoImpl.LOG.info(
"Updating indexes in stripe "
+ stripeKey.stripeIx
+ " metadata for includes: "
+ DebugUtils.toString(stripeIncludes));
}
assert isFoundInCache;
counters.incrCounter(Counter.METADATA_CACHE_MISS);
ensureMetadataReader();
updateLoadedIndexes(stripeMetadata, stripe, stripeIncludes, sargColumns);
} else if (isFoundInCache) {
counters.incrCounter(Counter.METADATA_CACHE_HIT);
}
} catch (Throwable t) {
consumer.setError(t);
cleanupReaders();
recordReaderTime(startTime);
return null;
}
if (processStop()) {
cleanupReaders();
recordReaderTime(startTime);
return null;
}
// 6.3. Finally, hand off to the stripe reader to produce the data.
// This is a sync call that will feed data to the consumer.
try {
// TODO: readEncodedColumns is not supposed to throw; errors should be propagated thru
// consumer. It is potentially holding locked buffers, and must perform its own cleanup.
// Also, currently readEncodedColumns is not stoppable. The consumer will discard the
// data it receives for one stripe. We could probably interrupt it, if it checked that.
stripeReader.readEncodedColumns(
stripeIx,
stripe,
stripeMetadata.getRowIndexes(),
stripeMetadata.getEncodings(),
stripeMetadata.getStreams(),
stripeIncludes,
colRgs,
dataConsumer);
} catch (Throwable t) {
consumer.setError(t);
cleanupReaders();
recordReaderTime(startTime);
return null;
}
}
// Done with all the things.
recordReaderTime(startTime);
dataConsumer.setDone();
if (DebugUtils.isTraceMttEnabled()) {
LlapIoImpl.LOG.info("done processing " + split);
}
// Close the stripe reader, we are done reading.
cleanupReaders();
return null;
}