/**
* Returns statistics on this table as a tabular result set. Used for the SHOW TABLE STATS
* statement. The schema of the returned TResultSet is set inside this method.
*/
public TResultSet getTableStats() {
TResultSet result = new TResultSet();
TResultSetMetadata resultSchema = new TResultSetMetadata();
result.setSchema(resultSchema);
for (int i = 0; i < numClusteringCols_; ++i) {
// Add the partition-key values as strings for simplicity.
Column partCol = colsByPos_.get(i);
TColumn colDesc = new TColumn(partCol.getName(), partCol.getType().toThrift());
resultSchema.addToColumns(colDesc);
}
resultSchema.addToColumns(new TColumn("#Rows", ColumnType.BIGINT.toThrift()));
resultSchema.addToColumns(new TColumn("#Files", ColumnType.BIGINT.toThrift()));
resultSchema.addToColumns(new TColumn("Size", ColumnType.STRING.toThrift()));
resultSchema.addToColumns(new TColumn("Format", ColumnType.STRING.toThrift()));
// Pretty print partitions and their stats.
ArrayList<HdfsPartition> orderedPartitions = Lists.newArrayList(partitions_);
Collections.sort(orderedPartitions);
for (HdfsPartition p : orderedPartitions) {
// Ignore dummy default partition.
if (p.getId() == ImpalaInternalServiceConstants.DEFAULT_PARTITION_ID) continue;
TResultRowBuilder rowBuilder = new TResultRowBuilder();
// Add the partition-key values (as strings for simplicity).
for (LiteralExpr expr : p.getPartitionValues()) {
rowBuilder.add(expr.getStringValue());
}
// Add number of rows, files, bytes and the file format.
rowBuilder
.add(p.getNumRows())
.add(p.getFileDescriptors().size())
.addBytes(p.getSize())
.add(p.getInputFormatDescriptor().getFileFormat().toString());
result.addToRows(rowBuilder.get());
}
// For partitioned tables add a summary row at the bottom.
if (numClusteringCols_ > 0) {
TResultRowBuilder rowBuilder = new TResultRowBuilder();
int numEmptyCells = numClusteringCols_ - 1;
rowBuilder.add("Total");
for (int i = 0; i < numEmptyCells; ++i) {
rowBuilder.add("");
}
// Total num rows, files, and bytes (leave format empty).
rowBuilder.add(numRows_).add(numHdfsFiles_).addBytes(totalHdfsBytes_).add("");
result.addToRows(rowBuilder.get());
}
return result;
}
/**
* Returns statistics on this table as a tabular result set. Used for the SHOW TABLE STATS
* statement. The schema of the returned TResultSet is set inside this method.
*/
public TResultSet getTableStats() {
TResultSet result = new TResultSet();
TResultSetMetadata resultSchema = new TResultSetMetadata();
result.setSchema(resultSchema);
resultSchema.addToColumns(new TColumn("Region Location", ColumnType.STRING.toThrift()));
resultSchema.addToColumns(new TColumn("Start RowKey", ColumnType.STRING.toThrift()));
resultSchema.addToColumns(new TColumn("Est. #Rows", ColumnType.BIGINT.toThrift()));
resultSchema.addToColumns(new TColumn("Size", ColumnType.STRING.toThrift()));
// TODO: Consider fancier stats maintenance techniques for speeding up this process.
// Currently, we list all regions and perform a mini-scan of each of them to
// estimate the number of rows, the data size, etc., which is rather expensive.
try {
long totalNumRows = 0;
long totalHdfsSize = 0;
List<HRegionLocation> regions =
HBaseTable.getRegionsInRange(
hTable_, HConstants.EMPTY_END_ROW, HConstants.EMPTY_START_ROW);
for (HRegionLocation region : regions) {
TResultRowBuilder rowBuilder = new TResultRowBuilder();
HRegionInfo regionInfo = region.getRegionInfo();
Pair<Long, Long> estRowStats =
getEstimatedRowStats(regionInfo.getStartKey(), regionInfo.getEndKey());
long numRows = estRowStats.first.longValue();
long hdfsSize = getHdfsSize(regionInfo);
totalNumRows += numRows;
totalHdfsSize += hdfsSize;
// Add the region location, start rowkey, number of rows and raw Hdfs size.
rowBuilder
.add(String.valueOf(region.getHostname()))
.add(Bytes.toString(regionInfo.getStartKey()))
.add(numRows)
.addBytes(hdfsSize);
result.addToRows(rowBuilder.get());
}
// Total num rows and raw Hdfs size.
if (regions.size() > 1) {
TResultRowBuilder rowBuilder = new TResultRowBuilder();
rowBuilder.add("Total").add("").add(totalNumRows).addBytes(totalHdfsSize);
result.addToRows(rowBuilder.get());
}
} catch (IOException e) {
throw new RuntimeException(e);
}
return result;
}