@Override
public LogicalNode visitScan(
CompilationContext context,
LogicalPlan plan,
LogicalPlan.QueryBlock block,
ScanNode node,
Stack<LogicalNode> stack)
throws TajoException {
compileProjectableNode(context, node.getInSchema(), node);
compileSelectableNode(context, node.getInSchema(), node);
return node;
}
public SystemPhysicalExec(TaskAttemptContext context, ScanNode scanNode) {
super(context, scanNode.getInSchema(), scanNode.getOutSchema());
this.scanNode = scanNode;
if (this.scanNode.hasQual()) {
this.qual = this.scanNode.getQual();
this.qual.bind(null, inSchema);
}
cachedData = TUtil.newList();
currentRow = 0;
isClosed = false;
projector = new Projector(context, inSchema, outSchema, scanNode.getTargets());
}
@Override
public Tuple next() throws IOException {
Tuple aTuple;
Tuple outTuple = new VTuple(outColumnNum);
if (isClosed) {
return null;
}
if (cachedData.size() == 0) {
rescan();
}
if (!scanNode.hasQual()) {
if (currentRow < cachedData.size()) {
aTuple = cachedData.get(currentRow++);
projector.eval(aTuple, outTuple);
outTuple.setOffset(aTuple.getOffset());
return outTuple;
}
return null;
} else {
while (currentRow < cachedData.size()) {
aTuple = cachedData.get(currentRow++);
if (qual.eval(aTuple).isTrue()) {
projector.eval(aTuple, outTuple);
return outTuple;
}
}
return null;
}
}
public void execSimpleQuery(
QueryContext queryContext,
Session session,
String query,
LogicalPlan plan,
SubmitQueryResponse.Builder response)
throws Exception {
ScanNode scanNode = plan.getRootBlock().getNode(NodeType.SCAN);
TableDesc desc = scanNode.getTableDesc();
if (desc.hasPartition()) {
scanNode = plan.getRootBlock().getNode(NodeType.PARTITIONS_SCAN);
}
int maxRow = Integer.MAX_VALUE;
if (plan.getRootBlock().hasNode(NodeType.LIMIT)) {
LimitNode limitNode = plan.getRootBlock().getNode(NodeType.LIMIT);
maxRow = (int) limitNode.getFetchFirstNum();
}
if (desc.getStats().getNumRows() == 0) {
desc.getStats().setNumRows(TajoConstants.UNKNOWN_ROW_NUMBER);
}
QueryInfo queryInfo =
context
.getQueryJobManager()
.createNewSimpleQuery(
queryContext, session, query, (LogicalRootNode) plan.getRootBlock().getRoot());
NonForwardQueryResultScanner queryResultScanner =
new NonForwardQueryResultFileScanner(
context.getConf(),
session.getSessionId(),
queryInfo.getQueryId(),
scanNode,
desc,
maxRow);
queryResultScanner.init();
session.addNonForwardQueryResultScanner(queryResultScanner);
response.setState(OK);
response.setQueryId(queryInfo.getQueryId().getProto());
response.setResultType(ResultType.ENCLOSED);
response.setMaxRowNum(maxRow);
response.setTableDesc(desc.getProto());
}
@Override
public void rescan() throws IOException {
cachedData.clear();
cachedData.addAll(fetchSystemTable(scanNode.getTableDesc(), inSchema));
tableStats = new TableStats();
tableStats.setNumRows(cachedData.size());
}
@Override
protected void compile() throws CompilationError {
if (scanNode.hasQual()) {
qual = context.getPrecompiledEval(inSchema, qual);
}
}