* Add a task to execute "SHOW COMPACTIONS"
* @param ast The parsed command tree.
* @throws SemanticException Parsing failed.
*/
private void analyzeShowCompactions(ASTNode ast) throws SemanticException {
ShowCompactionsDesc desc = new ShowCompactionsDesc(ctx.getResFile());
rootTasks.add(TaskFactory.get(new DDLWork(getInputs(), getOutputs(), desc), conf));
setFetchTask(createFetchTask(desc.getSchema()));
}