public void open() throws DbException, TransactionAbortedException {
// some code goes here
if (i_pos != null) {
i = i_pos;
} else {
Catalog gc = Database.getCatalog();
HeapFile file = (HeapFile) gc.getDbFile(tableid);
i = file.iterator(tid);
}
i.open();
}
/**
* Retrieve the specified page with the associated permissions. Will acquire a lock and may block
* if that lock is held by another transaction.
*
* <p>The retrieved page should be looked up in the buffer pool. If it is present, it should be
* returned. If it is not present, it should be added to the buffer pool and returned. If there is
* insufficient space in the buffer pool, an page should be evicted and the new page should be
* added in its place.
*
* @param tid the ID of the transaction requesting the page
* @param pid the ID of the requested page
* @param perm the requested permissions on the page
* @throws DbException
* @throws TransactionAbortedException
*/
public Page getPage(TransactionId tid, PageId pid, Permissions perm)
throws DbException, TransactionAbortedException {
lockManager.acquireLock(tid, pid, perm);
if (pageIdToPages.containsKey(pid)) {
return pageIdToPages.get(pid);
}
if (currentPages.get() == maxPages) {
evictPage();
}
int tableId = pid.getTableId();
Catalog catalog = Database.getCatalog();
DbFile dbFile = catalog.getDatabaseFile(tableId);
Page page = dbFile.readPage(pid);
pageIdToPages.put(pid, page);
currentPages.incrementAndGet();
return page;
}
private void createAliasedTd() {
Catalog gc = Database.getCatalog();
TupleDesc old_td = gc.getTupleDesc(tableid);
String[] newFieldAr = new String[old_td.numFields()];
Type[] typeAr = new Type[old_td.numFields()];
String field = null;
for (int i = 0; i < newFieldAr.length; i++) {
field = old_td.getFieldName(i);
if (alias == null) {
alias = "null";
} else if (field == null) {
field = "null";
}
newFieldAr[i] = alias + "." + field;
typeAr[i] = old_td.getFieldType(i);
}
td = new TupleDesc(typeAr, newFieldAr);
}
public static void main(String[] args) throws Exception {
if (args.length < 1 || args.length > 5) {
System.out.println("Invalid number of arguments.\n" + usage);
return;
}
String confDir = Server.DEFAULT_CONF_DIR;
String outputDir = DEFAULT_OUTPUT_DIR;
if (args.length >= 3 && args[1].equals("--conf")) {
confDir = args[2];
args = ParallelUtility.removeArg(args, 1);
args = ParallelUtility.removeArg(args, 1);
}
if (args.length >= 3 && args[1].equals("--output")) {
outputDir = args[2];
args = ParallelUtility.removeArg(args, 1);
args = ParallelUtility.removeArg(args, 1);
}
Catalog c = Database.getCatalog();
SocketInfo[] workers = ParallelUtility.loadWorkers(confDir);
c.loadSchema(args[0]);
TableStats.computeStatistics();
File catalogFile = new File(args[0]);
for (SocketInfo worker : workers) {
File folder = new File(outputDir + "/" + worker.getHost() + "_" + worker.getPort());
folder.mkdirs();
ParallelUtility.copyFileFolder(
catalogFile, new File(folder.getAbsolutePath() + "/catalog.schema"), true);
}
TransactionId fateTid = new TransactionId();
Iterator<Integer> tableIds = c.tableIdIterator();
while (tableIds.hasNext()) {
int tableid = tableIds.next();
int numTuples = getTotalTuples(tableid);
HeapFile h = (HeapFile) c.getDatabaseFile(tableid);
int eachSplitSize = numTuples / workers.length;
int[] splitSizes = new int[workers.length];
Arrays.fill(splitSizes, eachSplitSize);
for (int i = 0; i < numTuples % workers.length; i++) {
splitSizes[i] += 1;
}
DbFileIterator dfi = h.iterator(fateTid);
dfi.open();
for (int i = 0; i < workers.length; i++) {
ArrayList<Tuple> buffer = new ArrayList<Tuple>();
for (int j = 0; j < splitSizes[i]; j++) {
dfi.hasNext();
buffer.add(dfi.next());
}
Iterator<TDItem> items = h.getTupleDesc().iterator();
ArrayList<Type> types = new ArrayList<Type>();
while (items.hasNext()) types.add(items.next().fieldType);
writeHeapFile(
buffer,
new File(
outputDir
+ "/"
+ workers[i].getHost()
+ "_"
+ workers[i].getPort()
+ "/"
+ c.getTableName(tableid)
+ ".dat"),
BufferPool.getPageSize(),
types.toArray(new Type[] {}));
}
}
}
