public long freeMemory() {
long memoryFreed = 0;
for (MemoryBlock block : allocatedPages) {
memoryManager.freePage(block);
shuffleMemoryManager.release(block.size());
memoryFreed += block.size();
}
allocatedPages.clear();
currentPage = null;
currentPagePosition = -1;
freeSpaceInCurrentPage = 0;
return memoryFreed;
}
/**
* Allocates more memory in order to insert an additional record. This will request additional
* memory from the {@link ShuffleMemoryManager} and spill if the requested memory can not be
* obtained.
*
* @param requiredSpace the required space in the data page, in bytes, including space for storing
* the record size.
*/
private void allocateSpaceForRecord(int requiredSpace) throws IOException {
// TODO: merge these steps to first calculate total memory requirements for this insert,
// then try to acquire; no point in acquiring sort buffer only to spill due to no space in the
// data page.
if (!sorter.hasSpaceForAnotherRecord()) {
logger.debug("Attempting to expand sort pointer array");
final long oldPointerArrayMemoryUsage = sorter.getMemoryUsage();
final long memoryToGrowPointerArray = oldPointerArrayMemoryUsage * 2;
final long memoryAcquired = shuffleMemoryManager.tryToAcquire(memoryToGrowPointerArray);
if (memoryAcquired < memoryToGrowPointerArray) {
shuffleMemoryManager.release(memoryAcquired);
spill();
} else {
sorter.expandPointerArray();
shuffleMemoryManager.release(oldPointerArrayMemoryUsage);
}
}
if (requiredSpace > freeSpaceInCurrentPage) {
logger.trace(
"Required space {} is less than free space in current page ({})",
requiredSpace,
freeSpaceInCurrentPage);
// TODO: we should track metrics on the amount of space wasted when we roll over to a new page
// without using the free space at the end of the current page. We should also do this for
// BytesToBytesMap.
if (requiredSpace > PAGE_SIZE) {
throw new IOException(
"Required space " + requiredSpace + " is greater than page size (" + PAGE_SIZE + ")");
} else {
final long memoryAcquired = shuffleMemoryManager.tryToAcquire(PAGE_SIZE);
if (memoryAcquired < PAGE_SIZE) {
shuffleMemoryManager.release(memoryAcquired);
spill();
final long memoryAcquiredAfterSpilling = shuffleMemoryManager.tryToAcquire(PAGE_SIZE);
if (memoryAcquiredAfterSpilling != PAGE_SIZE) {
shuffleMemoryManager.release(memoryAcquiredAfterSpilling);
throw new IOException("Unable to acquire " + PAGE_SIZE + " bytes of memory");
}
}
currentPage = memoryManager.allocatePage(PAGE_SIZE);
currentPagePosition = currentPage.getBaseOffset();
freeSpaceInCurrentPage = PAGE_SIZE;
allocatedPages.add(currentPage);
}
}
}
/** Write a record to the sorter. */
public void insertRecord(
Object recordBaseObject, long recordBaseOffset, int lengthInBytes, long prefix)
throws IOException {
// Need 4 bytes to store the record length.
final int totalSpaceRequired = lengthInBytes + 4;
if (!haveSpaceForRecord(totalSpaceRequired)) {
allocateSpaceForRecord(totalSpaceRequired);
}
final long recordAddress =
memoryManager.encodePageNumberAndOffset(currentPage, currentPagePosition);
final Object dataPageBaseObject = currentPage.getBaseObject();
PlatformDependent.UNSAFE.putInt(dataPageBaseObject, currentPagePosition, lengthInBytes);
currentPagePosition += 4;
PlatformDependent.copyMemory(
recordBaseObject, recordBaseOffset, dataPageBaseObject, currentPagePosition, lengthInBytes);
currentPagePosition += lengthInBytes;
freeSpaceInCurrentPage -= totalSpaceRequired;
sorter.insertRecord(recordAddress, prefix);
}