public List<SegmentHeader> getSegmentHeaders() {
// Special case 0 and 1 workers, for which the 'union' operation
// is trivial.
switch (workers.size()) {
case 0:
return Collections.emptyList();
case 1:
return workers.get(0).getSegmentHeaders();
default:
final List<SegmentHeader> list = new ArrayList<SegmentHeader>();
final Set<SegmentHeader> set = new HashSet<SegmentHeader>();
for (SegmentCacheWorker worker : workers) {
for (SegmentHeader header : worker.getSegmentHeaders()) {
if (set.add(header)) {
list.add(header);
}
}
}
return list;
}
}
public FlushResult call() throws Exception {
// For each measure and each star, ask the index
// which headers intersect.
final List<SegmentHeader> headers = new ArrayList<SegmentHeader>();
final List<Member> measures = CacheControlImpl.findMeasures(region);
final SegmentColumn[] flushRegion = CacheControlImpl.findAxisValues(region);
final List<RolapStar> starList = CacheControlImpl.getStarList(region);
for (Member member : measures) {
if (!(member instanceof RolapStoredMeasure)) {
continue;
}
final RolapStoredMeasure storedMeasure = (RolapStoredMeasure) member;
final RolapStar star = storedMeasure.getCube().getStar();
final SegmentCacheIndex index = cacheMgr.indexRegistry.getIndex(star);
headers.addAll(
index.intersectRegion(
member.getDimension().getSchema().getName(),
((RolapSchema) member.getDimension().getSchema()).getChecksum(),
storedMeasure.getCube().getName(),
storedMeasure.getName(),
storedMeasure.getCube().getStar().getFactTable().getAlias(),
flushRegion));
}
// If flushRegion is empty, this means we must clear all
// segments for the region's measures.
if (flushRegion.length == 0) {
for (final SegmentHeader header : headers) {
for (RolapStar star : starList) {
cacheMgr.indexRegistry.getIndex(star).remove(header);
}
// Remove the segment from external caches. Use an
// executor, because it may take some time. We discard
// the future, because we don't care too much if it fails.
cacheControlImpl.trace(
"discard segment - it cannot be constrained and maintain consistency:\n"
+ header.getDescription());
final Future<?> task =
cacheMgr.cacheExecutor.submit(
new Runnable() {
public void run() {
try {
// Note that the SegmentCache API doesn't
// require us to verify that the segment
// exists (by calling "contains") before we
// call "remove".
cacheMgr.compositeCache.remove(header);
} catch (Throwable e) {
LOGGER.warn("remove header failed: " + header, e);
}
}
});
Util.safeGet(task, "SegmentCacheManager.flush");
}
return new FlushResult(Collections.<Callable<Boolean>>emptyList());
}
// Now we know which headers intersect. For each of them,
// we append an excluded region.
//
// TODO: Optimize the logic here. If a segment is mostly
// empty, we should trash it completely.
final List<Callable<Boolean>> callableList = new ArrayList<Callable<Boolean>>();
for (final SegmentHeader header : headers) {
if (!header.canConstrain(flushRegion)) {
// We have to delete that segment altogether.
cacheControlImpl.trace(
"discard segment - it cannot be constrained and maintain consistency:\n"
+ header.getDescription());
for (RolapStar star : starList) {
cacheMgr.indexRegistry.getIndex(star).remove(header);
}
continue;
}
final SegmentHeader newHeader = header.constrain(flushRegion);
for (final SegmentCacheWorker worker : cacheMgr.segmentCacheWorkers) {
callableList.add(
new Callable<Boolean>() {
public Boolean call() throws Exception {
boolean existed;
if (worker.supportsRichIndex()) {
final SegmentBody sb = worker.get(header);
existed = worker.remove(header);
if (sb != null) {
worker.put(newHeader, sb);
}
} else {
// The cache doesn't support rich index. We
// have to clear the segment entirely.
existed = worker.remove(header);
}
return existed;
}
});
}
for (RolapStar star : starList) {
SegmentCacheIndex index = cacheMgr.indexRegistry.getIndex(star);
index.remove(header);
index.add(newHeader, false, null);
}
}
// Done
return new FlushResult(callableList);
}