/**
* Returns the time when the index segment with the given <code>indexName</code> was in use for
* the last time. The returned time does not accurately say until when an index segment was in
* use, but it does guarantee that the index segment in question was not in use anymore at the
* returned time.
*
* <p>There are two special cases of return values:
*
* <ul>
* <li>{@link Long#MAX_VALUE}: indicates that the index segment is still in active use.
* <li>{@link Long#MIN_VALUE}: indicates that there is no index segment with the given name.
* </ul>
*
* @param indexName name of an index segment.
* @return the time when the index segment with the given name was in use the last time.
*/
long getLastUseOf(String indexName) {
Long previous = null;
for (Map.Entry<Long, IndexInfos> entry : indexInfosMap.entrySet()) {
IndexInfos infos = entry.getValue();
if (infos.contains(indexName)) {
if (previous == null) {
// still in use
return Long.MAX_VALUE;
} else {
return previous;
}
}
previous = infos.getLastModified();
}
return Long.MIN_VALUE;
}
/**
* Adds an index infos to the history. This method will not modify nor keep a reference to the
* passed <code>infos</code>.
*
* @param infos the index infos to add.
*/
void addIndexInfos(IndexInfos infos) {
// must clone infos because it is modifiable
indexInfosMap.put(infos.getGeneration(), infos.clone());
}
/** Removes index infos older than {@link #maxAge} from this history. */
void pruneOutdated() {
long threshold = System.currentTimeMillis() - maxAge;
log.debug("Pruning index infos older than: " + threshold + "(" + indexDir + ")");
Iterator<IndexInfos> it = indexInfosMap.values().iterator();
// never prune the current generation
if (it.hasNext()) {
IndexInfos infos = it.next();
log.debug("Skipping first index infos. generation=" + infos.getGeneration());
}
while (it.hasNext()) {
IndexInfos infos = (IndexInfos) it.next();
if (infos.getLastModified() < threshold) {
// check associated redo log
try {
String logName = getRedoLogName(infos.getGeneration());
if (indexDir.fileExists(logName)) {
long lastModified = indexDir.fileModified(logName);
if (lastModified > threshold) {
log.debug(
"Keeping redo log with generation={}, timestamp={}",
infos.getGeneration(),
lastModified);
continue;
}
// try do delete it
try {
indexDir.deleteFile(logName);
log.debug(
"Deleted redo log with generation={}, timestamp={}",
infos.getGeneration(),
lastModified);
} catch (IOException e) {
log.warn("Unable to delete: " + indexDir + "/" + logName);
continue;
}
}
// delete index infos
try {
indexDir.deleteFile(infos.getFileName());
log.debug("Deleted index infos with generation={}", infos.getGeneration());
it.remove();
} catch (IOException e) {
log.warn("Unable to delete: " + indexDir + "/" + infos.getFileName());
}
} catch (IOException e) {
log.warn("Failed to check if {} is outdated: {}", infos.getFileName(), e);
}
}
}
}
