/** Validates the properties of the chosen cache pool. Throws on error. */
public static void validateCachePool(
THdfsCachingOp op, Long directiveId, TableName table, HdfsPartition partition)
throws ImpalaRuntimeException {
CacheDirectiveEntry entry = getDirective(directiveId);
Preconditions.checkNotNull(entry);
if (!op.getCache_pool_name().equals(entry.getInfo().getPool())) {
throw new ImpalaRuntimeException(
String.format(
"Cannot cache partition in "
+ "pool '%s' because it is already cached in '%s'. To change the cache "
+ "pool for this partition, first uncache using: ALTER TABLE %s.%s "
+ "%sSET UNCACHED",
op.getCache_pool_name(),
entry.getInfo().getPool(),
table.getDb(),
table,
// Insert partition string if partition non null
partition != null
? String.format(
" PARTITION(%s) ", partition.getPartitionName().replaceAll("/", ", "))
: ""));
}
}
/**
* Returns a boolean indicating if the given thrift caching operation would perform an update on
* an already existing cache directive.
*/
public static boolean isUpdateOp(THdfsCachingOp op, Map<String, String> params)
throws ImpalaRuntimeException {
Long directiveId = Long.parseLong(params.get(CACHE_DIR_ID_PROP_NAME));
CacheDirectiveEntry entry = getDirective(directiveId);
Preconditions.checkNotNull(entry);
// Verify cache pool
if (!op.getCache_pool_name().equals(entry.getInfo().getPool())) {
return false;
}
// Check cache replication factor
if ((op.isSetReplication() && op.getReplication() != entry.getInfo().getReplication())
|| (!op.isSetReplication()
&& entry.getInfo().getReplication()
!= JniCatalogConstants.HDFS_DEFAULT_CACHE_REPLICATION_FACTOR)) {
return true;
}
return false;
}
/**
* Validates and returns true if a parameter map contains a cache directive ID and validates it
* against the NameNode to make sure it exists. If the cache directive ID does not exist, we
* remove the value from the parameter map, issue a log message and return false. As the value is
* not written back to the Hive MS from this method, the result will be only valid until the next
* metadata fetch. Lastly, we update the cache replication factor in the parameters with the value
* read from HDFS.
*/
public static boolean validateCacheParams(Map<String, String> params) {
Long directiveId = getCacheDirectiveId(params);
if (directiveId == null) return false;
CacheDirectiveEntry entry = null;
try {
entry = getDirective(directiveId);
} catch (ImpalaRuntimeException e) {
if (e.getCause() != null && e.getCause() instanceof RemoteException) {
// This exception signals that the cache directive no longer exists.
LOG.error("Cache directive does not exist", e);
params.remove(CACHE_DIR_ID_PROP_NAME);
params.remove(CACHE_DIR_REPLICATION_PROP_NAME);
} else {
// This exception signals that there was a connection problem with HDFS.
LOG.error("IO Exception, possible connectivity issues with HDFS", e);
}
return false;
}
Preconditions.checkNotNull(entry);
// On the upgrade path the property might not exist, if it exists
// and is different from the one from the meta store, issue a warning.
String replicationFactor = params.get(CACHE_DIR_REPLICATION_PROP_NAME);
if (replicationFactor != null
&& Short.parseShort(replicationFactor) != entry.getInfo().getReplication()) {
LOG.info(
"Replication factor for entry in HDFS differs from value in Hive MS: "
+ entry.getInfo().getPath().toString()
+ " "
+ entry.getInfo().getReplication().toString()
+ " != "
+ params.get(CACHE_DIR_REPLICATION_PROP_NAME));
}
params.put(CACHE_DIR_REPLICATION_PROP_NAME, String.valueOf(entry.getInfo().getReplication()));
return true;
}
/**
* Waits on a cache directive to either complete or stop making progress. Progress is checked by
* polling the HDFS caching stats every DFS_NAMENODE_PATH_BASED_CACHE_REFRESH_INTERVAL_MS. We
* verify the request's "currentBytesCached" is increasing compared to "bytesNeeded". If
* "currentBytesCached" == "bytesNeeded" or if no progress is made for a
* MAX_UNCHANGED_CACHING_REFRESH_INTERVALS, this function returns.
*/
public static void waitForDirective(long directiveId) throws ImpalaRuntimeException {
long bytesNeeded = 0L;
long currentBytesCached = 0L;
CacheDirectiveEntry cacheDir = getDirective(directiveId);
if (cacheDir == null) return;
bytesNeeded = cacheDir.getStats().getBytesNeeded();
currentBytesCached = cacheDir.getStats().getBytesCached();
LOG.debug(
String.format(
"Waiting on cache directive id: %d. Bytes " + "cached (%d) / needed (%d)",
directiveId, currentBytesCached, bytesNeeded));
// All the bytes are cached, just return.
if (bytesNeeded == currentBytesCached) return;
// The refresh interval is how often HDFS will update cache directive stats. We use
// this value to determine how frequently we should poll for changes.
long hdfsRefreshIntervalMs =
FileSystemUtil.getConfiguration()
.getLong(
DFSConfigKeys.DFS_NAMENODE_PATH_BASED_CACHE_REFRESH_INTERVAL_MS,
DFSConfigKeys.DFS_NAMENODE_PATH_BASED_CACHE_REFRESH_INTERVAL_MS_DEFAULT);
Preconditions.checkState(hdfsRefreshIntervalMs > 0);
// Loop until either MAX_UNCHANGED_CACHING_REFRESH_INTERVALS have passed with no
// changes or all required data is cached.
int unchangedCounter = 0;
while (unchangedCounter < MAX_UNCHANGED_CACHING_REFRESH_INTERVALS) {
long previousBytesCached = currentBytesCached;
cacheDir = getDirective(directiveId);
if (cacheDir == null) return;
currentBytesCached = cacheDir.getStats().getBytesCached();
bytesNeeded = cacheDir.getStats().getBytesNeeded();
if (currentBytesCached == bytesNeeded) {
LOG.debug(
String.format(
"Cache directive id: %d has completed." + "Bytes cached (%d) / needed (%d)",
directiveId, currentBytesCached, bytesNeeded));
return;
}
if (currentBytesCached == previousBytesCached) {
++unchangedCounter;
} else {
unchangedCounter = 0;
}
try {
// Sleep for the refresh interval + a little bit more to ensure a full interval
// has completed. A value of 25% the refresh interval was arbitrarily chosen.
Thread.sleep((long) (hdfsRefreshIntervalMs * 1.25));
} catch (InterruptedException e) {
/* ignore */
}
}
LOG.warn(
String.format(
"No changes in cached bytes in: %d(ms). All data may not "
+ "be cached. Final stats for cache directive id: %d. Bytes cached (%d)/needed "
+ "(%d)",
hdfsRefreshIntervalMs * MAX_UNCHANGED_CACHING_REFRESH_INTERVALS,
directiveId,
currentBytesCached,
bytesNeeded));
}
/**
* Given a cache directive ID, returns the replication factor for the directive. Returns null if
* no outstanding cache directives match this ID.
*/
public static Short getCacheReplication(long directiveId) throws ImpalaRuntimeException {
CacheDirectiveEntry entry = getDirective(directiveId);
return entry != null ? entry.getInfo().getReplication() : null;
}
/**
* Given a cache directive ID, returns the pool the directive is cached in. Returns null if no
* outstanding cache directive match this ID.
*/
public static String getCachePool(long directiveId) throws ImpalaRuntimeException {
CacheDirectiveEntry entry = getDirective(directiveId);
return entry == null ? null : entry.getInfo().getPool();
}
