bharatviswa504 commented on a change in pull request #798: HDDS-1499. OzoneManager Cache. URL: https://github.com/apache/hadoop/pull/798#discussion_r284361801
########## File path: hadoop-hdds/common/src/main/java/org/apache/hadoop/utils/db/TypedTable.java ########## @@ -69,8 +94,40 @@ public boolean isEmpty() throws IOException { return rawTable.isEmpty(); } + /** + * Returns the value mapped to the given key in byte array or returns null + * if the key is not found. + * + * First it will check from cache, if it has entry return the value + * otherwise, get from the RocksDB table. + * + * @param key metadata key + * @return VALUE + * @throws IOException + */ @Override public VALUE get(KEY key) throws IOException { + // Here the metadata lock will guarantee that cache is not updated for same + // key during get key. + if (cache != null) { + CacheValue<VALUE> cacheValue = cache.get(new CacheKey<>(key)); + if (cacheValue == null) { + return getFromTable(key); + } else { + // Doing this because, if the Cache Value Last operation is deleted + // means it will eventually removed from DB. So, we should return null. + if (cacheValue.getLastOperation() != CacheValue.OperationType.DELETED) { + return cacheValue.getValue(); + } else { + return null; Review comment: Yes, we can pass null value to CacheValue actual value. This will work. Done. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org