... external write ahead logs are available Therefore, although some cloud storage systems, such as HBase [1] and Cassandra [16], have adopted LSM-trees for maintaining their data, instead of performing ... monitoring the status of other tablet servers in the cluster, and provides the interface for users to update the metadata of the database such as create a new table and add column groups into a table ... database systems such as System R [14] use shadow paging strategy to avoid the cost of in- place updates When a transaction updates a data page, it makes a copy, i.e., a shadow, of that page and...