Cassandra with Hadoop - 1

Cassandra creates a ___________ for each table, which allows you to symlink a table to a chosen physical drive or data volume. a) directory b) subdirectory c) domain d) path

b) subdirectory The new file name format includes the keyspace name to distinguish which keyspace and table the file contains when streaming or bulk loading data

A _________ grants initial permissions, and subsequently a user may or may not be given the permission to grant/revoke permissions. a) keyspace b) superuser c) sudouser d) none of the mentioned

b) superuser Object permission management is based on internal authorization

Point out the correct statement : a) Cassandra accommodates expensive, consumer SSDs extremely well b) Cassandra re-writes or re-reads existing data, and never overwrites the rows in place c) Cassandra uses a storage structure similar to a Log-Structured Merge Tree d) None of the mentioned

c) Cassandra uses a storage structure similar to a Log-Structured Merge Tree A log-structured engine that avoids overwrites and uses sequential IO to update data is essential for writing to hard disks (HDD) and solid-state disks (SSD).

Cassandra marks data to be deleted using: a) tombstone b) combstone c) tenstone d) none of the mentioned

a) tombstone Cassandra also does not delete in place because the SSTable is immutable

__________ is one of many possible IAuthorizer implementations, and the one that stores permissions in the system_auth.permissions table to support all authorization-related CQL statements. a) CassandraAuth b) CassandraAuthorizer c) CassAuthorizer d) All of the mentioned

b) CassandraAuthorizer Configuration consists mainly of changing the authorizer option in the cassandra.yaml to use the CassandraAuthorizer.

Data in the commit log is purged after its corresponding data in the memtable is flushed to an _________. a) SSHables b) SSTable c) Memtables d) None of the mentioned

b) SSTable SSTables are immutable, not written to again after the memtable is flushed.

Point out the wrong statement: a) Cassandra provides fine-grained control of table storage on disk, writing tables to disk using separate table directories within each keyspace directory b) The hinted handoff feature and Cassandra conformance and conformance to the ACID c) Client utilities and application programming interfaces (APIs) for developing applications for data storage and retrieval are available d) None of the mentioned

b) The hinted handoff feature and Cassandra conformance and conformance to the ACID The hinted handoff feature and Cassandra conformance and non-conformance to the ACID.

When ___________ contents exceed a configurable threshold, the memtable data, which includes indexes, is put in a queue to be flushed to disk a) subtable b) memtable c) intable d) memorytable

b) memtable You can configure the length of the queue by changing memtable_flush_queue_size in the cassandra.yaml.

For each SSTable, Cassandra creates _________ index. a) memory b) partition c) in memory d) all of the mentioned

b) partition Partition index is list of partition keys and the start position of rows in the data file (on disk).

Tombstones exist for a configured time period defined by the _______ value set on the table. a) gc_grace_minutes b) gc_grace_time c) gc_grace_seconds d) gc_grace_hours

c) gc_grace_seconds During compaction, there is a temporary spike in disk space usage and disk I/O because the old and new SSTables co-exist