> What is the cardinality like on these indexes? Can you provide the > schema creation for these two column families?
This is the schema of the CFs: create column family CF_users with comparator = UTF8Type and column_metadata = [ {column_name: userSBCode, validation_class: UTF8Type, index_type: KEYS}, {column_name: userEmail, validation_class: UTF8Type, index_type: KEYS}, {column_name: userName, validation_class: UTF8Type}, {column_name: userLastName, validation_class: UTF8Type}, {column_name: userOwnPhoneKey, validation_class: UTF8Type, index_type: KEYS}, {column_name: userOwnPhone, validation_class: UTF8Type, index_type: KEYS}, {column_name: userPasswordMD5, validation_class: UTF8Type}, {column_name: userDOB, validation_class: UTF8Type}, {column_name: userGender, validation_class: UTF8Type}, {column_name: userProfilePicMD5, validation_class: UTF8Type}, {column_name: userAbout, validation_class: UTF8Type}, {column_name: userLastSession, validation_class: UTF8Type} {column_name: userMasterKey, validation_class: UTF8Type} ]; create column family CF_SBMessages with comparator = UTF8Type and column_metadata = [ {column_name: SBMessageId, validation_class: UTF8Type, index_type: KEYS}, {column_name: fromSBCode, validation_class: UTF8Type, index_type: KEYS}, {column_name: SBMessageDate, validation_class: UTF8Type, index_type: KEYS}, {column_name: SBMessageType, validation_class: UTF8Type}, {column_name: SBMessageText, validation_class: UTF8Type}, {column_name: SBMessageAttachments, validation_class: UTF8Type}, ]; I've read about the importance of keeping the cardinality of the secondary indexes low (great article at http://pkghosh.wordpress.com/2011/03/02/cassandra-secondary-index-patterns/), and I'm afraid that we did completely the opposite (we did consider the secondary indexes as alternate indexes). I guess here is some work to do to create other CFs to store these secondary indexes. Anyway, I still don't understand why did appear these peaks (by the way, last night there wasn't any)