Abstract: During a storage technique, multiple messages (such as emails) associated with a user of a communication application are received. Then, the multiple messages are stored in a message table associated with the user and the multiple messages are indexed in an index associated with the user. This index may be divided into multiple divisions if a total number of messages stored in the message table exceeds a threshold value, where each division corresponds to messages received during a different time interval.

Abstract: A system, methods, and apparatus are provided for ensuring consistency of derived data, relative to primary data, in a distributed data storage system. Primary data and derived data are stored on and/or managed by separate components of the data storage system, such as different storage engines. Primary data are written and updated as specified in write requests, which may be queries directed at the primary storage engine. Results of primary data writes are delivered directly to the derived storage engine. If an update to derived data fails, a record is made; if the update succeeds, any recorded failed writes to the same data are cleared. The derived storage engine also receives write results via a change capture stream of events affecting the primary data, and can use these copies of write results to fix failed updates and to clear failures from the failed write records.

Abstract: During a search technique, indexes associated with user accounts of users that are using the communication application are opened in memory from a transactional key-value database. These indexes encompass messages (such as emails) communicated using the communication application, and each of the users has at least one separate, associated index. When a search query associated with a target user account is received from the communication application, a search based on the search query is performed by reading the associated index in the memory from the transactional key-value database without managing the index using a file system. Then, a result for the search query is returned.

Abstract: During a storage technique, multiple messages (such as emails) associated with a user of a communication application are received. Then, the multiple messages are stored in a message table associated with the user and the multiple messages are indexed in an index associated with the user. This index may be divided into multiple divisions if a total number of messages stored in the message table exceeds a threshold value, where each division corresponds to messages received during a different time interval.