Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for a distributed parallel processing database system that persists table data in memory to a distributed file system. A distributed parallel processing database system persists table data in memory to a distributed file system. A parameter of creating a database table specifies that data records in the database table and history of changes to the data records can be stored in memory as well as in the distributed file system. When the database table is populated or otherwise modified, data records and the history in memory are evicted to the distributed file system as log files and removed from memory. The log files can be designated as write-only, where the data records, once written, cannot be read by structured query language (SQL) queries, or as read-write, where the data records, once written, can be read by SQL queries.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for distributed data management. One of the methods includes maintaining, by a first member in a distributed data management system having multiple computing members installed on multiple respective computers, a first garbage collection version vector that includes, for each member in the distributed data management system, a garbage collection version that represents a number of garbage collection processes performed by the member on a respective copy of a replicated data region maintained by the member in the data management system. If the first garbage collection version vector is different than a second garbage collection version vector received from a different provider member, a first replication process is performed that is different than a second replication process that is performed when the first garbage collection version vector matches the second garbage collection version vector.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for distributed data management. One of the methods includes maintaining, by a first member in a distributed data management system having multiple computing members installed on multiple respective computers, a first garbage collection version vector that includes, for each member in the distributed data management system, a garbage collection version that represents a number of garbage collection processes performed by the member on a respective copy of a replicated data region maintained by the member in the data management system. If the first garbage collection version vector is different than a second garbage collection version vector received from a different provider member, a first replication process is performed that is different than a second replication process that is performed when the first garbage collection version vector matches the second garbage collection version vector.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for a distributed parallel processing database system that persists table data in memory to a distributed file system. A distributed parallel processing database system persists table data in memory to a distributed file system. A parameter of creating a database table specifies that data records in the database table and history of changes to the data records can be stored in memory as well as in the distributed file system. When the database table is populated or otherwise modified, data records and the history in memory are evicted to the distributed file system as log files and removed from memory. The log files can be designated as write-only, where the data records, once written, cannot be read by structured query language (SQL) queries, or as read-write, where the data records, once written, can be read by SQL queries.