Abstract: An example method of live migration of distributed databases may include implementing a first database access mode with respect to a distributed database to be migrated from an original set of storage servers to a destination set of storage servers, wherein, in the first database access mode, database read requests are routed to the original set of storage servers and database update requests are routed to both the original set of storage servers and the destination set of storage servers. The method may further include copying a plurality of records of the distributed database from the original set of storage servers to the destination set of storage servers. The method may further include switching to a second database access mode, in which database read requests are routed to the destination set of storage servers and database update requests are routed to both the original set of storage servers and the destination set of storage servers.

Abstract: An example distributed database includes a first instance and a second instance. The first instance is configured to: responsive to performing, within a scope of a database update transaction, a first database update operation, invalidate a cache entry residing in the first database cache maintained by the first instance, wherein the first database update operation is reflected by a transaction log maintained by the first instance; perform, within the scope of the database update transaction, a second database update operation to insert an identifier of the cache entry into a predetermined table of the distributed database, wherein the second database update operation is reflected by the transaction log; and responsive to committing the database update transaction, transmit the transaction log to the second instance.

Abstract: An example distributed database includes a first instance and a second instance. The first instance is configured to: responsive to performing, within a scope of a database update transaction, a first database update operation, invalidate a cache entry residing in the first database cache maintained by the first instance, wherein the first database update operation is reflected by a transaction log maintained by the first instance; perform, within the scope of the database update transaction, a second database update operation to insert an identifier of the cache entry into a predetermined table of the distributed database, wherein the second database update operation is reflected by the transaction log; and responsive to committing the database update transaction, transmit the transaction log to the second instance.

Abstract: An example method of live migration of distributed databases may include implementing a first database access mode with respect to a distributed database to be migrated from an original set of storage servers to a destination set of storage servers, wherein, in the first database access mode, database read requests are routed to the original set of storage servers and database update requests are routed to both the original set of storage servers and the destination set of storage servers. The method may further include copying a plurality of records of the distributed database from the original set of storage servers to the destination set of storage servers. The method may further include switching to a second database access mode, in which database read requests are routed to the destination set of storage servers and database update requests are routed to both the original set of storage servers and the destination set of storage servers.

Abstract: An example method of live migration of distributed databases may include implementing a first intermediate database access mode with respect to a distributed database to be migrated from an original set of storage servers to a destination set of storage servers, wherein, in the first database access mode, database read requests are routed to the original set of storage servers and database update requests are routed to both the original set of storage servers and the destination set of storage servers. The method may further include copying a plurality of records of the distributed database from the original set of storage servers to the destination set of storage servers. The method may further include switching to a second intermediate database access mode, in which database read requests are routed to the destination set of storage servers and database update requests are routed to both the original set of storage servers and the destination set of storage servers.

Abstract: This disclosure is directed to bidirectional replication of data across two or more data centers where each data center has datastores corresponding to other data centers. When new data is written or updated at a particular data center, that new data may be updated on datastores corresponding to that particular data center at the other data centers. A data center system at the particular data center may indicate to other data center systems at the other data centers that data has been updated along with providing an identity of the particular data center. The other data center systems may update the datastores corresponding with the particular data center with the new data. When data is accessed at a data center, a key indicating the data center of origin may be used to determine the datastore from among a plurality of datastores at a data center in which data is stored.

Abstract: An example method of live migration of distributed databases may include implementing a first intermediate database access mode with respect to a distributed database to be migrated from an original set of storage servers to a destination set of storage servers, wherein, in the first database access mode, database read requests are routed to the original set of storage servers and database update requests are routed to both the original set of storage servers and the destination set of storage servers. The method may further include copying a plurality of records of the distributed database from the original set of storage servers to the destination set of storage servers. The method may further include switching to a second intermediate database access mode, in which database read requests are routed to the destination set of storage servers and database update requests are routed to both the original set of storage servers and the destination set of storage servers.