Adaptive query routing in a replicated database environment

A computer system comprising a database client comprising a processing unit and memory that accesses a replicated database system, the replicated database system comprising at least one source node and at least one replica node, the database client configured to perform a prepared statement execution method, the method comprising:

• sending a request to a database system node to prepare a statement;
• receiving a prepared statement from the database system node, the prepared statement specifying at least one database system node on which the prepared statement is executable;
• sending the prepared statement to the at least one node specified in the prepared statement;
• and
• receiving an updated prepared statement, the updated prepared statement specifying one or more nodes on which the updated prepared statement is executable, the one or more nodes comprising a node that was not the at least one node specified in the prepared statement, or omitting the at least one node specified in the prepared statement.

One or more tangible computer-readable storage media storing computer-executable instructions for causing a computer device operating a first database system node, the computer device comprising a processing unit and memory and storing at least one database table and in communication with a database client and at least second and third database system nodes, programmed thereby to perform a method for facilitating prepared statement execution in a replicated database environment, the method comprising:

• determining that an availability status of a replica node of the replicated database environment has changed;
• recording the availability status change in a data store comprising availability status information for nodes of the replicated database system;
• incrementing a metadata identifier;
• receiving a prepared statement from the database client, the prepared statement associated with a version timestamp;
• comparing the incremented metadata identifier with the version timestamp;
• determining that the prepared statement should be updated;
• updating the prepared statement using the availability status information of the data store;
• and
• sending the updated prepared statement to the database client.