Oracle International Corporation

Shih-Yu Huang

Wei Zhang

Yunrui Li

Kothanda Umamageswaran

Jia Shi

Graham Ivey

Shampa Chakravarty

Vijayakrishnan Nagarajan

The present disclosure relates to adaptively overlapping redo writes. A log writer, while operating in a thin mode, may assign a first log writer group of a plurality of log writer groups to write one or more first redo log records to an online redo log in response to determining that a pipelining parameter is satisfied. The thin mode may be associated with one or more target sizes that are less than one or more target sizes associated with a thick mode. The log writer may determine to operate the thick mode based at least in part on at least a portion of the plurality of log writer groups being unavailable to write one or more second redo log records to the online redo log. The log writer, while operating in the thick mode, may assign a second log writer group of the plurality of log writer groups to write one or more second redo log records from the log buffer to the online redo log in response to determining that an amount of redo log records in the log buffer meets one of the one or more target sizes associated with the thick mode. The log writer, while operating in the thick mode, may assign a third log writer group of the plurality of log writer groups to write one or more second redo log records from the log buffer to the online redo log in response to determining that a highest busy group number meets or exceeds a core threshold.

Adaptively overlapping the writing of redo log records

Techniques related to failover to the secondary storage server from a primary storage server of a database server without degrading the performance of servicing storage requests for client applications are provided. In an embodiment, the secondary storage server receives, from the database server, an eviction notification indicating that a set of data blocks has been evicted from a cache. The secondary storage server's memory hierarchy includes a secondary cache and a secondary persistent storage that stores a second copy of the set of data blocks. The secondary storage server persistently stores a copy of data, which is also persistently stored on the primary storage server, which includes a first copy of the set of data blocks. In an embodiment, upon receiving the eviction notification, the secondary storage server retrieves the second copy of the set of data blocks from the secondary persistent storage of the secondary storage server and loads the second copy of the set of data blocks into the secondary cache. After an interruption event, the secondary storage receives a request for a subset of the set of data blocks based on a request for data, at the database server. Upon receiving the request for the subset of the set of data blocks, the second storage server retrieves the subset of the set of data blocks from the second copy of the set of data blocks stored on the secondary cache of the secondary storage server without retrieving any of such data blocks from the second copy of the set of data blocks stored on the persistent storage of the secondary storage server. The second storage server sends the subset of the set of data blocks to the database server.

Secondary storage server caching

Growing community of inventors

Mountain View, CA, United States of America

Shih-Yu Huang