Abstract: A system uses a hybrid key-value storage engine that uses log-structured merge tree and a segmented log-structured object store. The system performs garbage collection of stale document versions avoiding index lookup during log segment compaction. The system separates index and document data to minimize write amplification. The system maintains a delete list using a log-structured merge-tree to store stale document sequence numbers and corresponding sizes per log segment. For each log segment from the plurality of log segments, the system determines a measure of fragmentation of the log segment based on sizes of deleted documents of the log segment from the second log-structured merge-tree. If the fragmentation exceeds a threshold, the system initiates a compaction operation for the log segment.

Abstract: A system uses a hybrid key-value storage engine that uses log-structured merge tree and a segmented log-structured object store. The system performs garbage collection of stale document versions avoiding index lookup during log segment compaction. The system separates index and document data to minimize write amplification. The system maintains a delete list using a log-structured merge-tree to store stale document sequence numbers and corresponding sizes per log segment. For each log segment from the plurality of log segments, the system determines a measure of fragmentation of the log segment based on sizes of deleted documents of the log segment from the second log-structured merge-tree. If the fragmentation exceeds a threshold, the system initiates a compaction operation for the log segment.

Abstract: Embodiments relate to managing exclusive control of a shareable resource between a plurality of concurrently executing threads. An aspect includes determining the number of concurrently executing threads waiting for exclusive control of the shareable resource. Another aspect includes, responsive to a determination that the number of concurrently executing threads waiting for exclusive control of the shareable resource exceeds a pre-determined value, one or more of said concurrently executing threads terminating its wait for exclusive control of the shareable resource. Another aspect includes, responsive to a determination that the number of concurrently executing threads waiting for exclusive control of the shareable resource is less than a pre-determined value, one or more of said one or more concurrently executing threads which terminated its wait for exclusive control of the shareable resource, restarting a wait for exclusive control of the shareable resource.

Abstract: Embodiments relate to managing exclusive control of a shareable resource between a plurality of concurrently executing threads. An aspect includes determining the number of concurrently executing threads waiting for exclusive control of the shareable resource. Another aspect includes, responsive to a determination that the number of concurrently executing threads waiting for exclusive control of the shareable resource exceeds a pre-determined value, one or more of said concurrently executing threads terminating its wait for exclusive control of the shareable resource. Another aspect includes, responsive to a determination that the number of concurrently executing threads waiting for exclusive control of the shareable resource is less than a pre-determined value, one or more of said one or more concurrently executing threads which terminated its wait for exclusive control of the shareable resource, restarting a wait for exclusive control of the shareable resource.