International Business Machines Corporation

Viktor Leis

Vijayshankar Raman

Guy Maring Lohman

Ronald Jason Barber

Richard Sefton Sidle

A method includes performing, by a data structure processor, concurrent read and write operations into a hierarchical data structure that includes a mutable tier including extendible hashing, a hash table, and an immutable tier including a concise hash table (CHT) bitmap. Writers acquire latches on the hierarchical data structure elements that the latches modify. The hierarchical data structure elements are directly accessed by readers without acquiring latches. A modify operation is executed by a writer for one or more levels of the hierarchical data structure. When removed portions of the hierarchical data structure are no longer referenced, tracking is performed by use of a combination of a global state value and a copied local state value.

Concurrent reads and inserts into a data structure without latching or waiting by readers

A method includes performing a lookup using a key into a root node of a multi-tier data structure, to find a partition for performing an insert. A lookup for the key is performed on a first level index that is part of a linked data structure. A payload or reference is added to the linked data structure based on data structure criterion, otherwise the key and the payload are added to the linked data structure if the key is not found. A new first level index is created and added to the linked data structure upon the linked data structure remaining unchanged. The key and the payload or reference are added to the new index. Based on merge criterion, a new second level index is created and a portion of content from selected first level and second level indexes are merged for combining into the new second level index.

Fast multi-tier indexing supporting dynamic update

A method includes performing, by a data structure processor, concurrent read and write operations into a hierarchical data structure. Writers acquire latches on the hierarchical data structure elements that the latches modify. The hierarchical data structure elements are directly accessed by readers without acquiring latches. A modify operation is executed by a writer for one or more levels of the hierarchical data structure. When removed portions of the hierarchical data structure are no longer referenced, tracking is performed by use of a combination of a global state value and a copied local state value. The global state value transitions through a non-repeating sequence of values. No longer referenced portions of the hierarchical data structure are tagged with the current global state value.

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Garching, Germany

Viktor Leis