Oracle International Corporation

Krishna Kunchithapadam

Amit Ganesh

Juan R Loaiza

Tirthankar Lahiri

Jesse Kamp

Michael J Gleeson

Niloy Mukherjee

Vineet Marwah

Shasank Kisan Chavan

Garret Frederick Swart

Vivekanandhan Raja

Dheeraj Pandey

Allison Holloway

Teck Hua Lee

Sanket Hase

Kam Shergill

Neil J S MacNaughton

Siddharth Teotia

Sujatha Muthulingam

Wei Zhang

Ananth Raghavan

Shrikanth Shankar

Ramesh Kumar

Bharat Chandra Baddepudi

Vipin Gokhale

Joy Forsythe

Nirman Kumar

Kaan Baloglu

Allison L Holloway

Neil JS Macnaughton

A hashing scheme includes a cache-friendly, latchless, non-blocking dynamically resizable hash index with constant-time lookup operations that is also amenable to fast lookups via remote memory access. Specifically, the hashing scheme provides each of the following features: latchless reads, fine grained lightweight locks for writers, non-blocking dynamic resizability, cache-friendly access, constant-time lookup operations, amenable to remote memory access via RDMA protocol through one sided read operations, as well as non-RDMA access.

Latchless, non-blocking dynamically resizable segmented hash index

Techniques are provided for enabling a requesting entity to retrieve data that is managed by a database server instance from the volatile memory of a server machine that is executing the database server instance. The techniques allow the requesting entity to retrieve the data from the volatile memory of the host server machine without involving the database server instance in the retrieval operation. Because the retrieval does not involve the database server instance, the retrieval may succeed even when the database server instance has stalled or become unresponsive. In addition, direct retrieval of data using the techniques described herein will often be faster and more efficient than retrieval of the same information through conventional interaction with the database server instance.

Method for efficient primary key based queries using atomic RDMA reads on cache friendly in-memory hash index

Techniques are provided for maintaining data persistently in one format, but making that data available to a database server in more than one format. For example, one of the formats in which the data is made available for query processing is based on the on-disk format, while another of the formats in which the data is made available for query processing is independent of the on-disk format. Data that is in the format that is independent of the disk format may be maintained exclusively in volatile memory to reduce the overhead associated with keeping the data in sync with the on-disk format copies of the data.

Mirroring, in memory, data from disk to improve query performance

Techniques for maintaining a cascading index are provided. In one approach, one or more branch node compression techniques are applied to the main index of a cascading index. In an approach, a Bloom filter is generated and associated with, e.g., a branch node in the main index. The Bloom filter is used to determine whether, without accessing any leaf blocks, a particular key value exists, e.g., in leaf blocks associated with the branch node. In an approach, a new redo record is generated in response to a merge operation between two levels of the cascading index. The new redo record comprises (a) one or more addresses of blocks that are affected by the merge operation, (b) data is that being 'pushed down' to a lower level of the cascading index, and (c) one or more addresses of blocks that are written to storage as a result of the merge operation.

Generating and applying redo records

A method, system and computer program product are described for state maintenance of a large object. In one approach, the method, system and computer program product perform by associating one or more buffers with a transaction involving a large object, the large object data may be accessed using the one or more buffers during the transaction, and storing data for the large object from the one or more buffers in one or more sets of contiguous blocks. In one approach, a system performs state maintenance of a large object with a cache that associates one or more buffers with a transaction involving a large object, the large object data may be accessed using the one or more buffers during the transaction, and the cache stores large object data from the one or more buffers in one or more sets of contiguous blocks in storage.

Method and system for state maintenance of a large object

Techniques for maintaining a cascading index are provided. In one approach, one or more branch node compression techniques are applied to the main index of a cascading index. In an approach, a Bloom filter is generated and associated with, e.g., a branch node in the main index. The Bloom filter is used to determine whether, without accessing any leaf blocks, a particular key value exists, e.g., in leaf blocks associated with the branch node. In an approach, a new redo record is generated in response to a merge operation between two levels of the cascading index. The new redo record comprises (a) one or more addresses of blocks that are affected by the merge operation, (b) data is that being 'pushed down' to a lower level of the cascading index, and (c) one or more addresses of blocks that are written to disk storage as a result of the merge operation.

Querying a cascading index that avoids disk accesses

Techniques for compressing branch nodes in an index are provided. The branch nodes may be part of a main index of a multi-level index that also includes one or more journal indexes. A Bloom filter may be generated and associated with, e.g., a branch node in the main index. The Bloom filter is used to determine whether, without accessing any leaf blocks, a particular key value exists, e.g., in leaf blocks associated with the branch node.

Organizing portions of a cascading index on disk

Techniques are provided for processing a CREATE INDEX statement that avoids one or more locks on the underlying table. The processing of such a statement may be divided into a build phase and a cooperation phase. During the build phase, a journal table is created and published. A snapshot of the table is obtained after the last DML transaction (that was pending at the time the journal table was published) commits. The index is built based on the state of the table as of the snapshot. Any changes to the table while the index is built are recorded in the journal table. During the cooperation phase, the index is partially published. A subsequent DML statement determines whether any changes in the journal table affect the same data as the subsequent DML statement. If so, then those changes are applied to the index followed by the subsequent DML statement.

Online index builds and rebuilds without blocking locks

Disclosed is a system and method for implementing space management for large objects stored in the computing system. According to some approaches, storage of large objects are managed by dynamically creating contiguous chunks of storage space of varying lengths. The length of each chunk may vary depending upon object size being stored, fragmentation of the storage space, available free space, and/or expected length of the object.

Method and mechanism for implementing dynamic space management for large objects

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Portland, OR, United States of America

Krishna Kunchithapadam