公开(公告)号：US10366067B2

公开(公告)日：2019-07-30

申请号：US14572765

申请日：2014-12-16

Applicant: Oracle International Corporation

Inventor： Kam Shergill ,  Vineet Marwah

IPC: G06F17/30 ,  G06F16/22

Abstract: Techniques for compressing leaf blocks of an index are provided. The decision whether (and/or how much) to compress leaf blocks of an index is performed on a per block basis. Thus, for example, some leaf blocks of the index may be compressed while other leaf blocks of the index may be uncompressed. As another example, different leaf blocks of an index may be compressed a different amount. In one technique, a set of index entries is identified for storage in a leaf block. Multiple estimates of potential space savings are calculated for compressing the set of index entries, one estimate for each different variation of a compression technique. The compression technique variation that is associated with the most space savings is selected and applied to the set of index entries. Thus, some techniques prevent negative compression altogether. Additionally, users require no knowledge of the underlying data to perform optimal compression.

公开(公告)号：US20180341653A1

公开(公告)日：2018-11-29

申请号：US15606322

申请日：2017-05-26

Applicant: Oracle International Corporation

Inventor： Siddharth Teotia ,  Krishna Kunchithapadam ,  Jesse Kamp ,  Tirthankar Lahiri ,  Michael J. Gleeson ,  Juan R. Loaiza ,  Garret F. Swart ,  Neil J.S. MacNaughton ,  Kam Shergill

IPC: G06F17/30 ,  G06F15/173 ,  G06F12/1045

Abstract: 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.

公开(公告)号：US20180341596A1

公开(公告)日：2018-11-29

申请号：US15606327

申请日：2017-05-26

Applicant: Oracle International Corporation

Inventor： Siddharth Teotia ,  Krishna Kunchithapadam ,  Tirthankar Lahiri ,  Jesse Kamp ,  Michael J. Gleeson ,  Juan R. Loaiza ,  Garret F. Swart ,  Neil J.S. MacNaughton ,  Kam Shergill

IPC: G06F12/1018 ,  G06F17/30

CPC classification number: G06F12/1018 ,  G06F12/0864 ,  G06F12/0868 ,  G06F12/126 ,  G06F12/128 ,  G06F16/2255 ,  G06F16/2453 ,  G06F16/9014 ,  G06F2212/1041 ,  G06F2212/313 ,  G06F2212/621

Abstract: 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.

公开(公告)号：US20160171053A1

公开(公告)日：2016-06-16

申请号：US14572765

申请日：2014-12-16

Applicant: Oracle International Corporation

Inventor： Kam Shergill ,  Vineet Marwah

IPC: G06F17/30

CPC classification number: G06F16/2272 ,  G06F16/2246

Abstract: Techniques for compressing leaf blocks of an index are provided. The decision whether (and/or how much) to compress leaf blocks of an index is performed on a per block basis. Thus, for example, some leaf blocks of the index may be compressed while other leaf blocks of the index may be uncompressed. As another example, different leaf blocks of an index may be compressed a different amount. In one technique, a set of index entries is identified for storage in a leaf block. Multiple estimates of potential space savings are calculated for compressing the set of index entries, one estimate for each different variation of a compression technique. The compression technique variation that is associated with the most space savings is selected and applied to the set of index entries. Thus, some techniques prevent negative compression altogether. Additionally, users require no knowledge of the underlying data to perform optimal compression.

Abstract translation: 提供了用于压缩索引叶片的技术。 在每个块的基础上执行是否（和/或多少）压缩索引的叶块的决定。 因此，例如，索引的一些叶块可以被压缩，而索引的其他叶块可以被压缩。 作为另一示例，索引的不同叶块可以被压缩不同的量。 在一种技术中，识别一组索引条目以存储在叶块中。 计算潜在空间节省的多个估计，用于压缩索引条目集，对于压缩技术的每个不同变化的一个估计。 选择与最多空间节省相关联的压缩技术变体并将其应用于索引条目集合。 因此，一些技术完全可以防止负压缩。 此外，用户不需要知道基础数据来执行最佳压缩。