Nagavamsi Ponnekanti

US Patent:

6493701, Dec 10, 2002

Filed:

Jul 5, 2001

Appl. No.:

09/900003

Inventors:

Nagavamsi Ponnekanti - Emeryville CA

Assignee:

Sybase, Inc. - Dublin CA

International Classification:

G06F 1730

US Classification:

707 2, 707 5, 707 3, 707 4

Abstract:

A database system implementing a methodology or technique that can be used to optimize processing of nested loop joins of three or more tables (n-ary NLJs for n 2) more efficiently is described. In implementation, upon encountering a failure condition (i. e. , a given join condition does not hold true) from a join operator (scan child), context information (about the failure) is returned (to the n-ary nested-loop join operator) for indicating exactly which condition (i. e. , join condition) failed. This information is tracked in a scan descriptor, which includes a âfail sargâ data field indicating exactly which particular search argument (âsargâ) failed. Based on this information, the system (operating through the n-ary nested-loop join operator) knows exactly which scan child to return back to (i. e. , how far back to go in the join order to fetch the next row). In this manner, the methodology optimizes processing of n-ary nested loop joins by eliminating comparisons that will not hold true for the corresponding join condition (for which the comparisons were to be tested).

US Patent:

6591269, Jul 8, 2003

Filed:

May 18, 2000

Appl. No.:

09/574662

Inventors:

Nagavamsi Ponnekanti - Emeryville CA

Assignee:

Sybase, Inc. - Dublin CA

International Classification:

G06F 1700

US Classification:

707100

Abstract:

A database system providing an efficient methodology for performing an online rebuild of a B+-tree index is described. From a high-level perspective, the method operates by copying the index rows to newly-allocated pages in the key order so that good space utilization and clustering are achieved. The old pages are deallocated during the process. This approach differs from the previously-published online index rebuild algorithms in two ways. First, it rebuilds multiple leaf pages and then propagates the changes to higher levels. Also, while propagating the leaf level changes to higher levels, level 1 pages (i. e. , the level immediately above the leaf level) are reorganized, eliminating the need for a separate pass. The methodology provides high concurrency, does minimal amount of logging, has good performance and does not deadlock with other index operations. Performance study shows that the approach results in significant reduction in logging and CPU time.

US Patent:

6606626, Aug 12, 2003

Filed:

Feb 11, 2000

Appl. No.:

09/502977

Inventors:

Nagavamsi Ponnekanti - Emeryville CA

Assignee:

Sybase, Inc. - Dublin CA

International Classification:

G06F 1730

US Classification:

707 8, 707 10, 707100, 707201, 709203

Abstract:

A Client/Server Database System with an enhanced Lock Manager for improving concurrency is described. The system tracks information about database columns that are updated in the Lock Manager, in addition to the exclusive lock on the data row (in case of data row locking) or data page (in case of data page locking). In particular, a new field, lrcolumns, is added to the systems record lock data structure to track which columns have been modified. When an exclusive lock is requested on a row of the table being updated in the update statement, the Lock Manager sets the value of lrcolumns. In the context of an exclusive lock that was acquired to update one or more columns of a data row, if an exclusive lock was used only to insert or delete (but not update) the data row, the lrcolumns field would be set to 0. Similarly, the lrcolumns field is 0 for locks that are not exclusive locks (e. g. , shared locks).

US Patent:

6792432, Sep 14, 2004

Filed:

Jul 23, 1998

Appl. No.:

09/121791

Inventors:

Hanuma Kodavalla - Union City CA
Nagavamsi Ponnekanti - Emeryville CA

Assignee:

Sybase, Inc. - Dublin CA

International Classification:

G06F 1730

US Classification:

707103, 707 8, 707101, 707102, 707201, 707202

Abstract:

A Client/Server Database System with improved methods for providing access to highly-concurrent data, such as of B-Tree data structures, is described. When the system receives a request to insert a key value into a B-Tree at page that does not have sufficient room, the system must split at the tree at the leaf level. This is done by allocating a new page, and moving some of the key values from the old page to the new page. The split itself propagates upward. To do the split itself, the system obtains address locks for the two pages, and marks both as undergoing âsplitâ (i. e. , a split operation)âthe system sets a Boolean flag or âsplit bitâ to âtrue. â When the split is propagated up, a âside entryâ is added to the old page to point to the newly allocated page. The old page, however, may not have sufficient room for storing this new entry (e. g. , when it is already full).

US Patent:

6363387, Mar 26, 2002

Filed:

Jul 31, 1999

Appl. No.:

09/364981

Inventors:

Nagavamsi Ponnekanti - Emeryville CA
Jameison B. Martin - Oakland CA

Assignee:

Sybase, Inc. - Dublin CA

International Classification:

G06F 1730

US Classification:

707 10, 707201, 707 1

Abstract:

A Client/Server Database System with improved methods for enhancing concurrency using a ârow updateâ bit and deferred locking is described. Data rows in the system are designed to include ROW_DELETE and ROW_UPDATE status bits. When a transaction updates a row, it sets the ROW_UPDATE bit. When a transaction inserts a row, neither the ROW_UPDATE nor the ROW_DELETE status bits are set. When a transaction deletes a row, it sets the ROW_DELETE bit but the contents of the data row are left intact. Methods are described for processing database transactions (e. g. , in response to SQL queries) using these status bits or flags, together with deferred locking techniques, in a manner that reduces locking overhead and increase concurrency. The approach provides a particular performance advantage over systems that employ row-level locking.

US Patent:

20150134692, May 14, 2015

Filed:

Nov 14, 2013

Appl. No.:

14/080552

Inventors:

- Menlo Park CA, US
Dhrubajyoti Borthakur - Sunnyvale CA, US
Nagavamsi Ponnekanti - Fremont CA, US
Haobo Xu - Palo Alto CA, US

International Classification:

G06F 17/30

US Classification:

707769

Abstract:

Technology is disclosed for retrieving data from a specific storage layer of a storage system (“the technology”). A query application programming interface (API) is provided that allows an application to specify a storage layer on which the query should be executed. The query API can be used in a multi-threaded environment which employs a combination of fast threads and slow threads to serve read/write requests from applications. The fast threads are configured to query on a first set of storage layers, e.g., storage layers in a primary storage, while the slow threads are configured to query on a second set of storage layers, e.g., storage layers in a secondary storage. If a fast thread does not find the requested data in the first set, the request is transferred to a slow thread and the fast thread is allocated to another request while the slow thread is serving the current request.

US Patent:

20140188870, Jul 3, 2014

Filed:

Dec 28, 2012

Appl. No.:

13/730698

Inventors:

Dhrubajyoti Borthakur - Sunnyvale CA, US
Nagavamsi Ponnekanti - Fremont CA, US
Jeffrey Rothschild - Los Altos CA, US

International Classification:

G06F 17/30

US Classification:

707736

Abstract:

A variety of methods for improving efficiency in a database system are provided. In one embodiment, a method may comprise: generating multiple levels of data according to how recently the data have been updated, whereby most recently updated data are assigned to the newest level; storing each level of data in a specific storage tier; splitting data stored in a particular storage tier into two or more groups according to access statistics of each specific data; during compaction, storing data from different groups in separate data blocks of the particular storage tier; and when a particular data in a specific data block is requested, reading the specific data block into a low-latency storage tier.