Patents by Inventor Sang K. Cha
Sang K. Cha has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
-
Patent number: 9454560Abstract: An optimistic, latch-free index traversal (“OLFIT”) concurrency control scheme is disclosed for an index structure for managing a database system. In each node of an index tree, the OLFIT scheme maintains a latch, a version number, and a link to the next node at the same level of the index tree. Index traversal involves consistent node read operations starting from the root. To ensure the consistency of node read operations without latching, every node update operation first obtains a latch and increments the version number after update of the node contents. Every node read operation begins with reading the version number into a register and ends with verifying if the current version number is consistent with the register-stored version number. If they are the same, the read operation is consistent. Otherwise, the node read is retried until the verification succeeds. The concurrency control scheme of the present invention is applicable to many index structures such as the B+-tree and the CSB+-tree.Type: GrantFiled: November 5, 2007Date of Patent: September 27, 2016Assignee: SAP SEInventors: Sang K. Cha, Sangyong Hwang, Kihong Kim, Keunjoo Kwon
-
Patent number: 9069809Abstract: The apparatuses and methods described herein may operate to identify, from an index structure stored in memory, a reference minimum bounding shape that encloses at least one minimum bounding shape. Each of the at least one minimum bounding shape may correspond to a data object associated with a leaf node of the index structure. Coordinates of a point of the at least one minimum bounding shape may be associated with a set of first values to produce a relative representation of the at least one minimum bounding shape. The set of first values may be calculated relative to coordinates of a reference point of the reference minimum bounding shape such that each of the set of first values comprises a first number of significant bits fewer than a second number of significant bits representing a second value associated with a corresponding one of absolute coordinates of the point.Type: GrantFiled: November 18, 2013Date of Patent: June 30, 2015Assignee: SAP SEInventors: Sang K. Cha, Kihong Kim, Keun-Joo Kwon
-
Publication number: 20140081930Abstract: The apparatuses and methods described herein may operate to identify, from an index structure stored in memory, a reference minimum bounding shape that encloses at least one minimum bounding shape. Each of the at least one minimum bounding shape may correspond to a data object associated with a leaf node of the index structure. Coordinates of a point of the at least one minimum bounding shape may be associated with a set of first values to produce a relative representation of the at least one minimum bounding shape. The set of first values may be calculated relative to coordinates of a reference point of the reference minimum bounding shape such that each of the set of first values comprises a first number of significant bits fewer than a second number of significant bits representing a second value associated with a corresponding one of absolute coordinates of the point.Type: ApplicationFiled: November 18, 2013Publication date: March 20, 2014Applicant: SAP AGInventors: Sang K. Cha, Kihong Kim, Keun-Joo Kwon
-
Patent number: 8589369Abstract: The apparatuses and methods described herein may operate to identify, from an index structure stored in memory, a reference minimum bounding shape that encloses at least one minimum bounding shape. Each of the at least one minimum bounding shape may correspond to a data object associated with a leaf node of the index structure. Coordinates of a point of the at least one minimum bounding shape may be associated with a set of first values to produce a relative representation of the at least one minimum bounding shape. The set of first values may be calculated relative to coordinates of a reference point of the reference minimum bounding shape such that each of the set of first values comprises a first number of significant bits fewer than a second number of significant bits representing a second value associated with a corresponding one of absolute coordinates of the point.Type: GrantFiled: January 27, 2012Date of Patent: November 19, 2013Assignee: SAP AGInventors: Sang K. Cha, Ki-Hong Kim, Keun-Joo Kwon
-
Publication number: 20120124010Abstract: The apparatuses and methods described herein may operate to identify, from an index structure stored in memory, a reference minimum bounding shape that encloses at least one minimum bounding shape. Each of the at least one minimum bounding shape may correspond to a data object associated with a leaf node of the index structure. Coordinates of a point of the at least one minimum bounding shape may be associated with a set of first values to produce a relative representation of the at least one minimum bounding shape. The set of first values may be calculated relative to coordinates of a reference point of the reference minimum bounding shape such that each of the set of first values comprises a first number of significant bits fewer than a second number of significant bits representing a second value associated with a corresponding one of absolute coordinates of the point.Type: ApplicationFiled: January 27, 2012Publication date: May 17, 2012Inventors: Sang K. Cha, Ki-Hong Kim, Keun-Joo Kwon
-
Patent number: 8121987Abstract: A scheme for accessing an index structure using a reference minimum bounding shape is disclosed. In one example embodiment, a reference minimum bounding shape that encloses two or more minimum bounding shapes may be identified from an index structure stored in memory. Each of the two or more minimum bounding shapes may correspond to a data object associated with a corresponding leaf node of the index structure. In one example embodiment, the index structure may be accessed using the reference minimum bounding shape. In one example embodiment, at least one minimum bounding shape of the two or more minimum bounding shapes may be represented in a relative representation calculated relative to the reference minimum bounding shape. Also disclosed are a method, a system and a non-transitory computer-readable storage medium for accomplishing the same scheme as described above.Type: GrantFiled: July 30, 2010Date of Patent: February 21, 2012Assignee: SAP AGInventors: Sang K. Cha, Kihong Kim, Keun-Joo Kwon
-
Publication number: 20100287144Abstract: A scheme for accessing an index structure using a reference minimum bounding shape is disclosed. In one example embodiment, a reference minimum bounding shape that encloses two or more minimum bounding shapes may be identified from an index structure stored in memory. Each of the two or more minimum bounding shapes may correspond to a data object associated with a corresponding leaf node of the index structure. In one example embodiment, the index structure may be accessed using the reference minimum bounding shape. In one example embodiment, at least one minimum bounding shape of the two or more minimum bounding shapes may be represented in a relative representation calculated relative to the reference minimum bounding shape. Also disclosed are a method, a system and a non-transitory computer-readable storage medium for accomplishing the same scheme as described above.Type: ApplicationFiled: July 30, 2010Publication date: November 11, 2010Applicant: SAP AGInventors: Sang K. Cha, Ki-Hong Kim, Keun-Joo Kwon
-
Patent number: 7797296Abstract: A scheme for accessing a multi-dimensional index structure resident in main memory to refer to data objects stored in a database is disclosed. To reduce the amount of accessed index data, the scheme compresses a minimum bounding rectangle (“MBR”). The first step to compress the MBR is to represent the MBR relatively to a reference MBR. The relative representation of an MBR (“RMBR”) is coordinates of the MBR represented relative to coordinates of the reference MBR. In addition, quantization may be performed as an additional step for further compression. In this step, the RMBR is quantized using a finite level of quantization chosen from a given set of quantization levels. Alternatively, a proper node size can be chosen to reduce the index search time.Type: GrantFiled: October 4, 2007Date of Patent: September 14, 2010Assignee: SAP AGInventors: Sang K. Cha, Ki-Hong Kim, Keun-Joo Kwon
-
Patent number: 7305421Abstract: A parallel logging and recovery scheme for highly available main-memory database systems is presented. A preferred embodiment called parallel redo-only logging (“PROL”) combines physical logging and selective replay of redo-only log records. During physical logging, log records are generated with an update sequence number representing the sequence of database update. The log records are replayed selectively during recovery based on the update sequence number. Since the order of replaying log records doesn't matter in physical logging, PROL makes parallel operations possible. Since the physical logging does not depend on the state of the object to which the log records are applied, the present invention also makes it easy to construct a log-based hot standby system.Type: GrantFiled: July 15, 2002Date of Patent: December 4, 2007Assignee: SAP AGInventors: Sang K. Cha, Juchang Lee, Kihong Kim
-
Patent number: 7293028Abstract: An optimistic, latch-free index traversal (“OLFIT”) concurrency control scheme is disclosed for an index structure for managing a database system. In each node of an index tree, the OLFIT scheme maintains a latch, a version number, and a link to the next node at the same level of the index tree. Index traversal involves consistent node read operations starting from the root. To ensure the consistency of node read operations without latching, every node update operation first obtains a latch and increments the version number after update of the node contents. Every node read operation begins with reading the version number into a register and ends with verifying if the current version number is consistent with the register-stored version number. If they are the same, the read operation is consistent. Otherwise, the node read is retried until the verification succeeds. The concurrency control scheme of the present invention is applicable to many index structures such as the B+-tree and the CSB+-tree.Type: GrantFiled: June 4, 2002Date of Patent: November 6, 2007Assignee: SAP AGInventors: Sang K. Cha, Sangyong Hwang, Kihong Kim, Keunjoo Kwon
-
Patent number: 7283987Abstract: A cache-conscious version of the R-tree, called the CR-tree, is disclosed. To pack more entries in a node, the CR-tree compresses MBR keys, which occupy substantial part of the index data. It first represents the coordinates of an MBR key relatively to the lower left corner of its parent MBR to eliminate the leading 0's from the relative coordinate representation. Then, it quantizes the relative coordinates with a fixed number of bits to further cut off the trailing less significant bits. Consequently, the CR-tree becomes significantly wider and smaller than the ordinary R-tree. The experimental and analytical results show that the two-dimensional CR-tree performs search faster than the ordinary R-tree while maintaining similar update performance and consuming less memory space.Type: GrantFiled: March 1, 2002Date of Patent: October 16, 2007Assignee: SAP AGInventors: Sang K. Cha, Ki-Hong Kim, Keun-Joo Kwon
-
Publication number: 20030061537Abstract: A parallel logging and recovery scheme for highly available main-memory database systems is presented. A preferred embodiment called parallel redo-only logging (“PROL”) combines physical logging and selective replay of redo-only log records. During physical logging, log records are generated with an update sequence number representing the sequence of database update. The log records are replayed selectively during recovery based on the update sequence number. Since the order of replaying log records doesn't matter in physical logging, PROL makes parallel operations possible. Since the physical logging does not depend on the state of the object to which the log records are applied, the present invention also makes it easy to construct a log-based hot standby system.Type: ApplicationFiled: July 15, 2002Publication date: March 27, 2003Inventors: Sang K. Cha, Juchang Lee, Kihong Kim
-
Publication number: 20030033328Abstract: An optimistic, latch-free index traversal (“OLFIT”) concurrency control scheme is disclosed for an index structure for managing a database system. In each node of an index tree, the OLFIT scheme maintains a latch, a version number, and a link to the next node at the same level of the index tree. Index traversal involves consistent node read operations starting from the root. To ensure the consistency of node read operations without latching, every node update operation first obtains a latch and increments the version number after update of the node contents. Every node read operation begins with reading the version number into a register and ends with verifying if the current version number is consistent with the register-stored version number. If they are the same, the read operation is consistent. Otherwise, the node read is retried until the verification succeeds.Type: ApplicationFiled: June 4, 2002Publication date: February 13, 2003Inventors: Sang K. Cha, Sangyong Hwang, Kihong Kim, Keunjoo Kwon
-
Publication number: 20020169784Abstract: A cache-conscious version of the R-tree, called the CR-tree, is disclosed. To pack more entries in a node, the CR-tree compresses MBR keys, which occupy substantial part of the index data. It first represents the coordinates of an MBR key relatively to the lower left corner of its parent MBR to eliminate the leading 0's from the relative coordinate representation. Then, it quantizes the relative coordinates with a fixed number of bits to further cut off the trailing less significant bits. Consequently, the CR-tree becomes significantly wider and smaller than the ordinary R-tree. The experimental and analytical results show that the two-dimensional CR-tree performs search faster than the ordinary R-tree while maintaining similar update performance and consuming less memory space.Type: ApplicationFiled: March 1, 2002Publication date: November 14, 2002Inventors: Sang K. Cha, Ki-Hong Kim, Keun-Joo Kwon