公开(公告)号：US20220215026A1

公开(公告)日：2022-07-07

申请号：US17705305

申请日：2022-03-26

Applicant: Oracle International Corporation

Inventor： Hong Su ,  Sunil P. Chakkappen ,  Mohamed Zait

IPC: G06F16/2453

Abstract: Techniques for processing queries are provided. In one approach, an execution plan for a query includes multiple sub-plans, one or more of which are selected at runtime while one or more other sub-plans are not executed during execution of the execution plan. In another approach, data about misestimate is generated and stored persistently for subsequent queries. In another approach, statistics for a database object are generated automatically and efficiently while the database object is created or data items are added thereto. In another approach, a hybrid histogram is created that includes a feature of frequency histograms and a feature of height-balanced histograms. In another approach, computer jobs are executed in such a way to avoid deadlock. In another approach, changes to a database object trigger a hard parse of a query even though an execution plan already exists for the query.

公开(公告)号：US11113282B2

公开(公告)日：2021-09-07

申请号：US16147511

申请日：2018-09-28

Applicant: Oracle International Corporation

Inventor： Sunil P. Chakkappen ,  Hong Su ,  Mohamed Zait ,  Suratna Budalakoti

IPC: G06F16/00 ,  G06F16/2453 ,  G06F7/14 ,  G06F16/22 ,  G06F16/23 ,  G06F16/951 ,  G06F16/2458

Abstract: Techniques are provided for merging (a) statistics associated with data added to a table in a bulk load operation with (b) statistics associated with data that existed in the table before the bulk load operation. The statistics associated with the bulk load data are generated on-the-fly during the bulk load, and are merged with the pre-existing statistics as part of the same transaction that is used to perform the bulk load operation. Consequently, execution plans for queries that are assigned snapshot times after the commit time of the bulk load transaction will be selected based on the new statistics, while execution plans for queries that are assigned snapshot times before the commit time of the bulk load transaction will be selected based on the pre-existing statistics.

公开(公告)号：US09852185B2

公开(公告)日：2017-12-26

申请号：US14818663

申请日：2015-08-05

Applicant: Oracle International Corporation

Inventor： Hong Su ,  Mohamed Zait ,  Sunil Chakkappen

IPC: G06F17/30

CPC classification number: G06F17/30489

Abstract: A table is processed to determine an approximate NDV for a plurality of groups. For each row, a group based is identified based on one or more group-by columns. A hashed valued is generated by applying a uniform hash function to a value in an NDV column. The hashed value is assigned to a particular bucket based on the values at a first set of bit positions in a binary representation of the hashed value. A bit position value is determined based on for a remaining portion of the binary representation of the hashed value. The bit position value is based on a number of ordered bits in the hashed value that match a particular bit pattern. For each group identified, a maximum bit position (MBP) table is generated. The MBP table stores, for one or more buckets, the maximum bit position value determined for hashed values assigned to a particular bucket.

公开(公告)号：US12111828B2

公开(公告)日：2024-10-08

申请号：US17451047

申请日：2021-10-15

Applicant: Oracle International Corporation

Inventor： Krishna Kantikiran Pasupuleti ,  Mohamed Ziauddin ,  Hong Su ,  Sunil P. Chakkappen

IPC: G06F16/24 ,  G06F16/2453

CPC classification number: G06F16/2453

Abstract: Disclosed is an approach for applying fine-grained hints to obtain optimal control over error handling during query compilation. Using fine-grained hints causes less disruption to the query plans generated by the optimizer as they constrain specific features while retaining scope for the rest of the optimizer functionality. This approach provides a query plan of better quality that avoid errors, particularly in comparison to coarse-grained approaches that restrict processing to earlier database versions or which disables cost-based processing.

公开(公告)号：US20220012240A1

公开(公告)日：2022-01-13

申请号：US17483326

申请日：2021-09-23

Applicant: Oracle International Corporation

Inventor： Mohamed Zait ,  Yuying Zhang ,  Hong Su ,  Jiakun Li

IPC: G06F16/2458 ,  G06N20/00 ,  G06N7/00 ,  G06F16/22

Abstract: Techniques are provided for gathering statistics in a database system. The techniques involve gathering some statistics using an “on-the-fly” technique, some statistics through a “high-frequency” technique, and yet other statistics using a “prediction” technique. The technique used to gather each statistic is based, at least in part, on the overhead required to gather the statistic. For example, low-overhead statistics may be gathered “on-the-fly” using the same process that is performing the operation that affects the statistic, while statistics whose gathering incurs greater overhead may be gathered in the background, while the database is live, using the high-frequency technique. The prediction technique may be used for relatively-high overhead statistics that can be predicted based on historical data and the current value of predictor statistics.

公开(公告)号：US20190102428A1

公开(公告)日：2019-04-04

申请号：US16147521

申请日：2018-09-28

Applicant: Oracle International Corporation

Inventor： Sunil P. Chakkappen ,  Mohamed Zait ,  Christoforus Widodo ,  Hong Su

IPC: G06F17/30

Abstract: Techniques are described for responding to aggregate queries using optimizer statistics already available in the data dictionary of the database in which the database object targeting by the aggregate query resides, without the user creating any additional objects (e.g. materialized views) and without requiring the objects to be loaded into volatile memory in a columnar fashion. The user query is rewritten to produce a transformed query that targets the dictionary tables to form the aggregate result without scanning the user tables. “Accuracy indicators” may be maintained to indicate whether those statistics are accurate. Only accurate statistics are used to answer queries that require accurate answers. The accuracy check can be made during runtime, allowing the query plan of the transformed query to be used regardless of the accuracy of the statistics. For queries that request approximations, inaccurate statistics may be used so long as the statistics are “accurate enough”.

公开(公告)号：US20190102427A1

公开(公告)日：2019-04-04

申请号：US16147511

申请日：2018-09-28

Applicant: Oracle International Corporation

Inventor： Sunil P. Chakkappen ,  Hong Su ,  Mohamed Zait ,  Suratna Budalakoti

IPC: G06F17/30 ,  G06F7/14

Abstract: Techniques are provided for merging (a) statistics associated with data added to a table in a bulk load operation with (b) statistics associated with data that existed in the table before the bulk load operation. The statistics associated with the bulk load data are generated on-the-fly during the bulk load, and are merged with the pre-existing statistics as part of the same transaction that is used to perform the bulk load operation. Consequently, execution plans for queries that are assigned snapshot times after the commit time of the bulk load transaction will be selected based on the new statistics, while execution plans for queries that are assigned snapshot times before the commit time of the bulk load transaction will be selected based on the pre-existing statistics.

公开(公告)号：US20170357692A1

公开(公告)日：2017-12-14

申请号：US15666380

申请日：2017-08-01

Applicant: Oracle International Corporation

Inventor： Hong Su ,  Sunil P. Chakkappen ,  Mohamed Zait

IPC: G06F17/30

CPC classification number: G06F16/24544 ,  G06F16/24542

Abstract: Techniques for processing queries are provided. In one approach, an execution plan for a query includes multiple sub-plans, one or more of which are selected at runtime while one or more other sub-plans are not executed during execution of the execution plan. In another approach, data about misestimate is generated and stored persistently for subsequent queries. In another approach, statistics for a database object are generated automatically and efficiently while the database object is created or data items are added thereto. In another approach, a hybrid histogram is created that includes a feature of frequency histograms and a feature of height-balanced histograms. In another approach, computer jobs are executed in such a way to avoid deadlock. In another approach, changes to a database object trigger a hard parse of a query even though an execution plan already exists for the query.

公开(公告)号：US09727609B2

公开(公告)日：2017-08-08

申请号：US14041952

申请日：2013-09-30

Applicant: Oracle International Corporation

Inventor： Hong Su ,  Sunil P. Chakkappen ,  Mohamed Zait

IPC: G06F17/30

CPC classification number: G06F17/30466 ,  G06F17/30463

Abstract: Techniques for processing queries are provided. In one approach, an execution plan for a query includes multiple sub-plans, one or more of which are selected at runtime while one or more other sub-plans are not executed during execution of the execution plan. In another approach, data about misestimate is generated and stored persistently for subsequent queries. In another approach, statistics for a database object are generated automatically and efficiently while the database object is created or data items are added thereto. In another approach, a hybrid histogram is created that includes a feature of frequency histograms and a feature of height-balanced histograms. In another approach, computer jobs are executed in such a way to avoid deadlock. In another approach, changes to a database object trigger a hard parse of a query even though an execution plan already exists for the query.