公开(公告)号：CA2876466C

公开(公告)日：2022-07-05

申请号：CA2876466

申请日：2014-12-29

Applicant: IBM CANADA LTD IBM CANADA LIMITEE

Inventor： FINLAY IAN R ,  KELLER JEFFREY M ,  STORM ADAM J ,  ZUZARTE CALISTO P

IPC: G06F16/14 ,  G06F7/00 ,  G06F16/9035

Abstract: An illustrative embodiment for optimizing scans using a Bloom filter synopsis, defines metadata to encode distinct values in a range of values associated with a particular portion of a managed object in a database management system into a probabilistic data structure of a Bloom filter that stores an indicator, encoded in a fixed size bit map with one or more bits, indicating whether an element of the particular portion of the managed object is a member of a set of values summarized in the Bloom filter using a value of / or definitely not in the set using a value of 0. The Bloom filter is compressed to create a compressed Bloom filter. The Bloom filter is added to the metadata associated with the managed object and used when testing for values associated with predicates.

公开(公告)号：CA2876466A1

公开(公告)日：2016-06-29

申请号：CA2876466

申请日：2014-12-29

Applicant: IBM CANADA LTD - IBM CANADA LIMITEE

Inventor： FINLAY IAN R ,  KELLER JEFFREY M ,  STORM ADAM J ,  ZUZARTE CALISTO P

IPC: G06F17/30 ,  G06F7/00

Abstract: An illustrative embodiment for optimizing scans using a Bloom filter synopsis, defines metadata to encode distinct values in a range of values associated with a particular portion of a managed object in a database management system into a probabilistic data structure of a Bloom filter that stores an indicator, encoded in a fixed size bit map with one or more bits, indicating whether an element of the particular portion of the managed object is a member of a set of values summarized in the Bloom filter using a value of / or definitely not in the set using a value of 0. The Bloom filter is compressed to create a compressed Bloom filter. The Bloom filter is added to the metadata associated with the managed object and used when testing for values associated with predicates.

公开(公告)号：CA2306928C

公开(公告)日：2004-05-25

申请号：CA2306928

申请日：2000-04-28

Applicant: IBM CANADA

Inventor： HAAS PETER J ,  LUMBY JOHN E ,  ZUZARTE CALISTO P

IPC: G06F17/30

Abstract: The estimate of the selectivity of a HAVING clause in an SQL query is carrie d out by within a specified time constraint by determining a selectivity estimate for each member in a sample set of group sizes for the HAVING clause using a probabilistic model based on an assumed value distribution. The selectivity estimates for the groups in the sample set are used to interpolate estimates for all possible group sizes and the estimates are combined based on an assumed known group size distribution to provide an estimation of the selectivity for the HAVING clause. Different selectivity estimating approaches are used for each group size based on available time for estimating and on the estimated time to complete the estimate using different technique s.

公开(公告)号：CA2427202A1

公开(公告)日：2004-10-30

申请号：CA2427202

申请日：2003-04-30

Applicant: IBM CANADA

Inventor： MA WENBIN ,  ZUZARTE CALISTO P ,  CHENG QI

IPC: G06F7/00 ,  G06F17/30

Abstract: A method for use with an information retrieval system, in which the method i s ued for transforming a database statement containing a first subquery and a seco nd subquery joined together, the first subquery including a group by operation over a child subquery, the method comprising removing the first subquery from the database statemen t thereby removing the join between the first subquery and the second subquery.

公开(公告)号：CA2363187A1

公开(公告)日：2003-05-19

申请号：CA2363187

申请日：2001-11-19

Applicant: IBM CANADA

Inventor： FINLAY IAN R ,  ZUZARTE CALISTO P

IPC: G06F17/30

Abstract: An optimized query processing system and method for a database system. The database system includes a table of data and an index correlated to both the query and to the table. The optimized query processing system includes an index accessing module adapted to access the index to determine if the table contains an ent ry satisfying a query predicate; and a tablescan module for scanning substantially the entire table and retrieving data satisfying the query. A method is also disclosed for generating database diagnostic data.

公开(公告)号：CA2359296A1

公开(公告)日：2003-04-18

申请号：CA2359296

申请日：2001-10-18

Applicant: IBM CANADA

Inventor： ZUZARTE CALISTO P

IPC: G06F17/30

Abstract: The present invention provides a method of estimating cardinalities using statistical soft constraints in a relational database management system. The statistical soft constraints are generated from statistical information gathered with respect to virtual columns. The virtual columns are the result of operations involving one or more columns in the database. When a query is received, the database management system determines whether any of the virtual columns are of interest because they involve expressions or relations that are also reflected in the query. The database management system then develops statistical soft constraints from the statistical characteristics of the virtual column and uses those statistical soft constraints to assist in estimating t he cardinality of a step in the query plan. The virtual columns may or may not be actually materialized into a column of values.

公开(公告)号：CA2365692A1

公开(公告)日：2002-12-21

申请号：CA2365692

申请日：2001-12-19

Applicant: IBM

Inventor： ZILIO DANIEL C ,  CHEUNG KIT MAN ,  LIGHTSTONE SAM S ,  ZUZARTE CALISTO P ,  BEYER KEVIN S ,  VALENTIN GARY ,  ZAHARIOUDAKIS MARKOS ,  LEUNG TING Y ,  LOHMAN GUY M ,  SIMMEN DAVID E ,  PIRAHESH MIR HAMID ,  COCHRANE ROBERTA J

IPC: G06F17/30 ,  G06F17/60

Abstract: The invention herein provides method and apparatus, including software for determining a set of materialized views or indices of the contents or a subset of the contents of a database in a data processing system to be created for one or more users of the database. The method and apparatus provide method and means for evaluating a workload presented by a user to th e database; evaluating the data processing system characteristics; evaluating the databa se characteristics; and, using the above evaluations for recommending a set of suitable materialized views or indices to the user. Another aspect of the invention, which may be used for a workload presented by a user of a database in a data processing system, provides method and apparatus, including software for determining a set of materialized views or indices of the contents or a subset of the contents of the database, by: generating a plurality of materialized view candidates from evaluation of the workload, data processing system characteristics and database characteristics; estimating statistics for the materialized view candidates such as the numbe r of rows, row size, and column statistics; generating a plurality of potential index candidates by evaluating the workload, data processing system characteristics, database characteristics a nd the materialized view candidates; and, from the materialized view candidates and index candidates selecting a set of suitable materialized views and/or indices for submission to the user.

公开(公告)号：CA2427209A1

公开(公告)日：2004-10-30

申请号：CA2427209

申请日：2003-04-30

Applicant: IBM CANADA

Inventor： ZUZARTE CALISTO P ,  FINLAY IAN R

IPC: G06F16/2453 ,  G06F17/30

Abstract: For an information retrieval system, a query rewrite optimization method for eliminating condition predicates of conditional expressions defining the values of a column that is referenced in the predicate of an SQL query on a view. The method evaluates the query t o identify a view and a predicate referencing a column of the view. The column has values selected by a conditional expression having condition predicates defining respective mutually exclusive ranges of values. The predicate defines a first range of values. A determination is made as to whether one of the condition predicates defines a mutually exclusive range of values that includes the first range of values. And, in response, the query is rewritten to eliminate the condition predicates other than the one condition predicate. The predicate is thus applied directly to the base tables without evaluating the conditional expression.

公开(公告)号：CA2418163A1

公开(公告)日：2004-07-31

申请号：CA2418163

申请日：2003-01-31

Applicant: IBM CANADA

Inventor： LIU LINQI ,  MA WENBIN ,  CHENG QI ,  PIRAHESH HAMID MIR ,  ZUZARTE CALISTO P

IPC: G06F17/30

Abstract: A method of query transformation using window aggregation to transform queri es involving subqueries. An optimizer in a relational database management system transfor ms queries to optimize their efficiency and speed. The method transforms queries that have a subquery, replacing the subquery with a window aggregation function. In the case of a correlated subquery, the window aggregation function is partitioned by a correlated column of a correlated table. All data in the main select, or outer block, of the query that was obtained through references to the correlated table is instead obtained through the new window aggregation subquery. By using windo w aggregation, the aggregation is performed at the same time as the selection of relevant data from the correlated table, thereby compiling all needed data in a single pass through the table or view . Reducing the number of times that tables or views are accessed reduces the computational demands of a query.

公开(公告)号：CA2353015A1

公开(公告)日：2003-01-12

申请号：CA2353015

申请日：2001-07-12

Applicant: IBM CANADA

Inventor： FINLAY IAN R ,  LAI TONY WEN HSUN ,  ZUZARTE CALISTO P ,  ZILIO DANIEL C

IPC: G06F17/30

Abstract: The retrieval of distinct tuples in a relational database management system. In response to a request from a consumer process for distinct tuples in a relational database table matching a defined criteria, a distinct operator component sequentially requests tuples from a source component. The source component access the database table and returns a tuple in the sequence to the distinct operator component. The distinct operator component passes each tuple in the sequence to an auxiliary logger. The auxiliary component receives a tuples from the distinct component and determines if it is distinct from other previously received tuples in the sequence to verify its uniqueness to the distinct operator. Tuples that are verified as unique by the auxiliary logger are returned to the consumer process by the distinct operator upon verification.