Richard L. Cole - Los Gatos CA, US Yijou Chen - Cupertino CA, US William J. McKenna - Oceanside CA, US Sergei Perfilov - San Jose CA, US Aman Sinha - San Jose CA, US Eugene Szedenits, Jr. - Ypsilanti MI, US
Assignee:
Paraccel, Inc. - Campbell CA
International Classification:
G06F 7/00 G06F 17/30
US Classification:
707714, 707716, 707718, 707719
Abstract:
A system and/or method are implemented to process queries to a database. In particular, the processing of queries to the database is enhanced by enhancing the determination of join orders of tables implicated in queries. Join orders between relatively large numbers of tables are determined by dividing the set of tables to be ordered into a plurality of subsets of tables, and ordering the individual subsets of tables.
Richard L. Cole - Los Gatos CA, US Yijou Chen - Cupertino CA, US William J. McKenna - Oceanside CA, US Sergei Perfilov - Sunnyvale CA, US Aman Sinha - San Jose CA, US Eugene Szedenits, Jr. - Ypsilanti MI, US
Assignee:
Paraccel, Inc. - Campbell CA
International Classification:
G06F 7/00 G06F 17/30
US Classification:
707714, 707716, 707718, 707719
Abstract:
A system and/or method are implemented to process queries to a database. In particular, the processing of queries to the database is enhanced by enhancing the determination of join orders of tables implicated in queries. Join orders between relatively large numbers of tables are determined by dividing the set of tables to be ordered into a plurality of subsets of tables, and ordering the individual subsets of tables.
Use Of Multi-Join Operator And Rules As Framework For Join Tree Processing In Database Systems
Awny Al-Omari - Cedar Park TX, US Kashif Siddiqui - Austin TX, US Sergei Perfilov - Cupertino CA, US
International Classification:
G06F 17/30
US Classification:
707004000
Abstract:
Methods and systems receive a normalized query tree and analyze the tree to collect information about join operators and their children, and tables in an associated query. This information is then made available to a rule based optimizer that is configured to produce, from the normalized query tree, an execution plan. In addition, in at least some embodiments, an extensible framework is provided for join order optimization via the use of a multi-join operator and multi-join rules as part of the general framework of a query optimizer.
Estimating Statistics For Generating Execution Plans For Database Queries
- Campbell CA, US Sergei Perfilov - San Jose CA, US
International Classification:
G06F 17/30
Abstract:
A database system identifies missing statistics that is not available for processing database queries and determines the missing statistics. The database system generates execution plans for database queries. The database system requests certain statistical information for generating a database query. If the database system determines that the requested statistical information is not available, the database system stores information describing the requested statistical information as missing statistics. The missing statistics may identify one or more columns associated with tables processed by the database query. The database system performs statistical analysis of database tables to generate the missing statistics so that the statistical information is available for generating execution plans for subsequent queries. The database system may rank the missing statistics based on the number of times the missing statistics was identified by the database system while processing database queries.
Limiting Plan Choices For Database Queries Using Plan Constraints
- Campbell CA, US Richard L. Cole - Los Gatos CA, US Yijou Chen - Cupertino CA, US Sergei Perfilov - San Jose CA, US Aman Sinha - San Jose CA, US Eugene Szedenits, Jr. - Ypsilanti MI, US
International Classification:
G06F 17/30
US Classification:
707714, 707718
Abstract:
A database system allows users to specify plan constraint specification that limit choices of execution plans considered by an optimizer of the database system for optimizing database queries. The plan constraint specification specifies attributes of execution plans. The plan constraint specification may identify tables/intermediate results that the plan constraint is applicable to using table names or aliases. The database system applies the plan constraint specification to database queries that match the tables/aliases specified in the plan constraint specification. The database system limits the choice of execution plans evaluated for a database query to execution plans satisfying the attributes specified in an applicable plan constraint specification. The plan constraint specification may specify distribution of a table, a join order for tables, the join mechanism, cardinality of a table or intermediate result, and so on.
- Campbell CA, US Richard L. Cole - Los Gatos CA, US Yijou Chen - Cupertino CA, US Sergei Perfilov - San Jose CA, US Aman Sinha - San Jose CA, US Eugene Szedenits, JR. - Ypsilanti MI, US
International Classification:
G06F 17/30
US Classification:
707714, 707718
Abstract:
A database system rewrites database queries based on rewrite constraints specification. The rewrite constraints specification provides directives to the database system to generate temporary tables for storing intermediate results of database queries and rewrite the corresponding database queries in terms of the temporary tables. The subqueries for matching the rewrite constraints specification may be specified in various ways. For example, the rewrite constraints specification may identify the subqueries by using one or more aliases. The rewrite constraints specification may specify a list of tables such that all database queries that join the database tables specified in the rewrite constraints specification are determined to match. The optimizer is able to optimize the rewritten database queries better by getting a better estimate for the statistics describing the temporary tables.
- Campbell CA, US Yijou Chen - Cupertino CA, US William J. McKenna - Oceanside CA, US Sergei Perfilov - Sunnyvale CA, US Aman Sinha - San Jose CA, US Eugene Szedenits, JR. - Ypsilanti MI, US
Assignee:
ParAccel, Inc. - Campbell CA
International Classification:
G06F 17/30
US Classification:
707714
Abstract:
A system and/or method are implemented to process queries to a database. In particular, the processing of queries to the database is enhanced by enhancing the determination of join orders of tables implicated in queries. Join orders between relatively large numbers of tables are determined by dividing the set of tables to be ordered into a plurality of subsets of tables, and ordering the individual subsets of tables.