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：CA2306946A1

公开(公告)日：2001-10-28

申请号：CA2306946

申请日：2000-04-28

Applicant: IBM CANADA

Inventor： ZILIO DANIEL C ,  FINLAY IAN R ,  LOHMAN GUY M ,  SHARPE DAVID C ,  LINDSAY BRUCE G

IPC: G06F17/30

Abstract: A query processing system having a data manager, and a query manager also includes a buffer. The query manager calls the data manager to access data based on a query. Where there is no predicate check or consumption operation on the record accessed, the data manager will notionally return the record to the query manager. However, the data manager accomplishes the retu rn by writing the relevant portions of the record to a buffer. The data manager maintains stabilization of the page containing the record while the buffer is being written to. The data manager continues to access records on the stabilized page and to write such records to the buffer where appropriate. The query manager retrieves the records from the buffer after the data manager has completed its operation resulting from the query manager call.