公开(公告)号：CA2283052C

公开(公告)日：2002-11-05

申请号：CA2283052

申请日：1999-09-23

Applicant: IBM CANADA

Inventor： LUMBY JOHN E ,  RJAIBI WALID ,  ZUZARTE CALISTO PAUL ,  HORNIBROOK JOHN F

IPC: G06F11/34 ,  G06F11/30 ,  G06F17/60

Abstract: A system and process for evaluating the performance of an operational databa se system without interfering with the normal operation of the operational database system is described. The process involves the creation of a test database which contains the system catalogs of the operational database system as user tables. The test database is used to compile queries using these simulated system catalogs. The access plan generated by the compilation in the test database can then be used to evaluate the performance of the queries.

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：CA2283052A1

公开(公告)日：2001-03-23

申请号：CA2283052

申请日：1999-09-23

Applicant: IBM CANADA

Inventor： RJAIBI WALID ,  LUMBY JOHN E ,  HORNIBROOK JOHN F ,  ZUZARTE CALISTO PAUL

IPC: G06F11/34 ,  G06F11/30 ,  G06F17/60

Abstract: A system and process for evaluating the performance of an operational databa se system without interfering with the normal operation of the operational database system is described. The process involves the creation of a test database which contains the system catalogs of the operational database system as user tables. The test database is used to compile queries using these simulated system catalogs. The access plan generated by the compilation in the test database can then be used to evaluate the performance of the queries.

公开(公告)号：CA2220612A1

公开(公告)日：1999-05-03

申请号：CA2220612

申请日：1997-11-03

Applicant: IBM CANADA

Inventor： HUFFMAN PAUL C ,  DOOLE DOUGLAS J ,  LUMBY JOHN E

IPC: G06F17/30 ,  G06F15/163

Abstract: The invention provides a method and apparatus including a programming product fo r a parallel data processing system having a plurality of nodes interconnected by communication paths, in which one or more sets of data present at one or more so urce nodes of the system is required to be sent on a plurality of communication paths having communication buffers to selected nodes of the database system for processing, a system of communicating the data over the paths between the nodes to avoid deadlocking the processing system, including: accessing data from the one or more source nodes i n subsets of the data; sending the subsets of data on a plurality of paths to the selected nodes of the processing system; if a path of the paths intended for the sending of one or more of the subsets of data becomes blocked, suspending the sending of subsets o f the data on the path for a predetermined time period; if the blocked path becomes ca pable of accepting additional data before the predetermined time period has expired, resu ming the sending of subsets of data on the path; however, if the predetermined time perio d expires without the path becoming available, placing one or more subsequent subsets of d ata intended for the path into an overflow buffer; when the blocked path again becom es free, sending the subsets of data from the overflow buffer on the path to the intended recipient node for processing.

公开(公告)号：CA2306928A1

公开(公告)日：2001-10-28

申请号：CA2306928

申请日：2000-04-28

Applicant: IBM CANADA

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

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：CA2220612C

公开(公告)日：2001-04-24

申请号：CA2220612

申请日：1997-11-03

Applicant: IBM CANADA

Inventor： HUFFMAN PAUL C ,  DOOLE DOUGLAS J ,  LUMBY JOHN E

IPC: G06F17/30 ,  G06F15/163

Abstract: The invention provides a method and apparatus including a programming produc t for a parallel data processing system having a plurality of nodes interconnected b y communication paths, in which one or more sets of data present at one or mor e source nodes of the system is required to be sent on a plurality of communication p aths having communication buffers to selected nodes of the database system for processin g, a system of communicating the data over the paths between the nodes to avoid deadlock ing the processing system, including: accessing data from the one or more source nod es in subsets of the data; sending the subsets of data on a plurality of paths to the selected nodes of the processing system; if a path of the paths intended for the send ing of one or more of the subsets of data becomes blocked, suspending the sending of subse ts of the data on the path for a predetermined time period; if the blocked path become s capable of accepting additional data before the predetermined time period has expired, resuming the sending of subsets of data on the path; however, if the predetermined time p eriod expires without the path becoming available, placing one or more subsequent subsets of data intended for the path into an overflow buffer; when the blocked path again b ecomes free, sending the subsets of data fromthe overflow buffer on the path to the inten ded recipient node for processing.