Data allocation containers in a partitioned table of a computer database system for holding data based on usage

• US 9,471,614 B2
• Filed: 04/15/2014
• Issued: 10/18/2016
• Est. Priority Date: 09/25/2013
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Konik, Rafal P., Mittelstadt, Roger A., Muras, Brian R., Theuer, Mark W.
• Primary Examiner(s): Perveen, Rehana
• Assistant Examiner(s): Bui, Tiffany Thuy
• Application Number:
  US14/253,583
• Publication Number:
  US 20150088903A1
• Time in Patent Office: 917 Days
• Field of Search: 707/751
• US Class Current: 1/1
• CPC Class Codes: G06F 16/221 Column-oriented storage; Management thereof
• CPC Class Codes: G06F 16/2282 Tablespace storage structures; Management thereof
• CPC Class Codes: G06F 16/2477 Temporal data queries

Abstract

An apparatus and method utilize partitioned database tables divided into data allocation containers (DACs) where data is placed into the DACs based on usage of the data in past queries. Records that are used most often are placed together and records that are used less often are placed together to improve database performance. In preferred embodiments, a database manager determines where to place data into the DACs based on how often the data is selected by a database query using a DAC selection ratio (DSR). The database manager may determine when to perform table maintenance to move rows of data to the appropriate DACs based on a timestamp or last check date (LCD) stored in the database.

Claims

1. A method for allocating data into data allocation containers in a partitioned table of a database comprising:

utilizing a processor to execute computer codes comprising the steps of;

receiving a query to the partitioned table of the database;

selecting at least one row of data in the partitioned table specified by the query;

recording appropriate data regarding the usage of the row of data in the partitioned table by the query to use in allocation of the row of data into a plurality of data allocation containers (DACs) in the partitioned table by;

updating a counter for a number of queries made to the partitioned database table;

incrementing a counter for a number of times selected for each selected row by the query; and

computing a DAC selection ratio (DSR) for each selected row by the query from a quotient of the number of queries made to the partitioned table and the number of times selected; and

at an appropriate time interval moving the row of data accessed by the query from a current DAC to a different DAC in the partitioned table based on the recorded data regarding the usage of the row of data by the query.

2. The method of claim 1 wherein the plurality of DACs includes a high priority DAC placed in a memory device with a faster access time and a low priority DAC placed in a memory device with a slower access time.

3. The method of claim 1 wherein the step of recording appropriate data regarding usage of the row of data further comprises the step of incrementing a counter for a number of time inspected by that indicates how many time the row of data was inspected but not selected.

4. The method of claim 1 wherein the step of moving the row of data accessed by the query further comprises the steps of:

determining if the DAC selection ratio is within a predetermined range for the current DAC; and

moving the row of data to the appropriate DAC where the data selection ratio is not within the predetermined range for the current DAC.

5. The method of claim 1 wherein the step of recording appropriate data regarding usage of the row of data further comprises the step of updating a last accessed time stamp for each selected row by the query;

and wherein the step of moving the row of data accessed by the query further comprises the step of moving the selected row of data to the appropriate DAC based on the last accessed time stamp.

6. The method of claim 1 wherein the step of recording appropriate data regarding usage of the row of data further comprises the step of updating a time based bit map for each selected row by the query;

and wherein the step of moving the row of data accessed by the query further comprises the step of moving the selected row of data to the appropriate DAC based on the time based bit map.

7. The method of claim 6 wherein the time based bit map records a bit for each month the row of data is accessed.

8. A method for allocating data into data allocation containers in a partitioned table of a database comprising:

utilizing a processor to execute computer codes comprising the steps of;

receiving a query to the partitioned table of the database;

selecting at least one row of data in the partitioned table specified by the query;

recording appropriate data in the partitioned table regarding the usage of the row of data in the partitioned table by the query to use in allocation of the row of data into a plurality of data allocation containers (DACs) in the partitioned table comprising the steps of;

updating a counter for a number of queries made to the partitioned database table;

incrementing a counter for a number of times selected for each selected row by the query;

computing a DAC selection ratio (DSR) for each selected row by the query from a quotient of the number of queries made to the partitioned table and the number of times selected;

incrementing a counter for a number of times inspected that indicates how many times the row of data was inspected but not selected; and

at an appropriate time interval moving the row of data accessed by the query from a current DAC to a different DAC in the partitioned table based on the recorded data regarding the usage of the row of data by the query.

9. The method of claim 8 wherein the plurality of DACs includes a high priority DAC placed in a memory device with a faster access time and a low priority DAC placed in a memory device with a slower access time.

10. The method of claim 8, wherein the step of moving the row of data accessed by the query further comprises the steps of:

determining if the DAC selection ratio is within a predetermined range for the current DAC; and

moving the row of data to the appropriate DAC where the data selection ratio is not within the predetermined range for the current DAC.

11. The method of claim 8 wherein the step of recording appropriate data regarding usage of the row of data further comprises the step of updating a last accessed time stamp for each selected row by the query;

and wherein the step of moving the row of data accessed by the query further comprises the step of moving the selected row of data to the appropriate DAC based on the last accessed time stamp.

12. The method of claim 8 wherein the step of recording appropriate data regarding usage of the row of data further comprises the step of updating a time based bit map for each selected row by the query;

and wherein the step of moving the row of data accessed by the query further comprises the step of moving the selected row of data to the appropriate DAC based on the time based bit map.

13. The method of claim 11 wherein the time based bit map records a bit for each month the row of data is accessed.