METHOD AND SYSTEM FOR ADAPTIVE PRE-FETCHING OF PAGES INTO A BUFFER POOL

• US 20160055257A1
• Filed: 08/18/2015
• Published: 02/25/2016
• Est. Priority Date: 08/20/2014
• Status: Abandoned Application

• Current Assignee: Sachin Sinha
• Original Assignee: Sachin Sinha
• Inventors: SINHA, Sachin
• Application Number:
  US14/829,504
• Publication Number:
  US 20160055257A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 12/00 Accessing, addressing or allocating within memory systems or architectures digital input from, or digital output to record carriers, e.g. to disk storage units, G06F3/06
• CPC Class Codes: G06F 16/24552 Database cache management
• CPC Class Codes: G06F 16/252 between a Database Management System and a front-end application
• CPC Class Codes: G06F 16/9574 of access to content, e.g. by caching

Abstract

The present disclosure provides a method for pre-fetching one or more pages from a database stored on a data storage device is provided. The one or more pages are pre-fetched in a corresponding buffer pool of one or more buffer pools. The method includes initiating the pre-fetching of the one or more pages from the database stored on the data storage device into the corresponding buffer pool of the one or more buffer pools, enabling a decision for pre-fetching the one or more pages from the database to the buffer pool of the one or more buffer pools based on a calculated probability score and fetching the one or more pages asynchronously from the database into the buffer pool of the one or more buffer pools based on the decision. The pre-fetching is done at any instant of time.

Claims

1. A method for pre-fetching one or more pages from a database stored on a data storage device, the one or more pages being pre-fetched in a corresponding buffer pool of one or more buffer pools, the method comprising:

initiating the pre-fetching of the one or more pages from the database stored on the data storage device into the corresponding buffer pool of the one or more buffer pools, wherein the pre-fetching being done at any instant of time,

enabling a decision for pre-fetching the one or more pages from the database to the buffer pool of the one or more buffer pools based on a calculated probability score; and

fetching the one or more pages asynchronously from the database into the buffer pool of the one or more buffer pools based on the decision.

2. The method as recited in claim 1, wherein the pre-fetching comprises:

checking a first plurality of parameters associated with an extent of one or more extents associated with the corresponding buffer pool of the one or more buffer pools, wherein the first plurality of parameters comprises a size of the extent of the one or more extents and an order associated with the extent of the one or more extents;

predicting the pre-fetching of the one or more pages from the database stored on the data storage device, wherein the predicting being performed by checking a preceding sequence of page IDs in the corresponding extent of the one or more extents; and

calculating the probability score for pre-fetching the one or more pages from the database to the buffer pool of the one or more buffer pools based on a second plurality of parameters, wherein the second plurality of parameters comprises a number of the page IDs in the preceding sequence of the size of the extent of the one or more extents and an actual size of the extent of the one or more extents.

3. The method as recited in claim 2, wherein the extent of the one or more extents being associated with the corresponding buffer pool of the one or more buffer pools.

4. The method as recited in claim 2, wherein the order of the extent of the one or more extents being in a sorted increasing order.

5. The method as recited in claim 1, further comprising storing the one or more pages pre-fetched asynchronously from the database into the corresponding buffer pool of the one or more buffer pools.

6. The method as recited in claim 5, wherein the buffer pool of the one or more buffer pools being dynamically selected for storing the pre-fetched one or more pages.

7. The method as recited in claim 1, wherein the fetching further comprises allowing the buffer pool of the one or more buffer pools to pre-fetch the one or more pages.

8. The method as recited in claim 1, further comprising analyzing an availability of a list, wherein the availability being analyzed for unlocking a page list and a LRU list associated with the corresponding buffer pool of the one or more buffer pools, wherein the page list and the LRU list being unlocked when the list being available and wherein the analyzing being done repetitively.

9. The method as recited in claim 1, further comprising updating a read in progress list based on a non-availability of a free list.

10. A method for pre-fetching one or more pages from a database stored on a data storage device, the one or more pages being pre-fetched in a corresponding buffer pool of one or more buffer pools, the method comprising:

receiving a request from a user in form of a query, wherein the request being received for reading data from the database stored on the data storage device and wherein the request being received in real time;

initiating the pre-fetching of the one or more pages from the database stored on the data storage device into the corresponding buffer pool of the one or more buffer pools based on the received request, wherein the pre-fetching being done by reading the one or more pages from the database to the buffer pool of the one or more buffer pools;

enabling a decision for pre-fetching the one or more pages from the database to the buffer pool of the one or more buffer pools, wherein the decision for pre-fetching being taken based on the calculated probability score; and

fetching the one or more pages synchronously from the database into the buffer pool of the one or more buffer pools based on the decision.

11. The method as recited in claim 10, wherein the pre-fetching comprises:

checking a plurality of parameters associated with an extent of one or more extents associated with the corresponding buffer pool of the one or more buffer pools, wherein the plurality of parameters comprises a size of the extent of the one or more extents and an order associated with the extent of the one or more extents;

predicting the pre-fetching of the one or more pages from the database stored on the data storage device, wherein the predicting being performed by checking a preceding sequence of page IDs in the corresponding extent of the one or more extents; and

calculating a probability score for pre-fetching the one or more pages from the database to the buffer pool of the one or more buffer pools.

12. The method as recited in claim 11, wherein the extent of the one or more extents being associated with the corresponding buffer pool of the one or more buffer pools.

13. The method as recited in claim 11, wherein the order of the extent of the one or more extents being in a sorted increasing order.

14. The method as recited in claim 10, further comprising reading the data requested by the user from the corresponding buffer pool of the one or more buffer pools currently storing the data and wherein the data storage device comprises at least one of a hard disk drive and a solid state drive.

15. The method as recited in claim 10, further comprising storing the one or more pages pre-fetched from the database into the corresponding buffer pool of the one or more buffer pools.

16. The method as recited in claim 10, further comprising updating a read in progress list based on a pre-determined criterion, wherein the pre-determined criterion comprises a page list not being null.

17. The method as recited in claim 10, further comprising analyzing whether the database wants to read single data or not, wherein the analyzing being done at regular intervals of time, wherein the analyzing being done when the prediction for the pre-fetching being correct.

18. A computer-program product for pre-fetching one or more pages from a database stored on a data storage device, the one or more pages being pre-fetched in a corresponding buffer pool of one or more buffer pools, comprising:

a computer readable storage medium having a computer program stored thereon for performing the steps of;

initiating the pre-fetching of the one or more pages from the database stored on the data storage device into the corresponding buffer pool of the one or more buffer pools, wherein the pre-fetching being done at any instant of time,

enabling a decision for pre-fetching the one or more pages from the database to the buffer pool of the one or more buffer pools based on a calculated probability score; and

fetching the one or more pages asynchronously from the database into the buffer pool of the one or more buffer pools based on the decision.

19. The computer-program product as recited in claim 18, wherein the pre-fetching comprises:

checking a first plurality of parameters associated with an extent of one or more extents associated with the corresponding buffer pool of the one or more buffer pools, wherein the first plurality of parameters comprises a size of the extent of the one or more extents and an order associated with the extent of the one or more extents;

predicting the pre-fetching of the one or more pages from the database stored on the data storage device, wherein the predicting being performed by checking a preceding sequence of page IDs in the corresponding extent of the one or more extents; and

calculating the probability score for pre-fetching the one or more pages from the database to the buffer pool of the one or more buffer pools based on a second plurality of parameters, wherein the second plurality of parameters comprises a number of the page IDs in the preceding sequence of the size of the extent of the one or more extents and an actual size of the extent of the one or more extents.

20. The computer-program product as recited in claim 18, further comprising storing the one or more pages pre-fetched asynchronously from the database into the corresponding buffer pool of the one or more buffer pools.