U.S. patent application number 17/017757 was filed with the patent office on 2022-03-17 for system and method of optimizing rollbacks.
The applicant listed for this patent is Kyndryl, Inc.. Invention is credited to Sriram Lakshminarasimhan, Sundar Sarangarajan, Prasanna Veeraraghavan, Chandan Kumar Vishwakarma.
Application Number | 20220083469 17/017757 |
Document ID | / |
Family ID | |
Filed Date | 2022-03-17 |
United States Patent
Application |
20220083469 |
Kind Code |
A1 |
Lakshminarasimhan; Sriram ;
et al. |
March 17, 2022 |
SYSTEM AND METHOD OF OPTIMIZING ROLLBACKS
Abstract
A computer-implemented method of optimizing data rollback is
disclosed. The method receives a request to perform a task on a
disk storage. The method initiates the task by reading a plurality
of data pages from the disk storage to a database buffer. Each of
the plurality of data pages on the database buffer are modified to
form a plurality of dirty pages. In response to reaching and/or
exceeding a database buffer threshold, a portion of the plurality
of dirty pages on the database buffer are externalized to a
rollback buffer. In response to reaching and/or exceeding a
rollback buffer threshold, a subset of the portion of the plurality
of dirty pages on the rollback buffer are externalized to the disk
storage. The method detects a task cancelling activity prior to
completion of the task; and performs a rollback of the plurality of
dirty pages to a pre-task state.
Inventors: |
Lakshminarasimhan; Sriram;
(Chennai, IN) ; Veeraraghavan; Prasanna; (Chennai,
IN) ; Vishwakarma; Chandan Kumar; (Hazaribagh,
IN) ; Sarangarajan; Sundar; (Chennai, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kyndryl, Inc. |
New York |
NY |
US |
|
|
Appl. No.: |
17/017757 |
Filed: |
September 11, 2020 |
International
Class: |
G06F 12/0804 20060101
G06F012/0804 |
Claims
1. A computer-implemented method of optimizing data rollback,
comprising: receiving a request to perform a task on at least one
table on a disk storage; initiating the task by reading a plurality
of data pages from the at least one table to a database buffer;
modifying, based on the task, each of the plurality of data pages
on the database buffer to form a plurality of dirty pages;
externalizing, in response to reaching and/or exceeding a database
buffer threshold, a portion of the plurality of dirty pages on the
database buffer to a rollback buffer; externalizing, in response to
reaching and/or exceeding a rollback buffer threshold, a subset of
the portion of the plurality of dirty pages on the rollback buffer
to the disk storage; detecting a task cancelling activity prior to
completion of the task; and responsive to detecting the task
cancelling activity, performing a rollback of the plurality of
dirty pages to a pre-task state.
2. The computer-implemented method of claim 1, wherein performing a
rollback comprises transferring the subset of the portion of the
plurality of dirty pages externalized to the disk storage to the
rollback buffer.
3. The computer-implemented method of claim 1, wherein the database
buffer threshold is reached and/or exceeded based, at least in
part, on a number of the plurality of dirty pages modified on the
database buffer.
4. The computer-implemented method of claim 1, wherein the database
buffer threshold is reached and/or exceeded based, at least in
part, on observing a single system checkpoint.
5. The computer-implemented method of claim 1, wherein the rollback
buffer threshold is reached and/or exceeded based, at least in
part, on observing a predetermined number of the system
checkpoints.
6. The computer-implemented method of claim 1, wherein determining
the task is a rollback eligible task, wherein the dirty pages
associated with the rollback eligible task can be externalized to
the rollback buffer.
7. The computer-implemented method of claim 6, wherein in an
additional task and the rollback eligible task use the database
buffer, wherein only the dirty pages associated with the rollback
eligible task are externalized to the rollback buffer.
8. A computer system of optimizing data rollback, the computer
system comprising: one or more computer processors; one or more
computer readable storage media; computer program instructions; the
computer program instructions being stored on the one or more
computer readable storage media for execution by the one or more
computer processors; and the computer program instructions
including instructions to: receive a request to perform a task on
at least one table on a disk storage; initiate the task by reading
a plurality of data pages from the at least one table to a database
buffer; modify, based on the task, each of the plurality of data
pages on the database buffer to form a plurality of dirty pages;
externalize, in response to reaching and/or exceeding a database
buffer threshold, a portion of the plurality of dirty pages on the
database buffer to a rollback buffer; externalize, in response to
reaching and/or exceeding a rollback buffer threshold, a subset of
the portion of the plurality of dirty pages on the rollback buffer
to the disk storage; detect a task cancelling activity prior to
completion of the task; and responsive to detecting the task
cancelling activity, perform a rollback of the plurality of dirty
pages to a pre-task state.
9. The computer system of claim 8, wherein performing a rollback
comprises transferring the subset of the portion of the plurality
of dirty pages externalized to the disk storage to the rollback
buffer.
10. The computer system of claim 8, wherein the database buffer
threshold is reached and/or exceeded based, at least in part, on a
number of the plurality of dirty pages modified on the database
buffer.
11. The computer system of claim 8, wherein the database buffer
threshold is reached and/or exceeded based, at least in part, on
observing a single system checkpoint.
12. The computer system of claim 8, wherein the rollback buffer
threshold is reached and/or exceeded based, at least in part, on
observing a predetermined number of the system checkpoints.
13. The computer system of claim 8, wherein determining the task is
a rollback eligible task, wherein the dirty pages associated with
the rollback eligible task can be externalized to the rollback
buffer.
14. The computer system of claim 13, wherein in an additional task
and the rollback eligible task use the database buffer, wherein
only the dirty pages associated with the rollback eligible task are
externalized to the rollback buffer.
15. A computer program product for optimizing data rollback, the
computer program product comprising one or more computer readable
storage media and program instructions stored on the one or more
computer readable storage media, the program instructions including
instructions to: receive a request to perform a task on at least
one table on a disk storage; initiate the task by reading a
plurality of data pages from the at least one table to a database
buffer; modify, based on the task, each of the plurality of data
pages on the database buffer to form a plurality of dirty pages;
externalize, in response to reaching and/or exceeding a database
buffer threshold, a portion of the plurality of dirty pages on the
database buffer to a rollback buffer; externalize, in response to
reaching and/or exceeding a rollback buffer threshold, a subset of
the portion of the plurality of dirty pages on the rollback buffer
to the disk storage; detect a task cancelling activity prior to
completion of the task; and responsive to detecting the task
cancelling activity, perform a rollback of the plurality of dirty
pages to a pre-task state.
16. The computer program product of claim 15, wherein performing a
rollback comprises transferring the subset of the portion of the
plurality of dirty pages externalized to the disk storage to the
rollback buffer.
17. The computer program product of claim 15, wherein the database
buffer threshold is reached and/or exceeded based, at least in
part, on a number of the plurality of dirty pages modified on the
database buffer.
18. The computer program product of claim 15, wherein the database
buffer threshold is reached and/or exceeded based, at least in
part, on observing a single system checkpoint.
19. The computer program product of claim 15, wherein the rollback
buffer threshold is reached and/or exceeded based, at least in
part, on observing a predetermined number of the system
checkpoints.
20. The computer program product of claim 15, wherein determining
the task is a rollback eligible task, wherein the dirty pages
associated with the rollback eligible task can be externalized to
the rollback buffer.
Description
BACKGROUND
[0001] Aspects of the present invention relate generally to
multitier architecture systems, and more particularly to decreasing
time delays associated with large transactions using multitier
architecture systems.
[0002] Multitier architecture systems (i.e., n-tiered architecture)
separate an application into logical components (i.e., tiers) that
each have an assigned role or responsibility. Separating the
application responsibilities into multiple tiers allows for an
increase in scalability and processing capabilities. While various
n-tier architecture systems exist, one of the most common is the
three-tiered architecture system. A three-tiered architecture has a
presentation tier, a logic tier, and a data tier.
[0003] The presentation tier is the topmost level of the
architecture. This tier provides relevant application information
in a user interface to the user and can receive user input.
Examples of a presentation tier can include webpages that allow for
the browsing and purchasing of merchandise. The logic tier
maintains the main application logic and allows for the
coordination of the business logic to control the functionality of
the application. The logic tier can act as an intermediary between
the presentation tier and the data tier. For example, the logic
tier can accept user input from the presentation tier and send the
data to the data tier. The data tier is responsible for data
management of the database server. The data tier can contain the
data storage logic and can retrieve data from database servers and
direct the data to the logic tier where it can be processed by
relevant applications.
[0004] While all tiers within the n-tiered architecture systems
generally communicate with each other, information and data stored
in the third tier (i.e., the data tier) is often protected from
direct access by the users. In order to maintain data integrity,
n-tiered architectures systems have implemented various methods to
limit potential data losses, particularly in situations where a
n-tiered architecture system is processing large data
transactions.
SUMMARY
[0005] According to one embodiment of the present invention, a
computer-implemented method of optimizing data rollback is
disclosed. The computer-implemented method includes receiving a
request to perform a task on at least one table on a disk storage.
The computer-implemented method further includes initiating the
task by reading a plurality of data pages from the at least one
table to a database buffer. The computer-implemented method further
includes modifying, based on the task, each of the plurality of
data pages on the database buffer to form a plurality of dirty
pages. The computer-implemented method further includes
externalizing, in response to reaching and/or exceeding a database
buffer threshold, a portion of the plurality of dirty pages on the
database buffer to a rollback buffer. The computer-implemented
method further includes externalizing, in response to reaching
and/or exceeding a rollback buffer threshold, a subset of the
portion of the plurality of dirty pages on the rollback buffer to
the disk storage. The computer-implemented method further includes
detecting a task cancelling activity prior to completion of the
task. The computer-implemented method further includes responsive
to detecting the task cancelling activity, performing a rollback of
the plurality of dirty pages to a pre-task state.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The drawings included in the present invention are
incorporated into, and form part of, the specification. They
illustrate embodiments of the present invention and, along with the
description, serve to explain the principles of the disclosure. The
drawings are only illustrative of certain embodiments and do not
limit the disclosure.
[0007] FIG. 1 illustrates a network diagram depicting networking
environment 100 in accordance with at least one embodiment of the
present invention.
[0008] FIG. 2 illustrates an embodiment of task 200 during an
exemplary rollback operation in accordance with at least one
embodiment of the present invention.
[0009] FIG. 3 illustrates an embodiment of task 300 during an
exemplary rollback operation in accordance with at least one
embodiment of the present invention.
[0010] FIG. 4 depicts a flowchart diagram showing operational steps
of rollback program 101 in accordance with at least one embodiment
of the present invention.
[0011] FIG. 5A illustrates a cloud computing environment in
accordance with at least one embodiment of the present
invention.
[0012] FIG. 5B illustrates abstraction model layers in accordance
with embodiments of the present invention.
[0013] FIG. 6 illustrates a high-level block diagram of an example
computer system 601 that may be used in implementing one or more of
the methods, tools, and modules, and any related functions,
described herein, in accordance with at least one embodiment of the
present invention.
[0014] While the embodiments described herein are amenable to
various modifications and alternative forms, specifics thereof have
been shown by way of example in the drawings and will be described
in detail. It should be understood, however, that the particular
embodiments described are not to be taken in a limiting sense. On
the contrary, the intention is to cover all modifications,
equivalents, and alternatives falling within the spirit and scope
of the disclosure.
DETAILED DESCRIPTION
[0015] Aspects of the present invention relate generally to
n-tiered architecture systems, and more particularly to decreasing
time delays associated with the rollback of large tasks (e.g.,
transactions) using n-tiered architecture systems. While the
present invention is not necessarily limited to such applications,
various aspects of the disclosure may be appreciated through a
discussion of various examples using this context.
[0016] N-tiered architecture systems can be used to perform various
applications and can be incorporated in different types of
Enterprise Resource Planning (ERP) systems. ERP systems can be
generally defined as a type of business management software
containing a suite of integrated applications that can allow a
business to collect, store, manage and interpret data from various
business activities. ERP systems can track various resources for
business organizations including, but not limited to, purchase
orders, payroll, and customer information.
[0017] Often, applications found in an ERP system require long
running uncommitted tasks (e.g., transactions). During these long
running uncommitted tasks, most or all of the data undergoing the
task or operations is inaccessible/unavailable to the business
organization or user. While time consuming, in some situations
taking several hours to complete, these tasks are a necessary
component of ERP systems and ensure proper resource allocation.
During these tasks, certain situations can arise that result in
cancelling the partially completed task. Because these tasks are
uncommitted, the data associated with the tasks remains
inaccessible/unavailable until a rollback of the data to its
pre-task state is complete (i.e., as if the task was never
initiated). Since these tasks are traditionally composed of large
amounts of data, traditional rollback operations can add several
hours of delay before the data (in its pre-task state) is available
and accessible to the user.
[0018] Embodiments of the present invention are directed to methods
of reducing the amount of time associated with performing rollback
operations, particularly in long running uncommitted tasks.
Embodiments disclosed herein can be configured to provide an
additional buffer (e.g., rollback buffer) that acts as a temporary
storage for modified/updated data during the task and minimizes
and/or delays the amount of data externalized to disk storage. In
these embodiments, if a task is interrupted and/or cancelled, data
contained on the rollback buffer and other database buffers can
quickly and more easily be rolled-back to its pre-task state than
traditional methods of rolling-back data already externalized to
disk storage.
[0019] Turning now to the figures, FIG. 1 illustrates an example
networking environment 100 in accordance with at least one
embodiment of the present invention. FIG. 1 provides an
illustration of only one implementation and does not imply any
limitations with regard to the environments in which different
embodiments may be implemented. Many modifications to the depicted
environment may be made by those skilled in the art without
departing from the scope of the invention as recited by the
claims.
[0020] Networking environment 100 can include network 102, user
device 104, and database 106. Network 102 can be any type or
combination of networks. For example, network 102 can include, but
is not limited to, one or more of: (i) personal area network (PAN),
(ii) local area network (LAN), (iii) metropolitan area network
(MAN), (iv) wide area network (WAN), (v) wireless local area
network (WLAN), (vi) storage area network (SAN), (vii) enterprise
private network (EPN), or (viii) virtual private network (VPN).
Network 102 can refer to an IP network, and may include one or more
wired and/or wireless networks that are capable of receiving and
transmitting data, voice, and/or video signals, including
multimedia signals that include voice, data, and video information.
For example, the different tiers of n-tier architecture 106 can
communicate with various user devices 104 (e.g. tablets, laptops,
smartphones, portable terminals, conferencing device components,
user device 104, etc.) over the Internet. In general, network 102
can be any combination of connections and protocols that will
support communications between rollback program 101, user device
104, database 106, and any other devices (not shown) within
networking environment 100.
[0021] In some embodiments, network 102 can be implemented within a
cloud computing environment, or using one or more cloud computing
services. Consistent with various embodiments, a cloud computing
environment can include a network-based, distributed data
processing system that provides one or more cloud computing
services. Further, a cloud computing environment can include many
computers (e.g., hundreds or thousands of computers or more)
disposed within one or more data centers and configured to share
resources over network 102. Cloud computing is discussed in greater
detail in regard to FIGS. 5A-6.
[0022] User device 104 can be a laptop computer, tablet computer,
smartphone, smartwatch, or any other computing device that allows
for a user to interact with and execute the methods and/or
techniques described herein. User device 104 can represent any
programmable electronic device or combination of programmable
electronic devices, capable of executing machine readable program
instructions and as well as capable of communicating with other
computing devices (not shown) within networking environment 100 via
network 102.
[0023] In embodiments, user device 104 can include a user interface
108. User interface 108 provides an interface between rollback
program 101, each user device 104 and database 106. User interface
108 can be a graphical user interface (GUI), a web user interface
(WUI) or any other suitable interface for a user to interact with
and execute the methods and/or techniques described herein.
[0024] While FIG. 1 depicts networking environment 100 having
distinct components (i.e., user device 108 and database 106 being
separately situated, in some embodiments networking environment 100
is configured, at least in part, in a client-server architecture,
such as a n-tiered architecture (e.g., three-tiered architecture).
In these embodiments, various functions of networking environment
100 can be partitioned and functionally separated into traditional
tiered architecture functions.
[0025] For example, in embodiments where networking environment 100
is a three-tiered architecture, networking environment could have a
presentation tier, a logic tier and a data tier. In these
embodiments, the presentation tier could include user interface 108
which allows a user to interact with networking environment 100 via
user device 104. In embodiments having a three-tiered architecture,
a logic tier, not represented in FIG. 1, could contain the
functional business logic used to drive an applications
capabilities (e.g., ERP system applications). In addition, the
logic tier could act as an intermediary between the presentation
tier and the last tier; and the data tier to interact with database
106.
[0026] In embodiments, database 106 can include a single database
or any number of databases, of any size, configured to provide
proper data management of uncommitted tasks. In embodiments,
database 106 can configure disk storage space and allot memory to
create caches and virtual memory objects (e.g., buffer pools).
Alternatively, in some embodiments, database 106 can represent a
data tier in a n-tiered architecture and can include all the
necessary components required by a data tier for proper data
management. In embodiments, database 106 can include any number of
data tables of information and is capable of storing large amounts
of data in one or more memory arrays. Memory arrays are generally
structured in tables of rows and columns to hold data pages (i.e.,
database unit of storage). In embodiments, database 106 can reside
on a single server, on multiple servers within a cloud computing
environment, on user device 104, and/or on the same physical system
or virtualized system as rollback program 101.
[0027] In embodiments, database 106 can include rollback program
101. Although rollback program 101 is depicted in FIG. 1 as
integrated with database 106, in other embodiments, rollback
program 101 can be remotely located from database 106. For example,
rollback program 101 could be a component of the logic tier of a
n-tier architecture that directly interacts with the data tier or
database 106.
[0028] Turning now to FIG. 2, an illustration of an exemplary
uncommitted task (i.e., without commit) 200 is depicted. FIG. 2
provides an illustration of only one implementation and does not
imply any limitations with regard to the environments in which
different embodiments may be implemented. Many modifications to the
depicted environment may be made by those skilled in the art
without departing from the scope of the invention as recited by the
claims.
[0029] In embodiments, a task can include any number of operations
where data from a database experiences a write operation that
modifies or updates data. In FIG. 2, disk storage 202 can include
at least one database. In some embodiments, disk storage 202 can be
a component of a data tier of a n-tier architecture. Disk storage
202 can be comprised of tables of data, such as table 204, having
columns and rows of data. Rows of data can be organized into blocks
to form a unit of data storage called a data page. One or more
databases, particularly those containing data pages associated with
long running uncommitted tasks (e.g., ERP system transactions), can
have tables having millions of columns and millions of rows of
data. As such, the millions of rows associated with table 204 can
form a plurality of data pages 206. Each of the plurality of data
pages 206 can be configured to be any size, but are often found in
2, 4, 8, 16, and 32 KB sizes.
[0030] Returning to FIG. 2, a task can be initiated on the
plurality of data pages 206 in table 204 on disk storage 202. Once
initiated, the plurality of data pages 206 can be read (direction
arrow 208) to a database buffer 210. Database buffer 210 can be an
area of memory that has been allocated by the database for the
purposes of caching data pages from the database tables. One of the
most resource intensive operations in computer systems is the
reading and writing of data from disk storage 202. This is based at
least in part on the ease with which data on a disk can be
accessed. Database buffer 210 can be configured to be significantly
smaller than disc storage 202. For example, while disk storage 202
could have a data volume of 100 GB, database buffer 210 could have
a data volume around 2-3 GB. Keeping database buffer 210 small can
allow read data pages to be easily and quickly accessible during
the task. Database buffer 210 can be configured to be any size and
hold any amount of data. In various embodiments, a balance is often
struck between keeping the database buffer 210 small enough to
ensure data pages can be easily accessed while also ensuring the
space is large enough for the assigned task.
[0031] In embodiments, particularly in long running uncommitted
tasks, the amount of data and data pages 206 in table 204 exceeds
the size of database buffer 210. As a result, not all of data pages
206 can be read to database buffer 210 at the same time. As data
pages 206 are written to database buffer 210, task 200 can begin to
modify and/or update data pages 206. Once task 200 has modified or
updated data page 206, data page 206 becomes a dirty page 212. In
embodiments, once a data page 206 is modified by task 200 and
becomes a dirty page 212, the dirty pages 212 are not immediately
externalized to disk storage 202. In these embodiments, the number
of dirty pages 212 on database buffer 210 can increase until a
first threshold 214 is reached and/or exceeded. In these
embodiments, dirty pages 212 can be externalized and written (see
directional arrows 216) to disk storage 202. While in some
embodiments all of the dirty pages 212 can be externalized to disk
storage 202, in other embodiments the dirty pages 212 can be
externalized until the count of dirty pages 212 is sufficiently
below the first threshold 214.
[0032] Externalizing or writing the dirty pages 212 to disk storage
202 can free up space to allow more data pages 206 to be read from
table 204. These newly read data pages 206 can then be
modified/updated by task 200 to form additional dirty pages 212,
thereby allowing task 200 to progress. In these embodiments, each
time the first threshold 214 is reached, dirty pages 212 can be
externalized and written to storage disk 202. This can continue
until the task is complete and all dirty pages 212 are externalized
to disk storage 202.
[0033] In embodiments having more than one task or a read operation
simultaneously executed where each task or operation is using the
same database buffer (e.g., database buffer 210), each task's
respective dirty pages (or browsed pages if a read operation) are
counted together when determining if the first threshold 214 has
been reached or exceeded. As a result, in embodiments where
multiple tasks or read operations are being executed,
externalization of dirty pages (e.g., dirty pages 212) to disk
storage 202 occurs more frequently, causing an increase in the
number of pages written to disk storage 202. While in many
situations externalizing data to disk storage 202 is a desirable
outcome, in other situations, externalizing large portions of data
to disk storage 202 prior to task completion can have damaging
consequences, particularly when associated with long running
uncommitted tasks such as that described in FIG. 2.
[0034] In embodiments where a long running uncommitted task is
cancelled or abandoned after partial completion, data (i.e., data
pages 206) remains inaccessible to a user or business organization
until the data has been returned, or rolled-back to its pre-task
state. Returning to FIG. 2, if task 200 was cancelled prior to
completion, not only would all of the modifications made to dirty
pages 212 on database buffer 210 have to be rolled-back (e.g., to
data page 206), but all of the dirty pages 212 externalized to disk
storage 202 would also need to be rolled-back. The rollback of
dirty pages 212 on database buffer 210 is an easier and quicker
process, based at least in part on the dirty pages being easily
accessible on database buffer 210. Dirty pages 212 externalized to
disk storage 202 are usually not as easily or quickly accessible as
data located on database buffer 210, based, at least in part, on
the large size of the disk storage 202. Often, dirty pages 212
externalized to disk storage 202 must be read back to database
buffer 210 (see directional arrow 216) to revert the dirty pages to
their pre-task state (i.e., data pages 206) in order to complete a
rollback or backout. The more dirty pages 212 externalized to disk
storage 202, the longer it takes to complete a rollback of long
running uncommitted tasks. As discussed generally herein, data
undergoing a task is not only unavailable to users for the duration
of the task, but also for the length of time necessary to rollback
the data to its original pre-task state. An inability to access
important data for several hours can have serious financial and
business related implications.
[0035] Embodiments of the present invention are directed to
minimizing the duration and time delay associated with backing out
the modified data pages (i.e., dirty pages) during the rollback,
based at least in part, on minimizing the amount of dirty pages
externalized to the database with the use of a rollback buffer.
[0036] Turning now to FIG. 3, an illustration of an exemplary
uncommitted task 300 is depicted in accordance with at least one
embodiment of rollback program 101 during a rollback or backout.
FIG. 3 has similar structures and configurations as those disclosed
in regard to FIG. 2 and can include at least all or fewer than all
of the same or similar components disclosed in reference to FIG. 2.
FIG. 3 provides an illustration of only one implementation and does
not imply any limitations with regard to the environments in which
different embodiments may be implemented. Many modifications to the
depicted environment may be made by those skilled in the art
without departing from the scope of the invention as recited by the
claims.
[0037] In embodiments, rollback program 101 can receive a request
to perform task 300 on at least one table 304 of data (e.g., data
pages 306) stored on disk storage 302 associated with a database
(e.g., database 106). While embodiments disclosed herein often
refer to task 300 as a long running uncommitted task or
transaction, embodiments can include any task where writing
operations (e.g., adding new data, modifying data, and/or updating
data) are performed on data stored on disk storage 302.
[0038] In some embodiments, rollback program 101 can create and
allocate memory for database buffer 310. While in some embodiments
rollback program 101 can create database buffer 310 to be a
particular pre-determined size, in other embodiments, rollback
program 101 can control and determine the size of the database
buffer 310 created. In these embodiments, rollback program 101 can
consider the type of transaction task 300 to be performed (e.g.,
accessing customer lists, updating account information, etc.), the
amount of data (i.e., data pages) in the at least one table 304 to
be processed, and/or the accessibility of the data on database
buffer 310 in order to configure the size of database buffer
310.
[0039] In embodiments, rollback program 101 can determine if task
300 is a rollback eligible task. In some embodiments, rollback
program 101 is configured to receive additional information
regarding whether task 300 is a rollback eligible task. This
additional information can include, but is not limited to,
receiving input from an administrator identifying that task 300 is
a rollback eligible task or having each task pre-identified as a
rollback eligible task or not. In other embodiments, rollback
program 101 can identify whether a task is a rollback eligible task
based on the amount of data comprised in table 304, whether task
300 is with or without a commit instruction, and the projected
length of time necessary to complete task 300.
[0040] In embodiments where task 300 is determined or identified as
a rollback eligible task, rollback program 101 can use rollback
buffer 318. Rollback buffer 318 can be any type of temporary
storage area in memory, configured to hold blocks of data rows or
data pages (e.g., data page 306 or dirty pages 312) during the
execution of a task or transaction. In embodiments, rollback
program 101 can configure rollback buffer 318 to only receive dirty
pages 312 associated with task 300. Rollback buffer 318 can be a
type of database buffer and may be configured in a similar manner
as database buffer 310. In some embodiments, rollback program 101
can create and/or allocate memory for the creation of a rollback
buffer. Similar to database buffer 310, rollback buffer 318 can be
a predetermined size or rollback program 101 can independently
determine an optimized amount of allotted memory. While FIG. 3
illustrates rollback buffer 318 as being smaller in size compared
to database buffer 310, rollback buffer 318 can be the same size or
larger than database buffer 310.
[0041] In embodiments, once database buffer 310 and rollback buffer
318 are configured, task 300 begins by reading (see directional
arrow 308) data pages 306 from table 304 onto database buffer 310.
In this exemplary embodiment, table 304 can contain data pages
representing millions of rows of data. As discussed generally
herein, database buffer 310 is traditionally only allocated a small
amount of memory to ensure data is easily and quickly accessible
(e.g., database buffer 310 could have 2-3 GBs while disk storage
302 could have 100 GBs). As a result, in some embodiments, the
amount of data pages 306 in table 304 to be processed by task 300
can exceed the size or memory allotted to database buffer 304. As
data pages 306 begin to fill database buffer 310, task 300 can
begin to modify or update each of the data pages 306. After a data
page 306 is modified or updated by task 300 it becomes a dirty page
312.
[0042] As task 300 continues to modify data pages 306, more dirty
pages 312 can be formed on database buffer 310. In embodiments,
rollback program 101 can establish first threshold 314 on database
buffer 310. In these embodiments, first threshold 314 can indicate
that a particular count or storage amount of modified data pages
(i.e., dirty pages 306) has been reached or exceeded.
[0043] If first threshold 314 is reached or exceeded, rollback
program 101 can externalize (see directional arrow 316) at least
some of the dirty pages 312 from database buffer 310 and write them
to rollback buffer 318. While any amount of dirty pages 312 can be
externalized to rollback buffer 318, the amount of dirty pages 312
externalized or written to rollback buffer 318 should be of an
amount sufficient to allow additional data pages 306 to be read
from table 304 to database buffer 310 to be processed by task
300.
[0044] In embodiments, first threshold 314 of database buffer 310
can also be considered reached/exceed (i.e., triggered) during a
database system checkpoint. A system checkpoint can generally be
understood to be a restore point in the database and can be used in
some instances to create backups. System checkpoints can be issued
periodically in database systems or can be triggered by specific
events including, but not limited, to subsystem parameter
checkpoint frequency, active log switch, and/or subsystem restarts.
When a system checkpoint triggers first threshold 314, rollback
program 101 can also externalize dirty pages 312 from database
buffer 310 to rollback buffer 318. In embodiments, first threshold
314 can be considered reached/exceeded in a variety of ways
including, but not limited to, based on the amount of dirty pages
312 reaching/exceeding first threshold 314, when a system
checkpoint is observed during task 300, or a combination thereof.
These embodiments ensure database buffer 310 does not become full
and unable to continue task 300.
[0045] In embodiments, as task 300 continues to process data pages
306, rollback program 101 can continue to externalize dirty pages
312 from database buffer 310 to rollback buffer 318 as first
threshold 316 is repeatedly reached or exceeded and/or triggered by
system checkpoints. As a result of the repeated externalization of
dirty pages 312 from database buffer 310 to rollback buffer 318,
rollback buffer 318 begins to fill its allotted space (i.e.,
available space in rollback buffer 318) with dirty pages 312.
Without rollback buffer 318, dirty pages would be directly
externalized (see directional arrows 320) from database buffer 310
to disk storage 302 (as referenced in FIG. 3). To prevent frequent
externalization of dirty pages 312 on rollback buffer 318 and to
avoid rollback buffer 318 from filling up its allotted memory,
rollback program 101 can configure a second threshold 322 that can
dictate when dirty pages 312 are externalized from rollback buffer
318 to disk storage 310.
[0046] While in some embodiments, rollback program 101 can
configure second threshold 322 to be a specific percentage or ratio
of free allotted memory to occupied memory, in other embodiments
second threshold can be considered reached/exceeded (i.e.,
triggered) by the number of system checkpoints. In these
embodiments, rollback program 101 can be configured to monitor the
count of system checkpoints for the duration of task 300. While
dirty pages 312 on database buffer 310 can be externalized to
rollback buffer 318 each time a system checkpoint is issued, second
threshold 322 can be based on the number of system checkpoints and
can only be reached or exceeded after a particular number of system
checkpoints are observed during task 300. While in some embodiments
second threshold 322 can be selectively set to any number of
observed system checkpoints, in other embodiments second threshold
322 can be set in multiples based on a total number of system
checkpoints. In some embodiments, second threshold 322 may be set
in multiples of 50 system checkpoints. For example, if second
threshold 322 is set to 50/100 system checkpoints, dirty pages 312
on rollback buffer 318 can be externalized to disk storage 302
after every 50 system checkpoints are observed by rollback program
101. In embodiments, second threshold 322 can be considered
reached/exceeded in a variety of ways including, but not limited
to, based on the amount of dirty pages 312 reaching/exceeding
second threshold 314, when a particular number of system
checkpoints are observed during task 300, or a combination thereof.
When second threshold 322 is reached or exceed, rollback program
101 can externalize all or less than all of the dirty pages 312 on
rollback buffer 318 to disk storage 302. In some embodiments,
rollback program 101 can dictate an optimized amount of dirty pages
to externalize to disk storage, based, at least in part, on the
amount of data to be processed by task 300, each time second
threshold 322 is reached or exceeded. Such embodiments can ensure
the majority of dirty pages 312 are not externalized to disk
storage 310 prior to task 300 completion.
[0047] In embodiments, rollback program 101 can detect a task
cancelling activity. Task cancelling activity can be any activity
that prevents the completion of task 300 and can include, but is
not limited to, a user administratively cancelling task 300, a
computer system error, and/or system power failure. If a task
cancelling activity is not detected by rollback program 101, then
task 300 can complete the transaction on table 304 data and
externalize the modified/dirty pages 312 to disk storage 302. If a
task cancelling activity is detected, rollback program 101 can
begin a rollback or back out of the modified pages (i.e., dirty
pages 312) and return data pages 306 to their pre-task form or
state, as if task 300 had not been initiated.
[0048] In embodiments, rollbacks or data backouts can be more
quickly performed on database buffer 310 and rollback buffer 318
than rollbacks or backouts made on disk storage 302. This can be
based, at least in part, on the accessibility of dirty pages 312
located on each database buffer 310, rollback buffer 318 and disk
storage 302. In general, data located on database buffer 310 and
rollback buffer 318 can be easily accessed (i.e., more so than disk
storage 302) based at least in part on each database buffer 310 and
rollback buffer 318 having a smaller amount of allotted memory than
disk storage 302. As discussed herein, the smaller amount of memory
allotted to each the database buffer 310 and rollback buffer 318
the more easily data (e.g., dirty pages 312) can be found by task
300 to be backed-out or rolled-back. Data located on disk storage
302 can require a significant amount of time to access because disk
storage 302 can be significantly larger than either database buffer
310 or rollback buffer 318. In addition, because modifying data
directly on disk storage 302 can be time consuming, particularly
with long running uncommitted transactions, the process of backing
out the modifications made to dirty pages 312 on disk storage 302
can be more quickly performed by reading those dirty pages 312 on
disk storage 302 to either database buffer 310 or rollback buffer
318 to make the rollbacks.
[0049] In embodiments where rollback buffer 318 is used and
rollback program 101 detects a task cancelling activity, the
majority of the dirty pages 312 modified by task 300 can be located
on the rollback buffer and database buffer with only a small
percentage of modified pages (i.e., dirty pages 312) having been
externalized or written to disk storage 302. Keeping the majority
of dirty pages 312 on database buffer 310 and rollback buffer 318
allows for faster data retrieval and processing than if the
majority of dirty pages 312 were located on the disk storage 302;
both during a task and a rollback. Time associated with rollbacks
or backing-out dirty pages 312 after a task cancelling activity is
detected can be reduced in a variety of ways. As discussed herein,
when the majority of dirty pages 312 processed by task 300 are
located on rollback buffer 318 (and/or database buffer 310), dirty
pages 312 are quickly and easily accessible for the rollback
operation. Time associated with a rollback is further reduced by
minimizing the number of dirty pages 312 that have to be
transferred from disk storage 302 to the buffer (either database
buffer 310 or rollback buffer 318) in order to be rolled-back. The
process of finding dirty pages 312 externalized to a usually large
disk storage 302 and transferring the dirty pages 312 back to a
buffer can be an energy and time consuming operation. By minimizing
the number of dirty pages 312 on disk storage 302 that need
transferring to a buffer during a rollback can significantly reduce
the time associated with rollbacks.
[0050] In embodiments, rollback program 101 can monitor the data
backout or rollback and can determine when the data in table 304
has been completely restored to is pre-task 300 state. In these
embodiments, rollback program 101 is completed and access to the
data associated with table 304 can again become accessible to users
and other applications or tasks.
[0051] Turning now to FIG. 4, a flowchart diagram depicting
operational method 400 steps performed by rollback program 101, in
accordance with at least one embodiment of the present invention,
is shown. Method 400 can allow for a more efficient rollback of
data associated with uncommitted tasks, particularly with long
running tasks. FIG. 4 provides an exemplary embodiment and does not
imply any limitations with regard to the environments in which
different embodiments may be implemented. Many modifications to the
depicted environment may be made by those skilled in the art
without departing from the scope of the invention as recited by the
claims.
[0052] In embodiments, method 400 can begin at operational step
S402, where rollback program 101 receives a request to perform a
task on at least one table of a database. In some embodiments,
database buffer 310 can be created when a request to perform a task
is received. In these embodiments, memory can be allocated for
database buffer 310 based, at least in part, on the type of task
requested. For example, a task requiring numerous operations or
large amounts of data pages could allocate a larger amount of
memory to increase the size of database buffer 310 (i.e., to reduce
externalization). Alternatively, a task requiring that data pages
be accessed quickly could allocate a smaller amount of memory and
produce a smaller sized database buffer 310. In other embodiments,
database buffer 310 can be configured prior to the initiation of
the task at a pre-determined size.
[0053] Method 400 proceeds to decision step S404. At decision step
S404, rollback program 101 determines if the task has been
identified as a rollback eligible task. If, at decision step S404,
rollback program 101 determines that the task is not a rollback
eligible task (decision step "NO" branch), the task is completed
and the method 400 ends. If, at decision step S404, rollback
program 101 determines that the task is a rollback eligible task
(decision step "YES" branch) method 400 proceeds to operational
step S406.
[0054] At operational step S406, rollback program 101 can initiate
the task by reading a plurality of pages from the plurality of data
rows of the at least one table on to the database buffer. Method
400 proceeds to operational step S408. At operational step S408,
rollback program 101 begins to modify each of the plurality of
pages on the database buffer, as dictated by the task, to form a
plurality of modified pages. Method 400 proceeds to operational
step S410. At operational step S410, rollback program 101
externalizes modified pages from the database buffer to the
rollback buffer in response to reaching/exceeding a first
threshold. Method 400 proceeds to operational step S412. At
operational step S412, rollback program 101 externalizes modified
pages from the rollback buffer to the disk storage in response to
reaching/exceeding a second threshold.
[0055] Method 400 proceeds to decision step S414. At decision step
S414, rollback program 101 determines if a task cancelling activity
is detected before the task is competed. If, at decision step S414,
rollback program 101 determines that no task cancelling activity is
detected prior to task completion (decision step "NO" branch), then
the task is completed and method 400 ends. In embodiments where a
task is completed, the modified pages can be externalized (i.e.,
from both the database buffer and the rollback buffer) and
committed to the disk storage. If, at decision step S414, rollback
program 101 can determine that task cancelling activity has been
detected prior to task completion (decision step "YES" branch),
method 400 proceeds to operational step S416. At operational step
S416, rollback program 101 can perform a rollback of the modified
data pages (i.e., dirty pages 312) on disk storage 302, database
buffer 310, and rollback buffer 318. In embodiments, rollback
program 101 can transfer dirty pages 312 previously externalized to
disk storage 302 to rollback buffer 318, where dirty pages 312 are
rolled back to their pre-task 300 state. In these embodiments, the
dirty pages can be more quickly accessed on the rollback buffer 318
and the rollback can be accomplished faster. Once the rollback in
operational step S416 is completed, method 400 ends.
[0056] It is to be understood that although this disclosure
includes a detailed description on cloud computing, implementation
of the teachings recited herein are not limited to a cloud
computing environment. Rather, embodiments of the present invention
are capable of being implemented in conjunction with any other type
of computing environment now known or later developed.
[0057] Cloud computing is a model of service delivery for enabling
convenient, on-demand network access to a shared pool of
configurable computing resources (e.g., networks, network
bandwidth, servers, processing, memory, storage, applications,
virtual machines, and services) that can be rapidly provisioned and
released with minimal management effort or interaction with a
provider of the service. This cloud model may include at least five
characteristics, at least three service models, and at least four
deployment models.
[0058] Characteristics are as follows:
[0059] On-demand self-service: a cloud consumer can unilaterally
provision computing capabilities, such as server time and network
storage, as needed automatically without requiring human
interaction with the service's provider.
[0060] Broad network access: capabilities are available over a
network and accessed through standard mechanisms that promote use
by heterogeneous thin or thick client platforms (e.g., mobile
phones, laptops, and PDAs).
[0061] Resource pooling: the provider's computing resources are
pooled to serve multiple consumers using a multi-tenant model, with
different physical and virtual resources dynamically assigned and
reassigned according to demand. There is a sense of portion
independence in that the consumer generally has no control or
knowledge over the exact portion of the provided resources but may
be able to specify portion at a higher level of abstraction (e.g.,
country, state, or datacenter).
[0062] Rapid elasticity: capabilities can be rapidly and
elastically provisioned, in some cases automatically, to quickly
scale out and rapidly released to quickly scale in. To the
consumer, the capabilities available for provisioning often appear
to be unlimited and can be purchased in any quantity at any
time.
[0063] Measured service: cloud systems automatically control and
optimize resource use by leveraging a metering capability at some
level of abstraction appropriate to the type of service (e.g.,
storage, processing, bandwidth, and active user accounts). Resource
usage can be monitored, controlled, and reported, providing
transparency for both the provider and consumer of the utilized
service.
[0064] Service Models are as follows:
[0065] Software as a Service (SaaS): the capability provided to the
consumer is to use the provider's applications running on a cloud
infrastructure. The applications are accessible from various client
devices through a thin client interface such as a web browser
(e.g., web-based e-mail). The consumer does not manage or control
the underlying cloud infrastructure including network, servers,
operating systems, storage, or even individual application
capabilities, with the possible exception of limited user-specific
application configuration settings.
[0066] Platform as a Service (PaaS): the capability provided to the
consumer is to deploy onto the cloud infrastructure
consumer-created or acquired applications created using programming
languages and tools supported by the provider. The consumer does
not manage or control the underlying cloud infrastructure including
networks, servers, operating systems, or storage, but has control
over the deployed applications and possibly application hosting
environment configurations.
[0067] Infrastructure as a Service (IaaS): the capability provided
to the consumer is to provision processing, storage, networks, and
other fundamental computing resources where the consumer is able to
deploy and run arbitrary software, which can include operating
systems and applications. The consumer does not manage or control
the underlying cloud infrastructure but has control over operating
systems, storage, deployed applications, and possibly limited
control of select networking components (e.g., host firewalls).
[0068] Deployment Models are as follows:
[0069] Private cloud: the cloud infrastructure is operated solely
for an organization. It may be managed by the organization or a
third party and may exist on-premises or off-premises.
[0070] Community cloud: the cloud infrastructure is shared by
several organizations and supports a specific community that has
shared concerns (e.g., mission, security requirements, policy, and
compliance considerations). It may be managed by the organizations
or a third party and may exist on-premises or off-premises.
[0071] Public cloud: the cloud infrastructure is made available to
the general public or a large industry group and is owned by an
organization selling cloud services.
[0072] Hybrid cloud: the cloud infrastructure is a composition of
two or more clouds (private, community, or public) that remain
unique entities but are bound together by standardized or
proprietary technology that enables data and application
portability (e.g., cloud bursting for load-balancing between
clouds).
[0073] A cloud computing environment is service oriented with a
focus on statelessness, low coupling, modularity, and semantic
interoperability. At the heart of cloud computing is an
infrastructure that includes a network of interconnected nodes.
[0074] Referring now to FIG. 5A, illustrative cloud computing
environment 510 is depicted. As shown, cloud computing environment
510 includes one or more cloud computing nodes 500 with which local
computing devices used by cloud consumers, such as, for example,
personal digital assistant (PDA) or cellular telephone 500A,
desktop computer 500B, laptop computer 500C, and/or automobile
computer system 500N may communicate. Nodes 500 may communicate
with one another. They may be grouped (not shown) physically or
virtually, in one or more networks, such as Private, Community,
Public, or Hybrid clouds as described hereinabove, or a combination
thereof. This allows cloud computing environment 510 to offer
infrastructure, platforms and/or software as services for which a
cloud consumer does not need to maintain resources on a local
computing device. It is understood that the types of computing
devices 500A-N shown in FIG. 5A are intended to be illustrative
only and that computing nodes 500 and cloud computing 500 and cloud
computing environment 510 can communicate with any type of
computerized device over any type of network and/or network
addressable connection (e.g., using a web browser).
[0075] Referring now to FIG. 5B, a set of functional abstraction
layers provided by cloud computing environment 510 (FIG. 5A) is
shown. It should be understood in advance that the components,
layers, and functions shown in FIG. 5B are intended to be
illustrative only and embodiments of the disclosure are not limited
thereto. As depicted below, the following layers and corresponding
functions are provided.
[0076] Hardware and software layer 515 includes hardware and
software components. Examples of hardware components include:
mainframes 502; RISC (Reduced Instruction Set Computer)
architecture based servers 504; servers 506; blade servers 508;
storage devices 511; and networks and networking components 512. In
some embodiments, software components include network application
server software 514 and database software 516.
[0077] Virtualization layer 520 provides an abstraction layer from
which the following examples of virtual entities may be provided:
virtual servers 522; virtual storage 524; virtual networks 526,
including virtual private networks; virtual applications and
operating systems 528; and virtual clients 530.
[0078] In one example, management layer 540 may provide the
functions described below. Resource provisioning 542 provides
dynamic procurement of computing resources and other resources that
are utilized to perform tasks within the cloud computing
environment. Metering and Pricing 544 provide cost tracking as
resources are utilized within the cloud computing environment, and
billing or invoicing for consumption of these resources. In one
example, these resources may include application software licenses.
Security provides identity verification for cloud consumers and
tasks, as well as protection for data and other resources. User
portal 546 provides access to the cloud computing environment for
consumers and system administrators. Service level management 548
provides cloud computing resource allocation and management such
that required service levels are met. Service Level Agreement (SLA)
planning and fulfillment 550 provide pre-arrangement for, and
procurement of, cloud computing resources for which a future
requirement is anticipated in accordance with an SLA.
[0079] Workloads layer 560 provides examples of functionality for
which the cloud computing environment may be utilized. Examples of
workloads and functions which may be provided from this layer
include: mapping and navigation 562; software development and
lifecycle management 564; virtual classroom education delivery 566;
data analytics processing 568; transaction processing 570; and
rollback operations 572.
[0080] FIG. 6, illustrated is a high-level block diagram of an
example computer system 601 that may be used in implementing one or
more of the methods, tools, and modules, and any related functions,
described herein (e.g., using one or more processor circuits or
computer processors of the computer), in accordance with
embodiments of the present invention. In some embodiments, the
major components of the computer system 601 may comprise one or
more Processor 602, a memory subsystem 604, a terminal interface
612, a storage interface 616, an I/O (Input/Output) device
interface 614, and a network interface 618, all of which may be
communicatively coupled, directly or indirectly, for
inter-component communication via a memory bus 603, an I/O bus 608,
and an I/O bus interface unit 610.
[0081] The computer system 601 may contain one or more
general-purpose programmable central processing units (CPUs) 602A,
602B, 602C, and 602D, herein generically referred to as the CPU
602. In some embodiments, the computer system 601 may contain
multiple processors typical of a relatively large system; however,
in other embodiments the computer system 601 may alternatively be a
single CPU system. Each CPU 602 may execute instructions stored in
the memory subsystem 604 and may include one or more levels of
on-board cache.
[0082] System memory 604 may include computer system readable media
in the form of volatile memory, such as random access memory (RAM)
622 or cache memory 624. Computer system 601 may further include
other removable/non-removable, volatile/non-volatile computer
system storage media. By way of example only, storage system 626
can be provided for reading from and writing to a non-removable,
non-volatile magnetic media, such as a "hard drive." Although not
shown, a magnetic disk drive for reading from and writing to a
removable, non-volatile magnetic disk (e.g., a "floppy disk"), or
an optical disk drive for reading from or writing to a removable,
non-volatile optical disc such as a CD-ROM, DVD-ROM or other
optical media can be provided. In addition, memory 604 can include
flash memory, e.g., a flash memory stick drive or a flash drive.
Memory devices can be connected to memory bus 603 by one or more
data media interfaces. The memory 604 may include at least one
program product having a set (e.g., at least one) of program
modules that are configured to carry out the functions of various
embodiments.
[0083] One or more programs/utilities 628, each having at least one
set of program modules 630 may be stored in memory 604. The
programs/utilities 628 may include a hypervisor (also referred to
as a virtual machine monitor), one or more operating systems, one
or more application programs, other program modules, and program
data. Each of the operating systems, one or more application
programs, other program modules, and program data or some
combination thereof, may include an implementation of a networking
environment. Programs 628 and/or program modules 630 generally
perform the functions or methodologies of various embodiments.
[0084] Although the memory bus 603 is shown in FIG. 6 as a single
bus structure providing a direct communication path among the CPUs
602, the memory subsystem 604, and the I/O bus interface 610, the
memory bus 603 may, in some embodiments, include multiple different
buses or communication paths, which may be arranged in any of
various forms, such as point-to-point links in hierarchical, star
or web configurations, multiple hierarchical buses, parallel and
redundant paths, or any other appropriate type of configuration.
Furthermore, while the I/O bus interface 610 and the I/O bus 608
are shown as single respective units, the computer system 601 may,
in some embodiments, contain multiple I/O bus interface units 610,
multiple I/O buses 608, or both. Further, while multiple I/O
interface units are shown, which separate the I/O bus 608 from
various communications paths running to the various I/O devices, in
other embodiments some or all of the I/O devices may be connected
directly to one or more system I/O buses.
[0085] In some embodiments, the computer system 601 may be a
multi-user mainframe computer system, a single-user system, or a
server computer or similar device that has little or no direct user
interface, but receives requests from other computer systems
(clients). Further, in some embodiments, the computer system 601
may be implemented as a desktop computer, portable computer, laptop
or notebook computer, tablet computer, pocket computer, telephone,
smartphone, network switches or routers, or any other appropriate
type of electronic device.
[0086] It is noted that FIG. 6 is intended to depict the
representative major components of an exemplary computer system
601. In some embodiments, however, individual components may have
greater or lesser complexity than as represented in FIG. 6,
components other than or in addition to those shown in FIG. 6 may
be present, and the number, type, and configuration of such
components may vary.
[0087] As discussed in more detail herein, it is contemplated that
some or all of the operations of some of the embodiments of methods
described herein may be performed in alternative orders or may not
be performed at all; furthermore, multiple operations may occur at
the same time or as an internal part of a larger process.
[0088] The present invention may be a system, a method, and/or a
computer program product at any possible technical detail level of
integration. The computer program product may include a computer
readable storage medium (or media) having computer readable program
instructions thereon for causing a processor to carry out aspects
of the present invention.
[0089] The computer readable storage medium can be a tangible
device that can retain and store instructions for use by an
instruction execution device. The computer readable storage medium
may be, for example, but is not limited to, an electronic storage
device, a magnetic storage device, an optical storage device, an
electromagnetic storage device, a semiconductor storage device, or
any suitable combination of the foregoing. A non-exhaustive list of
more specific examples of the computer readable storage medium
includes the following: a portable computer diskette, a hard disk,
a random access memory (RAM), a read-only memory (ROM), an erasable
programmable read-only memory (EPROM or Flash memory), a static
random access memory (SRAM), a portable compact disc read-only
memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a
floppy disk, a mechanically encoded device such as punch-cards or
raised structures in a groove having instructions recorded thereon,
and any suitable combination of the foregoing. A computer readable
storage medium, as used herein, is not to be construed as being
transitory signals per se, such as radio waves or other freely
propagating electromagnetic waves, electromagnetic waves
propagating through a waveguide or other transmission media (e.g.,
light pulses passing through a fiber-optic cable), or electrical
signals transmitted through a wire.
[0090] Computer readable program instructions described herein can
be downloaded to respective computing/processing devices from a
computer readable storage medium or to an external computer or
external storage device via a network, for example, the Internet, a
local area network, a wide area network and/or a wireless network.
The network may comprise copper transmission cables, optical
transmission fibers, wireless transmission, routers, firewalls,
switches, gateway computers and/or edge servers. A network adapter
card or network interface in each computing/processing device
receives computer readable program instructions from the network
and forwards the computer readable program instructions for storage
in a computer readable storage medium within the respective
computing/processing device.
[0091] Computer readable program instructions for carrying out
operations of the present invention may be assembler instructions,
instruction-set-architecture (ISA) instructions, machine
instructions, machine dependent instructions, microcode, firmware
instructions, state-setting data, configuration data for integrated
circuitry, or either source code or object code written in any
combination of one or more programming languages, including an
object oriented programming language such as Smalltalk, C++, or the
like, and procedural programming languages, such as the "C"
programming language or similar programming languages. The computer
readable program instructions may execute entirely on the user's
computer, partly on the user's computer, as a stand-alone software
package, partly on the user's computer and partly on a remote
computer or entirely on the remote computer or server. In the
latter scenario, the remote computer may be connected to the user's
computer through any type of network, including a local area
network (LAN) or a wide area network (WAN), or the connection may
be made to an external computer (for example, through the Internet
using an Internet Service Provider). In some embodiments,
electronic circuitry including, for example, programmable logic
circuitry, field-programmable gate arrays (FPGA), or programmable
logic arrays (PLA) may execute the computer readable program
instructions by utilizing state information of the computer
readable program instructions to personalize the electronic
circuitry, in order to perform aspects of the present
invention.
[0092] Aspects of the present invention are described herein with
reference to flowchart illustrations and/or block diagrams of
methods, apparatus (systems), and computer program products
according to embodiments of the disclosure. It will be understood
that each block of the flowchart illustrations and/or block
diagrams, and combinations of blocks in the flowchart illustrations
and/or block diagrams, can be implemented by computer readable
program instructions.
[0093] These computer readable program instructions may be provided
to a processor of a computer, or other programmable data processing
apparatus to produce a machine, such that the instructions, which
execute via the processor of the computer or other programmable
data processing apparatus, create means for implementing the
functions/acts specified in the flowchart and/or block diagram
block or blocks. These computer readable program instructions may
also be stored in a computer readable storage medium that can
direct a computer, a programmable data processing apparatus, and/or
other devices to function in a particular manner, such that the
computer readable storage medium having instructions stored therein
comprises an article of manufacture including instructions which
implement aspects of the function/act specified in the flowchart
and/or block diagram block or blocks.
[0094] The computer readable program instructions may also be
loaded onto a computer, other programmable data processing
apparatus, or other device to cause a series of operational steps
to be performed on the computer, other programmable apparatus or
other device to produce a computer implemented process, such that
the instructions which execute on the computer, other programmable
apparatus, or other device implement the functions/acts specified
in the flowchart and/or block diagram block or blocks.
[0095] The flowchart and block diagrams in the Figures illustrate
the architecture, functionality, and operation of possible
implementations of systems, methods, and computer program products
according to various embodiments of the present invention. In this
regard, each block in the flowchart or block diagrams may represent
a module, segment, or portion of instructions, which comprises one
or more executable instructions for implementing the specified
logical function(s). In some alternative implementations, the
functions noted in the blocks may occur out of the order noted in
the Figures. For example, two blocks shown in succession may, in
fact, be accomplished as one step, executed concurrently,
substantially concurrently, in a partially or wholly temporally
overlapping manner, or the blocks may sometimes be executed in the
reverse order, depending upon the functionality involved. It will
also be noted that each block of the block diagrams and/or
flowchart illustration, and combinations of blocks in the block
diagrams and/or flowchart illustration, can be implemented by
special purpose hardware-based systems that perform the specified
functions or acts or carry out combinations of special purpose
hardware and computer instructions.
[0096] The descriptions of the various embodiments of the present
invention have been presented for purposes of illustration, but are
not intended to be exhaustive or limited to the embodiments
disclosed. Many modifications and variations will be apparent to
those of ordinary skill in the art without departing from the scope
and spirit of the described embodiments. The terminology used
herein was chosen to best explain the principles of the
embodiments, the practical application or technical improvement
over technologies found in the marketplace, or to enable others of
ordinary skill in the art to understand the embodiments disclosed
herein.
[0097] Although the present invention has been described in terms
of specific embodiments, it is anticipated that alterations and
modification thereof will become apparent to the skilled in the
art. Therefore, it is intended that the following claims be
interpreted as covering all such alterations and modifications as
fall within the true spirit and scope of the disclosure.
* * * * *