KR101693687B1 - Method for compressing database by column unit - Google Patents

Abstract

According to an embodiment of the present invention, disclosed is a method for compressing a database on a per-unit column basis, which is performed by a computing device including at least one processor and main memory storing instructions adapted to be performed by the processor. The method for compressing a database on a per-unit column basis may comprise the steps of: determining the first number of rows, for which a compression unit is to be generated, in at least one column disposed in a table of a database; generating a first compression unit by compressing the determined first number rows; comparing a size of the first compression unit with a size of an extent; and determining the second number of rows, for which the compression unit is to be generated, in at least one column based on a result of the comparison.

Description

METHOD FOR COMPRESSING DATABASE BY COLUMN UNIT

The present invention relates to databases, and more particularly, to compression of data in databases.

Recently, a large-scale database management system such as a large amount of fixed or unstructured data sets beyond the ability to collect, store, manage, and analyze data with existing database management tools and big data processing that extracts values from these data and analyzes the results Are being developed.

Since most of the data in the database that stores large amounts of data is composed of strings, it is possible to obtain a high compression efficiency when the data is compressed and stored, thereby storing a large amount of data in a smaller storage space. The economic efficiency can be increased.

However, there is a drawback in that performance may be degraded when data is compressed and stored. Thus, there is a need in the art for a solution that can compress and store data in a database while minimizing performance degradation.

U.S. Patent Publication No. 8,583,692

SUMMARY OF THE INVENTION The present invention has been devised in response to the above-described background art, and is intended to provide a solution capable of compressing and storing a database while minimizing degradation in performance.

A method of column-by-column compression of a database performed in a computing device including at least one processor and a main memory for storing instructions executable by the processor, in accordance with an embodiment of the present invention for realizing the above-mentioned problems. The column-wise compression method of the database comprising the steps of: determining a first number of rows to generate a compression unit for one or more columns located in a table of the database; compressing the determined first number of rows to produce a first Generating a compression unit, comparing the size of the first compression unit with a size of an extent, and determining a second number of rows to generate a compression unit for one or more columns based on the comparison result Step < / RTI >

Alternatively, the extent includes a set of data blocks and may have a predetermined size.

Alternatively, if the size of the first compression unit exceeds the size of the extent as a result of the comparison, it is determined that the size of the first compression unit is an overflow, and if it is determined that overflow has occurred, And determining whether or not information related to the number of generated rows exists.

Alternatively, the step of determining a second number of rows to generate a compression unit for one or more columns based on the comparison result, if there is no information related to the number of rows in which the underflow occurred, And determining a result value obtained by dividing the first number by the first predetermined number as the second number.

Alternatively, the step of determining a second number of rows to generate a compression unit for one or more columns based on the result of the comparison, if there is information about the number of rows in which the underflow occurred, Determining a result value obtained by subtracting the difference between the first number and the number of rows in which the underflow occurred by a second predetermined number, as the second number.

Alternatively, if it is determined that the size of the first compression unit is equal to or less than a predetermined ratio of the size of the extent, the step of judging the underflow as a result of the comparison, And determining whether or not information related to the number of generated rows exists.

Alternatively, the step of determining a second number of rows to generate a compression unit for one or more columns based on the result of the comparison, when there is no information related to the number of rows in which the overflow occurred, And determining the second number as a result of multiplying the first number by a third predetermined number.

Alternatively, the third predetermined number may comprise a number of times the maximum size the compression unit may have divided by the size of the first compression unit.

Alternatively, the step of determining a second number of rows to generate a compression unit for one or more columns based on the result of the comparison, if there is information relating to the number of rows where the overflow occurred, And determining the second number as a result of adding the first number and the number obtained by dividing the difference between the number of rows and the number of rows in which the overflow occurs by a fourth predetermined number.

According to another embodiment of the present invention, a database server that provides column-by-column compression of a database is disclosed. Wherein the database server comprises one or more processors and a memory storing instructions executable on the one or more processors, wherein the one or more processors are located in a table of the database A row number determination module for determining a first number and a second number of rows to generate a compression unit for one or more columns, a compression unit generation module for generating a first compression unit by compressing the determined first number of rows, And a compression unit size comparison module for comparing the size of the first compression unit with the size of the extent.

According to yet another embodiment of the present invention, a computer program stored in a computer readable medium is disclosed that includes a plurality of instructions executed by one or more processors. The computer program comprising instructions for: determining a first number of rows to generate a compression unit for one or more columns located in a table of the database; compressing the determined first number of rows to produce a first compression unit Instructions for comparing the size of the first compression unit with the size of the extent and instructions for determining a second number of rows to generate a compression unit for one or more columns based on the comparison result Command.

The present invention can provide a solution capable of compressing and storing a database while minimizing degradation in performance.

1 is a block diagram of a database server that provides column-based compression of a database according to an embodiment of the present invention.
2 is an exemplary diagram illustrating a compression unit of a database according to one embodiment of the present invention.
3 is a flowchart of a column-by-column compression method of a database according to an embodiment of the present invention.
Figure 4 illustrates a simplified, general schematic diagram of an exemplary computing environment in which embodiments of the present invention may be implemented.

Various embodiments are now described with reference to the drawings, wherein like reference numerals are used throughout the drawings to refer to like elements. In this specification, various explanations are given in order to provide an understanding of the present invention. It will be apparent, however, that such embodiments may be practiced without these specific details. In other instances, well-known structures and devices are provided in block diagram form in order to facilitate describing the embodiments.

The terms "component," "module," system, "and the like, as used herein, refer to a computer-related entity, hardware, firmware, software, combination of software and hardware, or execution of software. For example, a component may be, but is not limited to, a process executing on a processor, a processor, an object, an executing thread, a program, and / or a computer. For example, both an application running on a computing device and a computing device may be a component. One or more components may reside within a processor and / or thread of execution, one component may be localized within one computer, or it may be distributed between two or more computers. Further, such components may execute from various computer readable media having various data structures stored therein. The components may be, for example, a signal (e.g., a local system, data from one component interacting with another component in a distributed system, and / or data over a network, such as the Internet, Lt; RTI ID = 0.0 > and / or < / RTI >

The description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features presented herein.

1 is a block diagram of a database server that provides column-based compression of a database according to an embodiment of the present invention.

The database server 100 according to an embodiment of the present invention may include one or more processors, main memory 150, and persistent storage 190. The one or more processors may include a row number determination module 110, a compression unit generation module 130, and a compression unit size comparison module 150.

The database is organized in a table, comprising one or more rows, and one row is composed of one or more columns. In one embodiment of the present invention, column-based compression may comprise collecting identical columns in a plurality of rows to construct a compression unit, and applying compression on a column-by-column basis.

The memory 150 is configured to store various types of data to support the operation of the server 100. Also, the memory 150 may temporarily store the compression unit 200, and may store information related to the number of rows where an underflow has occurred, information relating to the number of rows overflowed. Memory 150 may be any type of memory such as dynamic random access memory (DRAM), static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read- Volatile or non-volatile memory devices, or a combination thereof.

The persistent storage device 190 is configured to store data of the database. The persistent storage device 190 may include other storage media other than the memory 150 of the server 100, such as a hard disk drive (HDD) or a solid state drive (SSD). Memory 150 or persistent storage 190 may comprise a plurality of blocks of data. An extent may comprise a set of data blocks.

The row count determination module 110 may determine the number of rows to generate a compression unit for one or more columns located in the table of the database. The row count determination module 110 may determine the number of rows to be included in the compression unit to compress and store the database. The row number determination module 110 may determine the rows for which the compression unit generation module 130 will generate the compression unit. The row number determination module 110 determines the number of rows to generate the compression unit again based on the comparison result of the compression unit size comparison module 150 after the compression unit generation module 130 generates the first compression unit .

The row number determination module 110 determines whether the compression unit size comparison module 150 determines that the size of the first compression unit exceeds the size of the extent (in the case of determining overflow) The number of rows (the second number of rows) to be included in the unit can be determined to be smaller than the first number of rows.

In addition, when the compression unit size comparison module 150 determines that the size of the first compression unit is equal to or less than a preset ratio of the extent size (when determining that the size of the first compression unit is underflow), the row number determination module 110 next The number of rows (the second number of rows) to be included in the resulting compression unit may be determined to be greater than the first number of rows.

When all of one compression unit is included in one extent, the performance of the database can be enhanced. Accordingly, when a plurality of rows are included in the compression unit and the size of the extents is exceeded, the number of rows included in the compression unit can be reduced to reduce the size of the compression unit to be less than the size of the extent. In addition, even if the compression unit includes too few rows, the efficiency of the database may deteriorate even when a lot of empty space remains in the extent where the compression unit is included. Therefore, the number of rows included in the compression unit is increased, It is possible to prevent the size of the magnetic recording medium from becoming too small.

The row number determination module 110 determines whether the compression unit generation module 130 generates a compression unit having a smaller size when an overflow occurs because the size of the first compression unit exceeds the size of the extent, The number of rows to be included in the compression unit can be reduced. At this time, the row number determination module 110 determines the number of rows to be included in the subsequent compression unit in a different manner, depending on whether or not there is information relating to the number of rows where the underflow occurred when the compression unit was previously generated You can decide.

If there is no information related to the number of rows underflow, the row number determination module 110 may determine the result of dividing the first number of rows by the first predetermined number as the second number of rows.

라 하고, 새로운 압축 유닛을 생성할 로우들의 제 2 개수를

, 제 1 사전 결정된 수를 x1으로 둔다면, 양자는 수학식 1의 관계를 가질 수 있다. More specifically, the first number of rows included in the first compression unit

, And the second number of rows to create a new compression unit

, And if the first predetermined number is x1, then both can have the relationship of Equation (1).

Wherein the first predetermined number may comprise any positive number. For example, the first predetermined number may comprise two. The first predetermined number (x1) may be a sufficient number to prevent the overflow from repeating in the next compression unit generation.

When there is information on the number of rows in which the underflow occurs, the row number determination module 110 determines the number of rows in which the underflow has occurred by dividing the difference between the first number and the number of rows underflowed by the second predetermined number Can be determined as the second number of rows.

라 하고, 새로운 압축 유닛을 생성할 로우들의 제 2 개수를

, 제 2 사전 결정된 수를 x2, 언더플로우가 발생한 로우의 수를

로 둔다면, 양자는 수학식 2의 관계를 가질 수 있다. More specifically, the first number of rows included in the first compression unit

, And the second number of rows to create a new compression unit

The second predetermined number is x2, the number of rows in which the underflow occurs is

, The two can have the relationship of Equation (2).

Where the second predetermined number may comprise any positive number. For example, the second predetermined number may comprise two.

The row number determination module 110 generates a compression unit having a larger size when the first compression unit generates an underflow in which the size of the first compression unit is less than a predetermined ratio of the size of the extent , The number of rows to be included in the compression unit can be increased. At this time, the row number determination module 110 determines the number of rows to be included in the subsequent compression unit in a different manner, depending on whether there is information about the number in the row where the overflow occurred when the compression unit was previously generated You can decide.

If there is no information related to the number of overflowed rows, the row number determination module 110 may determine a second number of result values of the first number of rows multiplied by a third predetermined number.

라 하고, 새로운 압축 유닛을 생성할 로우들의 제 2 개수를

, 제 3 사전 결정된 수를 x3으로 둔다면, 양자는 수학식 3의 관계를 가질 수 있다. More specifically, the first number of rows included in the first compression unit

, And the second number of rows to create a new compression unit

, And if the third predetermined number is set to x3, then both can have the relationship of Equation (3).

를 포함할 수 있다. 제 3 사전 설정된 수(x3)는 다음 번의 압축 유닛 생성시 언더플로우가 반복되는 것을 방지하기에 충분한 수를 포함할 수 있다. Wherein the third predetermined number may comprise any positive number. For example, the third predetermined number is the number of times the maximum size (MaxBytesInCU) that the compression unit can have, divided by the size of the first compression unit (BytesInCurrentCU)

. ≪ / RTI > The third predetermined number (x3) may include a number sufficient to prevent the underflow from repeating at the next compression unit creation.

If there is information on the number of rows in which the overflow occurs, the row number determination module 110 determines the number of rows in which overflow has occurred by dividing the difference between the first number of rows and the number of generated rows by a fourth predetermined number, The resultant value can be determined as the second number.

라 하고, 새로운 압축 유닛을 생성할 로우들의 제 2 개수를

, 제 4 사전 결정된 수를 x4, 언더플로우가 발생한 로우의 수를

로 둔다면, 양자는 수학식 4의 관계를 가질 수 있다. More specifically, the first number of rows included in the first compression unit

, And the second number of rows to create a new compression unit

, The fourth predetermined number is x4, the number of rows in which the underflow occurs

, The two can have the relationship of Equation (4).

Where the fourth predetermined number may comprise any positive number. For example, the fourth predetermined number may comprise two.

The compression unit generation module 130 may compress the determined number of rows in the row number determination module 110 to generate a compression unit. The compression unit may include the contents of the columns corresponding to the row of the database. The compression unit generation module 130 may compress the data through any compression algorithm. The compression unit generation module 130 may record information for reading data included in the compression unit in the compression unit header 230, information for identifying data included in the compression unit.

The compression unit size comparison module 150 can compare the size of the generated compression unit with the size of the extents. The compression unit size comparison module 150 can determine that the compression unit is overflow when the size of the compression unit exceeds the size of the extent. In the case where an overflow occurs, data included in one compression unit is recorded in two or more extents. Therefore, a database for responding to a query for data inquiry such as OLAP (online analytical processing) or OLTP (online transaction processing) Performance may be degraded. Accordingly, when the overflow occurs, the compression unit size comparison module 150 determines whether the row number determination module 110 determines that the size of the compression unit generated by the compression unit generation module 130 does not exceed the size of the extent To determine the number of rows (the second number).

In addition, the compression unit size comparison module 150 can determine that the compression unit is underflow when the size of the compression unit is less than or equal to a predetermined ratio of the size of the extent. The predetermined ratio may be, for example, 95%. In the above example, when the size of the extent is 100 KB, and the size of the compression unit is 95 KB or less, the compression unit size comparison module 150 can determine that an underflow has occurred. The sizes and predetermined ratios of the extents and compression units described above are only exemplary, and the present invention is not limited thereto. When an underflow occurs, since there is a lot of empty space in one extent, the storage efficiency of the database may deteriorate. Therefore, when the underflow occurs, the compression unit size comparison module 150 determines that the number of the row number determination module 110 is smaller than the size of the compression unit generated by the compression unit generation module 130 To determine the appropriate number of rows (the second number).

According to one embodiment of the present invention, database server 100 may determine an appropriate number of rows to include in the compression unit. If too many rows are included in the compression unit and one compression unit exceeds the extent, the performance of the database for the query for data retrieval may be degraded. Also, if too few rows are included in the compression unit, and space is created in the extent storing one compression unit, the storage space efficiency of the database may be reduced. Also, each row included in each compression unit may contain different data, so that the appropriate number of appropriate rows to be included in the compression unit may not be constant. Thus, according to one embodiment of the present invention, the database server 100 may be able to minimize the performance degradation and to determine the appropriate size of the compression unit that can increase the storage space efficiency each time the compression unit is created. Also, according to an embodiment of the present invention, the database server 100 can reset the number of rows to be included in the compression unit so that the underflow or the overflow is not repeated, thereby reducing the computing power required for compression storage of the database have.

2 is an exemplary diagram illustrating a compression unit of a database according to one embodiment of the present invention.

The compression unit 200 may be stored in an extent that includes a plurality of data blocks. The compression unit 200 may include a plurality of data blocks and may include a header 210 of each data block, a compression unit header 230, and data 250. An extent is a collection of data blocks, which may be part of persistent storage 190 or memory 150.

The data block header 210 may include information for identifying data recorded in the corresponding data block, information related to the type of the data, and the like.

The compression unit header 230 includes information for decompressing and reading the data contained in the compression unit 230, information relating to the compression algorithm, information relating to the length of the columns included in the compression unit, And information for identifying the user.

The data 250 may be data of a particular column and row of a data table. The compression unit 200 may include data of all the columns of the row determined to increase the response performance to the query such as OLTP. For example, in a database where the number of columns is five and the number of rows is 100, if the number of rows included in the compression unit is five, the data included in the compression unit is low 1, column 1 to (1,1) 5, and column 5 (5, 5).

3 is a flowchart of a column-by-column compression method of a database according to an embodiment of the present invention.

The column-wise compression method of the database may be performed in a computing device that includes one or more processors and a main memory that stores instructions executable by the processor.

The row count determination module 110 may determine 310 the first number of rows to generate a compression unit for one or more columns located in a table of the database. The database is organized in a table, comprising one or more rows, and one row is composed of one or more columns. The row count determination module 110 may determine the number of rows for which the compression unit generation module 130 compresses the data contained in the first row of the one or more rows.

The compression unit generation module 130 may compress the determined first number of rows to generate a first compression unit (320). The compression unit generation module 130 may compress the first number of rows using any compression algorithm.

The compression unit size comparison module 150 may compare the size of the generated first compression unit with the size of the extent (330). The compression unit size comparison module 150 can determine that an overflow has occurred when the size of the first compression unit exceeds the size of the extent. In addition, the compression unit size comparison module 150 can determine that an underflow has occurred when the size of the first compression unit is less than or equal to a predetermined ratio of the extent size.

The row count determination module 110 may determine 340 the second number of rows to generate a compression unit for one or more columns based on the comparison result. The row number determination module 110 determines the number of rows (the second number of rows) to be included in the next compression unit when the comparison result of the compression unit size comparison module 150 results in an overflow, from the first number of rows It can be decided small. The row number determination module 110 also determines the number of rows (the second number of rows) to be included in the next compression unit when the underflow occurs as a result of the comparison of the compression unit size comparison module 150 to the first Can be determined to be larger than the number. At this time, the row number determination module 110 may determine the second number in a different manner depending on whether there is information on the number of rows in which an underflow has occurred or information on the number of rows in which an overflow occurred.

According to one embodiment of the present invention, database server 100 may determine an appropriate number of rows to include in the compression unit. If too many rows are included in the compression unit and one compression unit exceeds the extent, the performance of the database for the query for data retrieval may be degraded. Also, if too few rows are included in the compression unit, and space is created in the extent storing one compression unit, the storage space efficiency of the database may be reduced. Also, each row included in each compression unit may contain different data, so that the appropriate number of appropriate rows to be included in the compression unit may not be constant. Thus, according to one embodiment of the present invention, the database server 100 may be able to minimize the performance degradation and to determine the appropriate size of the compression unit that can increase the storage space efficiency each time the compression unit is created. Also, according to an embodiment of the present invention, the database server 100 can reset the number of rows to be included in the compression unit so that the underflow or the overflow is not repeated, thereby reducing the computing power required for compression storage of the database have.

Figure 4 illustrates a simplified, general schematic diagram of an exemplary computing environment in which embodiments of the present invention may be implemented.

Although the present invention has been described above generally in terms of computer-executable instructions that can be executed on one or more computers, those skilled in the art will appreciate that the present invention can be implemented as a combination of hardware and software in combination with other program modules.

Generally, program modules include routines, programs, components, data structures, etc. that perform particular tasks or implement particular abstract data types. It will also be appreciated by those skilled in the art that the methods of the present invention may be practiced with other computer systems, such as single-processor or multiprocessor computer systems, minicomputers, mainframe computers, as well as personal computers, handheld computing devices, microprocessor-based or programmable consumer electronics, And may operate in conjunction with one or more associated devices).

The described embodiments of the invention may also be practiced in distributed computing environments where certain tasks are performed by remote processing devices connected through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.

Computers typically include a variety of computer readable media. Any medium accessible by a computer may be a computer-readable medium, which may include volatile and non-volatile media, transitory and non-transitory media, removable and non-removable media, Removable media. By way of example, and not limitation, computer readable media may comprise computer storage media. Computer storage media includes volatile and nonvolatile media, both temporary and non-volatile media, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data, . Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital video disk (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, Or any other medium which can be accessed by a computer and used to store the desired information.

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There is shown an exemplary environment 1100 that implements various aspects of the present invention including a computer 1102 and includes a processing unit 1104, a system memory 1106 and a system bus 1108 do. The system bus 1108 couples system components, including but not limited to, system memory 1106 to the processing unit 1104. The processing unit 1104 may be any of a variety of commercially available processors. Dual processors and other multiprocessor architectures may also be used as the processing unit 1104.

The system bus 1108 may be any of several types of bus structures that may additionally be interconnected to a local bus using any of the memory bus, peripheral bus, and various commercial bus architectures. The system memory 1106 includes read only memory (ROM) 1110 and random access memory (RAM) The basic input / output system (BIOS) is stored in a non-volatile memory 1110, such as a ROM, EPROM, EEPROM or the like, which is a basic (non-volatile) memory device that aids in transferring information between components within the computer 1102 Routine. The RAM 1112 may also include a high speed RAM such as static RAM for caching data.

The computer 1102 may also be an internal hard disk drive (HDD) 1114 (e.g., EIDE, SATA) - this internal hard disk drive 1114 may also be configured for external use within a suitable chassis , A magnetic floppy disk drive (FDD) 1116 (e.g., for reading from or writing to a removable diskette 1118), and an optical disk drive 1120 (e.g., a CD-ROM For reading disc 1122 or reading from or writing to other high capacity optical media such as DVD). The hard disk drive 1114, magnetic disk drive 1116 and optical disk drive 1120 are connected to the system bus 1108 by a hard disk drive interface 1124, a magnetic disk drive interface 1126 and an optical drive interface 1128, respectively. . The interface 1124 for external drive implementation includes at least one or both of USB (Universal Serial Bus) and IEEE 1394 interface technologies.

These drives and their associated computer-readable media provide non-volatile storage of data, data structures, computer-executable instructions, and the like. In the case of computer 1102, the drives and media correspond to storing any data in a suitable digital format. While the above description of computer readable media refers to HDDs, removable magnetic disks, and removable optical media such as CDs or DVDs, those skilled in the art will appreciate that other types of storage devices, such as zip drives, magnetic cassettes, flash memory cards, Or the like may also be used in the exemplary operating environment and any such medium may include computer-executable instructions for carrying out the methods of the present invention.

A number of program modules may be stored in the drive and RAM 1112, including an operating system 1130, one or more application programs 1132, other program modules 1134, and program data 1136. All or a portion of the operating system, applications, modules, and / or data may also be cached in the RAM 1112. Those skilled in the art will appreciate that the invention may be implemented in a variety of commercially available operating systems or combinations of operating systems.

A user may enter commands and information into the computer 1102 via one or more wired / wireless input devices, such as a keyboard 1138 and a pointing device such as a mouse 1140. [ Other input devices (not shown) may include a microphone, an IR remote control, a joystick, a game pad, a stylus pen, a touch screen, and so on. These and other input devices are often connected to the processing unit 1104 via an input device interface 1142 that is coupled to the system bus 1108, but may be a parallel port, an IEEE 1394 serial port, a game port, a USB port, an IR interface, ≪ / RTI > and so forth.

A monitor 1144 or other type of display device is also connected to the system bus 1108 via an interface, such as a video adapter 1146, In addition to the monitor 1144, the computer typically includes other peripheral output devices (not shown) such as speakers, printers,

Computer 1102 may operate in a networked environment using logical connections to one or more remote computers, such as remote computer (s) 1148, via wired and / or wireless communication. The remote computer (s) 1148 can be a workstation, a server computer, a router, a personal computer, a portable computer, a microprocessor-based entertainment device, a peer device or other conventional network node, Includes a number of or all of the described elements, but for simplicity, only memory storage device 1150 is shown. The logical connections depicted include a wired / wireless connection to a local area network (LAN) 1152 and / or a larger network, e.g., a wide area network (WAN) These LAN and WAN networking environments are commonplace in offices and corporations and facilitate enterprise-wide computer networks such as intranets, all of which can be connected to computer networks worldwide, for example the Internet.

When used in a LAN networking environment, the computer 1102 is connected to the local network 1152 via a wired and / or wireless communication network interface or adapter 1156. [ The adapter 1156 may facilitate wired or wireless communication to the LAN 1152 and the LAN 1152 also includes a wireless access point installed therein to communicate with the wireless adapter 1156. [ When used in a WAN networking environment, the computer 1102 may include a modem 1158, or may be coupled to a communications server on the WAN 1154, or to other devices that establish communications over the WAN 1154, such as via the Internet. . A modem 1158, which may be an internal or external and a wired or wireless device, is coupled to the system bus 1108 via a serial port interface 1142. In a networked environment, program modules described for the computer 1102, or portions thereof, may be stored in the remote memory / storage device 1150. It will be appreciated that the network connections shown are exemplary and other means of establishing a communication link between the computers may be used.

The computer 1102 may be any wireless device or entity that is deployed and operable in wireless communication, such as a printer, a scanner, a desktop and / or portable computer, a portable data assistant (PDA) Any equipment or place, and communication with the telephone. This includes at least Wi-Fi and Bluetooth wireless technology. Thus, the communication may be a predefined structure, such as in a conventional network, or simply an ad hoc communication between at least two devices.

Wi-Fi (Wireless Fidelity) allows you to connect to the Internet without wires. Wi-Fi is a wireless technology such as a cell phone that allows such devices, e.g., computers, to transmit and receive data indoors and outdoors, i. E. Anywhere within the coverage area of a base station. Wi-Fi networks use a wireless technology called IEEE 802.11 (a, b, g, etc.) to provide a secure, reliable, and high-speed wireless connection. Wi-Fi can be used to connect computers to each other, the Internet, and a wired network (using IEEE 802.3 or Ethernet). The Wi-Fi network may operate in unlicensed 2.4 and 5 GHz wireless bands, for example, at 11 Mbps (802.11a) or 54 Mbps (802.11b) data rates, or in products containing both bands have.

Those of ordinary skill in the art will understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced in the above description may include voltages, currents, electromagnetic waves, magnetic fields or particles, Particles or particles, or any combination thereof.

Those skilled in the art will appreciate that the various illustrative logical blocks, modules, processors, means, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented or performed with a specific purpose, (Which may be referred to herein as "software") or a combination of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the design constraints imposed on the particular application and the overall system. Those skilled in the art may implement the described functionality in various ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The various embodiments presented herein may be implemented as a method, apparatus, or article of manufacture using standard programming and / or engineering techniques. The term "article of manufacture" includes a computer program, carrier, or media accessible from any computer-readable device. For example, the computer-readable medium can be a magnetic storage device (e.g., a hard disk, a floppy disk, a magnetic strip, etc.), an optical disk (e.g., CD, DVD, etc.), a smart card, But are not limited to, devices (e. G., EEPROM, cards, sticks, key drives, etc.). The various storage media presented herein also include one or more devices and / or other machine-readable media for storing information. The term "machine-readable medium" includes, but is not limited to, a wireless channel and various other media capable of storing, holding, and / or transferring instruction (s) and / or data.

It will be appreciated that the particular order or hierarchy of steps in the presented processes is an example of exemplary approaches. It will be appreciated that, based on design priorities, certain orders or hierarchies of steps in processes may be rearranged within the scope of the present invention. The appended method claims provide elements of the various steps in a sample order, but are not meant to be limited to the specific order or hierarchy presented.

The description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features presented herein.

Claims (12)

CLAIMS 1. A method of column-by-column compression of a database performed in a computing device comprising at least one processor and a main memory storing instructions executable by the processor,
Determining a first number of rows to generate a compression unit for one or more columns located in a table of the database;
Compressing the determined first number of rows to produce a first compression unit;
Comparing a size of the first compression unit with a size of an extent;
Determining that the first compression unit is overflow if the size of the first compression unit exceeds the size of the extent;
Determining whether there is information related to the number of rows underflow when it is determined that an overflow has occurred; And
Determining a second number of rows to generate a compression unit for one or more columns based on the comparison result;
/ RTI >
A method of column-by-column compression of a database.
The method according to claim 1,
Wherein the extent comprises a set of data blocks,
A method of column-by-column compression of a database.
The method according to claim 1,
If there is no information related to the number of rows in which the underflow occurred,
Determining a second number of rows to generate a compression unit for one or more columns based on the comparison result,
Determining a result value obtained by dividing the first number by a first predetermined number as the second number;
/ RTI >
A method of column-by-column compression of a database.
The method according to claim 1,
If there is information on the number of rows in which the underflow occurred,
Determining a second number of rows to generate a compression unit for one or more columns based on the comparison result,
Determining a result value obtained by subtracting a difference between the first number and the number of generated rows of the underflow by a second predetermined number in the first number as the second number;
/ RTI >
A method of column-by-column compression of a database.
CLAIMS 1. A method of column-by-column compression of a database performed in a computing device comprising at least one processor and a main memory storing instructions executable by the processor,
Determining a first number of rows to generate a compression unit for one or more columns located in a table of the database;
Compressing the determined first number of rows to produce a first compression unit;
Comparing a size of the first compression unit with a size of an extent;
Determining that the size of the first compression unit is underflow if the size of the first compression unit is less than or equal to a predetermined ratio of the size of the extent;
Determining whether there is information related to the number of rows where an overflow has occurred when it is determined that an underflow has occurred; And
Determining a second number of rows to generate a compression unit for one or more columns based on the comparison result;
/ RTI >
A method of column-by-column compression of a database.
6. The method of claim 5,
If there is no information related to the number of rows overflowing,
Determining a second number of rows to generate a compression unit for one or more columns based on the comparison result,
Determining a result value of the first number multiplied by a third predetermined number as the second number;
/ RTI >
A method of column-by-column compression of a database.
The method according to claim 6,
Wherein the third predetermined number is a number that is the maximum size the compression unit can have divided by the size of the first compression unit,
A method of column-by-column compression of a database.
6. The method of claim 5,
If there is information about the number of rows overflowed,
Determining a second number of rows to generate a compression unit for one or more columns based on the comparison result,
Determining the second number as a result of adding the first number and the number obtained by dividing the difference between the first number and the number of generated rows by a fourth predetermined number;
/ RTI >
A method of column-by-column compression of a database.
As a database server that provides column-by-column compression of a database,
The database server,
One or more processors; And
A memory for storing instructions executable on the one or more processors;
Lt; / RTI >
The one or more processors
Determine a first number of rows to generate a compression unit for one or more columns located in a table of the database and determine a second number of rows to generate a compression unit as the number of rows underflow Based on at least in part the information relating to the number of rows;
A compression unit generation module for compressing the determined first number of rows to generate a first compression unit; And
A compression unit size comparison module comparing the size of the first compression unit with the size of the extent and determining that the size of the first compression unit is overflow when the size of the first compression unit exceeds the size of the extent;
/ RTI >
A database server that provides column-by-column compression of the database.
As a database server that provides column-by-column compression of a database,
The database server,
One or more processors; And
A memory for storing instructions executable on the one or more processors;
Lt; / RTI >
Determining a first number of rows to generate a compression unit for one or more columns located in a table of the database and determining a second number of rows to generate a compression unit from the number of rows overflowed A row number determination module that determines a second number based at least in part on information related to the row number;
A compression unit generation module for compressing the determined first number of rows to generate a first compression unit; And
Comparing the size of the first compression unit with the size of the extent and comparing the compression unit size judging as underflow when the size of the first compression unit is equal to or less than a predetermined ratio of the size of the extent module;
/ RTI >
A database server that provides column-by-column compression of the database.
23. A computer program stored in a computer readable medium, comprising a plurality of instructions executed by one or more processors,
The computer program comprising:
Instructions for determining a first number of rows to generate a compression unit for one or more columns located in a table of a database;
Compressing the determined first number of rows to produce a first compression unit;
A command for comparing the size of the first compression unit with the size of the extent;
An instruction to determine an overflow if the size of the first compression unit exceeds the size of the extent as a result of the comparison;
An instruction for determining whether or not there is information related to the number of rows underflow when it is determined that an overflow has occurred; And
Instructions for determining a second number of rows to generate a compression unit for one or more columns based on the comparison result;
/ RTI >
A computer program stored on a computer readable medium.
A computer program stored in a computer readable storage medium, the computer program comprising a plurality of instructions executed by one or more processors,
The computer program comprising:
Instructions for determining a first number of rows to generate a compression unit for one or more columns located in a table of a database;
Compressing the determined first number of rows to produce a first compression unit;
A command for comparing the size of the first compression unit with the size of the extent;
An instruction to determine an underflow if the size of the first compression unit is equal to or less than a predetermined ratio of the size of the extent;
An instruction for determining whether or not there is information related to the number of rows in which an overflow has occurred when it is determined that an underflow has occurred; And
Instructions for determining a second number of rows to generate a compression unit for one or more columns based on the comparison result;
/ RTI >
A computer program stored on a computer readable storage medium.

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