KR101690282B1 - Method and apparatus of converting feature of tablespace - Google Patents

Abstract

A method and apparatus for changing a table space attribute are disclosed. The database system locks the non-logging tablespace located in the memory, creates storage space for the non-logging tablespace on the disk, writes the data of the non-logging tablespace to the storage space created on the disk Change the attributes of the non-logging tablespace from non-logging to logging and release the lock.

Description

METHOD AND APPARATUS FOR CHANGING TEXT SPACE ATTRIBUTES [0002]

The present invention relates to a table space of a database system, and more particularly, to a method and apparatus for changing attributes of a table space from no-logging to logging or vice versa.

Generally, when a database loads data into a table space including at least one page, transaction logging is performed for data recovery and the like. Here, the term "transaction logging" refers to the recording of a change in the data stored in the database before the change (addition, deletion, update, etc.) is made. In the following, transaction logging or logging is used in combination as long as there is no confusion.

If you are loading large amounts of data into the database, the logging process will take a long time. In particular, in the case of data loading for initial construction of a database, a very large amount of data is loaded, which takes a long time to construct a system.

Patent Publication No. 2008-0044480

SUMMARY OF THE INVENTION The present invention provides a method and apparatus for changing a table space to a logging state so as to avoid problems such as data recovery after loading a large amount of data into a table space in a non- There is.

According to an aspect of the present invention, there is provided a method for changing a table space attribute, the method comprising: performing a lock of a non-logging table space located in a memory; Creating storage space for the non-logging tablespace on the disk; Recording data of the non-logging tablespace in a storage space created on the disk; Changing an attribute of the non-logging tablespace from non-logging to logging; And releasing the lock.

According to another aspect of the present invention, there is provided a method for changing a table space attribute, the method comprising: a first attribute for loading data into a table space located in a memory without transaction logging; Selecting one of the second attributes to load; Loading the data according to the selected attribute; And storing the data of the table space in the storage space created in the disk in the locked state, changing the meta information of the table space to the second attribute if there is a request to change from the first attribute to the second attribute, And releasing the lock.

According to an aspect of the present invention, there is provided a database system comprising: a first memory including a tablespace whose attribute is logging or non-logging; A second memory including a meta tablespace for storing attributes of a table space implemented in the first memory as meta information; Wherein the attribute of the table space stored in the first memory corresponds to the meta information of the meta tablespace stored in the second memory, A storage space for the table space of the first memory is created on the disk and a table space of the first memory is created when the attribute stored in the meta information of the meta tablespace is changed from non-logging to logging, Is stored in the storage space of the disk in the locked state.

According to another aspect of the present invention, there is provided a database system including a first attribute for loading data together with transaction logging, and a second attribute for loading data without transaction logging, An attribute storage unit for storing the attributes as spaces; A data loading unit loading data into the table space according to the selected attribute; Creating a storage space for the table space on the disk and storing the data of the table space in a storage space of the disk in a locked state when the second attribute is to be changed to the first attribute, And an attribute changing unit for changing the meta information of the meta tablespace storing the attributes of the space from the second attribute to the first attribute.

According to the present invention, loading time can be saved by omitting the logging process when a large amount of data needs to be loaded into the table space as in the initial stage of database construction. Also, the non-logging state of the tablespace stored in the memory can be switched to the logging state to prevent problems such as data recovery later. If you want to change the non-logging table space to the logging table space, you can change only the meta information. Therefore, you can create a separate logging table space in memory, or use the non-logging table space without changing the internal data structure. .

Brief Description of Drawings Fig. 1 is a diagram showing a configuration of an example of a database system for performing a method of changing a table space attribute according to the present invention; Fig.
FIG. 2 is a flow chart showing an example of a method of changing a table space attribute according to the present invention;
FIG. 3 illustrates an example of a meta tablespace and a non-logging tablespace according to the present invention,
FIG. 4 is a diagram showing a configuration of an example of a database system for performing a change of a table space attribute according to the present invention.

Hereinafter, a method and apparatus for changing a table space attribute according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing a configuration of an example of a database system for performing a method of changing a table space attribute according to the present invention.

Referring to FIG. 1, a database system includes a memory 100 and a disk 130. Of course, the database system may include various configurations such as a user interface for inputting and receiving commands from a user, a central processing unit for controlling a memory or a disk, and executing various commands. However, in order to facilitate understanding of the present invention, FIG. 1 shows and describes mainly the configuration related to the features of the present invention.

The memory 100 includes a first memory 110 including a meta tablespace 112 and a second memory 120 including a table space 122. [ The first memory 110 and the second memory 120 may be physically or logically separated from each other.

The meta tablespace 112 stores meta information about the table spaces 122. [ As an example of meta information, there is attribute information indicating whether the table space is in a non-logging state or a logging state.

The table space 122 becomes a non-logging table space or a logging table space according to the meta information of the meta tablespace 112. Here, the non-logging table space is called a volatile table space, and the logging table space is also called a non-volatile table space.

The disk 130 includes a meta tablespace 132 and a logging tablespace 134. Here, the disk 130 is not limited to a hard disk and the like, and includes all the mass storage devices such as a solid-state disk (SSD) or a storage medium using a semiconductor memory. The meta information is stored and updated together in the meta tablespace 112 of the memory and the meta tablespace 132 of the disk.

The table space 134 of the disk is maintained in the logging state and is not maintained in the non-logging state. For example, in the case of a logging state, data is stored (140) with transaction logging in the table space 122 of the memory and the table space 134 of the disk. On the other hand, in the non-logging state, the data is stored in the table space 122 of the memory without transaction logging, and no data is stored in the disk 130. [

In order to reduce the data loading time, it is necessary to change the tablespace from the non-logging state to the logging state in order to recover the data, since it is difficult to recover the data loss due to the failure when the table space is operated in the non-logging state . Conversely, to reduce data loading time, it is necessary to change the attributes of the tablespace from logging to non-logging.

FIG. 2 is a flowchart illustrating an example of a method of changing a table space attribute according to the present invention.

Referring to FIG. 2, the database system locks a non-logging table space in order to change the attribute of the non-logging tablespace located in the memory (S200).

The database system then creates space for storage of non-logging tablespaces on disk. For example, the database system creates a disk data file to store data for a non-logging tablespace. The size of the storage space created on the disk may be equal to or greater than the size of the non-logging tablespace.

The database system writes the data of the non-logging tablespace of the memory in a storage space created in the disk (S220). At this time, the database system writes the entire data of the non-logging tablespace to the disk at a time, so that the disk system can perform a write operation to the disk sequentially. For example, the database system may sequentially write all data of the non-logging tablespace to disk by referring to the list of page control headers of the table space.

For non-logging tablespaces, the log sequence number is not required because logging is not performed, but the log sequence number is needed for logging tablespace space. The database system sets the log sequence number for the page of data stored in the storage space created on the disk to the empty value or the latest log sequence number.

The database system changes the meta information of the non-logging tablespace when all the data of the non-logging tablespace of the memory is stored on the disk (S230). In other words, the database system changes the non-logging (i.e., volatile) state to the logging state (i.e., non-volatile) attribute information currently stored in the meta information of the non-logging tablespace. At this time, the identification information (ID) of the table space is kept the same as the previous one, not the new logging table space is newly created in the memory but the data structure of the existing non-logging tablespace is maintained. In other words, even if the non-logging tablespace is changed to a logging-tablespace, the memory pointer of each page and record is not changed, so you do not need to change the pointer to individual records recorded in the index.

The database system releases the lock state after changing the attribute of the table space (S240). The database system then loads the data into the memory and disk tablespaces, along with the transaction logging process.

FIG. 3 is a diagram illustrating an example of a meta tablespace and a non-logging table space according to the present invention.

Referring to FIGS. 1 and 3 together, the meta tablespace 300 stored in the first memory 110 includes a table space header 310 indicating a non-logging tablespace. Although the present embodiment shows only one non-logging tablespace for convenience of explanation, the meta tablespace 300 may include information on a plurality of non-logging and logging state tablespaces.

The non-logging table space 350 stored in the second memory 120 is composed of a data page 360 and an index 370 and may not include a log sequence number for each page because it does not perform a logging process . If it is a logging-table space, it includes the log sequence number per page.

When a tablespace is changed from non-logging to logging, the meta tablespace meta information that points to the table space is changed. However, the pointer to the individual records recorded in the index 370 is not changed.

FIG. 4 is a diagram showing a configuration of an example of a database system for performing a change of a table space attribute according to the present invention.

Referring to FIG. 4, the database system 400 includes an attribute storage unit 410, a data loading unit 420, and an attribute changing unit 430.

The attribute storage unit 410 stores whether attributes of at least one or more tablespaces implemented in the memory are in a logging state or a non-logging state. The attribute storage unit 410 may store and manage meta information indicating a property of the table space in a memory area logically or physically distinguished from a memory in which the table space is stored. For example, the attribute storage unit 410 may store a meta tablespace including meta information in a memory and a disk.

The data loading unit 420 controls the data loading process of the table space according to the attributes stored in the attribute storage unit 410. [ For example, when the attribute of the table space is stored in the attribute storage unit 410 in a non-logging state, the data loading unit 420 loads data without performing a separate logging process. On the other hand, if the attribute of the table space is stored in the attribute storage unit 410 in the logging state, the data loading unit 420 loads the data along with the logging process to the memory and the disk.

The attribute changing unit 430 changes the attribute of the table space from non-logging to vice versa, or vice versa, according to a user's request or predetermined condition. For example, when the attribute of the table space is to be changed from the non-logging state to the logging state, the attribute changing unit 430 locks the non-logging table space stored in the memory and creates a data storage space on the disk And stores the data of the non-logging tablespace in the storage space of the disk, and changes the attributes of the tablespace stored in the attribute storage unit from non-logging to logging. Then, the property changing unit 430 unlocks the non-logging tablespace.

The present invention can also be embodied as computer-readable codes on a computer-readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. Examples of the computer-readable recording medium include various types of ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like. The computer-readable recording medium may also be distributed over a networked computer system so that computer readable code can be stored and executed in a distributed manner.

The present invention has been described with reference to the preferred embodiments. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

Claims (13)

delete delete delete delete In a method for changing table space attributes in a database system,
The database system comprises:
Selecting one of a first attribute for loading data in a tablespace located in the memory without transaction logging and a second property for loading data in the table space with transaction logging;
Loading data into the table space according to the selected attributes; And
Storing the data of the table space in a storage space created in a disk in a locked state, changing meta information of the table space to a second attribute if there is a request to change from the first attribute to the second attribute, And releasing the table space attribute from the table space. A first memory including a tablespace whose attributes are logging or non-logging; And
A second memory including a meta tablespace for storing an attribute of a table space implemented in the first memory as meta information;
And a disk including a storage space for a table space in which an attribute stored in the meta tablespace is logging,
The attribute of the table space stored in the first memory is changed according to the meta information of the meta tablespace stored in the second memory,
A storage space for a table space of the first memory is created on the disk when the attribute stored in the meta information of the meta tablespace is changed from non-logging to logging, and the data of the table space of the first memory is And is stored in a storage space of the disk in a locked state. The method according to claim 6,
Wherein the first memory and the second memory are physically or logically separated memories. The method according to claim 6,
Wherein a log sequence number recorded in a page of a table space whose attribute is changed from non-logging to logging is a latest log sequence number or an empty value. delete delete delete delete A computer-readable recording medium storing a program for performing the method according to claim 5.

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