Data loading tool

Patent metadata

Field	Value
Publication number	US-2016188418-A1
Application number	US-201514851184-A
Country	US
Kind code	A1
Filing date	Sep 11, 2015
Priority date	Oct 19, 2012
Publication date	Jun 30, 2016
Grant date	—

Abstract

In an exemplary embodiment of this disclosure, a method for loading data from a backup image of a database includes selecting a subset statement defining a subset of the data in the database. Tables of the database are identified based on metadata of the database. A target database is written having the structure but not the data of the identified tables. One or more table statements are constructed, by a computer processor, defining a subset of each identified table based on the subset statement. Selected data is unloaded from a backup image into the target database using respective table statements as filters.

First claim

What is claimed is:

1 . A method for loading selective data from a database, the database comprising a plurality of tables that are structured in a particular topology and the database contains data in the tables, the method comprising:
receiving, by a processor, a request to access a subset of the data in the database; in response, writing, by the processor, an empty target database having the topology of the tables in the database; identifying, by the processor, a subset of the tables referenced in the subset of the data corresponding to the request; determining, by the processor, an unload order to unload the subset of the data from the tables, wherein the unload order facilitates unloading the data within a predetermined duration; and unloading, by the processor, the subset of the data from a backup image of the database into the target database in the determined unload order, wherein the processor unloads the subset of the data in form of rows of the tables.

2 . The method of claim 1 , further comprising:
constructing, by the processor, one or more table statements defining a subset of each table in the database based on the subset of the data requested; and unloading the subset of the data using respective table statements as filters.

3 . The method of claim 1 , further comprising:
receiving, by the processor, a selection of the backup image to unload the subset of the data from; and selecting, by the processor, the backup image of the database according to the selection.

4 . The method of claim 1 further comprising, identifying, by the processor, the topology of the tables in the database based on metadata of the database.

5 . The method according to claim 1 , wherein the unload order unloads the tables in the database that are associated with respective filter predicates specified in the request before other tables in the database.

6 . The method according to claim 1 , wherein the unload order processes tables that are in a single file of the backup image in a single scan of the backup image.

7 . The method according to claim 1 , wherein determining the unload order comprises:
identifying tables in the database that have the lowest expected number of rows to be unloaded; and ordering the tables with the lowest expected number of rows to be unloaded first.

8 . The method according to claim 1 , further comprising:
receiving, by the processor, database constraints for the target database; and configuring, by the processor, the target database according to the database constraints.

9 . A computer program product comprising computer readable storage medium having computer executable instructions embodied thereon, the computer readable storage medium comprises instructions to:
receive a data selection query that selects a subset of data in a source database, the source database comprising the data structured in rows of tables; identify a topology of the tables in the source database based on metadata of the source database; create an empty target database according to the topology of the source database; determine a first row of a first table in the source database being referenced by the data selection query; and unload contents of the first row of the first table from a backup image of the source database to a first row of a first table in the target database.

10 . The computer program product of claim 9 , wherein the non-transitory computer readable storage medium further comprises instructions to:
receive a selection of a version of the backup image to use for copying contents; and use a latest version of the backup image in absence of the selection.

11 . The computer program product of claim 9 , wherein the computer readable storage medium further comprises instructions to:
determine a second row of a second table in the source database being referenced by the data selection query; and construct a table statement that identifies the first row and the second row; and determine an unload order to unload the contents from the backup image of the source database based on the table statement; and unload contents of the first row from the first table and the second row from the second table according to the unload order.

12 . The computer program product of claim 11 , wherein the unload order facilitates the contents to be unloaded within a predetermined duration.

13 . The computer program product of claim 12 , wherein the unload order unloads the contents of the first table before the second table in response to the data selection query specifying a filter predicate for the first table.

14 . The computer program product of claim 12 , wherein the unload order unloads the contents of the first table before the second table in response to the first table containing a lower number of rows than the second table.

15 . The computer program product of claim 12 , wherein the computer readable storage medium further comprises instructions to unload the contents of the first table and the second table in a single scan of the backup image in response to the first table and the second table being in a single file of the backup image.

16 . A system for unloading data from a backup image of a database, the system comprising:
a source database comprising data structured as rows of tables, the tables related to each other according to a predetermined topology; a database repository comprising a plurality of backup images of the source database, wherein a backup image stores the data in files; a server configured to:
receive a data selection query to access a subset of data in the source database;
create an empty target database according to the topology of the source database;
determine a subset of the tables in the source database referenced by the data selection query; and
unload contents of the subset of the tables from the backup image of the source database to corresponding rows of the tables in the target database.

17 . The system of claim 16 , wherein the server is further configured to identify the predetermined topology of the source database based on metadata of the source database.

18 . The system of claim 16 , wherein the server is further configured to construct one or more table statements defining a subset of each table in the subset of tables based on the data selection query; and
determine an unload order to unload the contents of the source data according to the table statements; and unload the contents from the backup image into the target database using respective table statements as filters in the determined unload order.

19 . The system of claim 18 , wherein the server is further configured to:
receive, prior to determining the unload order:
a modification to the data selection query; and
a modification to a set of database constraints associated with the target database; and
in response, determine the unload order according to a modified data selection query and a modified target database.

20 . The system of claim 18 , wherein the unload order unloads the contents from the backup image to the target database within a predetermined duration.

Assignees

• IBM

Inventors

• Abed Sami
• Clifford Austin
• Emanowicz Konrad
• Jenkins Gareth

Classifications

• G06F11/1451 Primary

  by selection of backup contents · CPC title

• G06F16/21 Primary

  Design, administration or maintenance of databases · CPC title

• G06F2201/84

  Using snapshots, i.e. a logical point-in-time copy of the data · CPC title

• G06F16/245

  Query processing · CPC title

• G06F16/2282

  Tablespace storage structures; Management thereof · CPC title