Data pruning based on metadata

Patent metadata

Field	Value
Publication number	US-2020089655-A1
Application number	US-201916688888-A
Country	US
Kind code	A1
Filing date	Nov 19, 2019
Priority date	Jul 14, 2016
Publication date	Mar 19, 2020
Grant date	—

Abstract

A system and method for pruning data based on metadata. The method may include receiving a query comprising a plurality of predicates and identifying one or more applicable files comprising database data satisfying at least one of the plurality of predicates. The identifying the one or more applicable files including reading metadata stored in a metadata. store that is separate from the database data. The method further includes pruning inapplicable files comprising database data that does not satisfy at least one of the plurality of predicates to create a reduced set of files and reading the reduced set of files to execute the query.

First claim

What is claimed is:

1 . A system comprising:
a metadata store to store metadata; and a processor, operatively coupled with the metadata store, to:
receive a query comprising a plurality of predicates;
identify one or more applicable files comprising database data satisfying at least one of the plurality of predicates, wherein identifying the one or more applicable files comprises reading the metadata stored in the metadata store that is separate from the database data;
prune inapplicable files comprising database data that does not satisfy at least one of the plurality of predicates to create a reduced set of files; and
read the reduced set of files to execute the query.

2 . The system of claim 1 , wherein the processor to identify based on the metadata store one or more predicates of the query that do not fully match any file comprising database data.

3 . The system of claim 2 , the processor to remove from the query the one or more predicates that do not fully match any file comprising database data to create a modified query.

4 . The system of claim 1 , wherein the processor to store the database data in a plurality of files, wherein each file of the plurality of files comprises a discrete selection of the database data.

5 . The system of claim 4 , wherein the processor further to:
generate a metadata file comprising information about a discrete selection of database data stored in a file: and store the metadata file in the metadata store separate from the discrete selection of the database data.

6 . The system of claim 1 , wherein to prune the inapplicable files, the processor to:
identify the inapplicable files without accessing the inapplicable files; and remove from consideration the inapplicable files such that the inapplicable files are not read during execution of the query.

7 . The system of claim 6 , wherein to identify the inapplicable files, the processor to:
read metadata pertaining to each of the inapplicable files, the metadata stored in the metadata store; or identify all other files comprising database data not including the applicable files identified by the identifying of the one or more applicable files.

8 . The system of claim 1 , wherein to read the metadata, the processor to:
determine, based on the metadata, a range of values of database data stored in a certain file; and determine whether any data within the range of values of database data stored in the certain file satisfies at least one of the plurality of predicates.

9 . The system of claim 8 , wherein to identify the one or more applicable files, the processor to identify the certain file as being an applicable file in response to a determination that some data within the range of values stored in the certain file satisfies at least one of the plurality of predicates.

10 . The system of claim 1 , wherein the processor further to identify at least one applicable column within each of the one or more applicable files that comprises database data satisfying at least one of the plurality of predicates.

11 . The system of claim 1 , wherein the processor further to execute the query.

12 . The system of claim 1 , wherein the processor further to:
identify, based on the metadata, one or more predicates of the query that do not fully match any file comprising database data; and remove from the query the one or more predicates that do not fully match any file comprising database data to create a modified query.

13 . A method comprising:
receiving a query comprising a plurality of predicates; identifying, by a processor, one or more applicable files comprising database data satisfying at least one of the plurality of predicates, wherein the identifying the one or more applicable files comprises reading metadata stored in a metadata store that is separate from the database data; pruning inapplicable files comprising database data that does not satisfy at least one of the plurality of predicates to create a reduced set of files; and reading the reduced set of files to execute the query.

14 . The method of claim 13 , further comprising identifying, based on the metadata, one or more predicates of the query that do not fully match any file comprising database data.

15 . The method of claim 14 , further comprising removing from the query the one or more predicates that do not fully match any file comprising database data to create a modified query.

16 . The method of claim 12 , further comprising storing the database data in a plurality of files, wherein each file of the plurality of files comprises a discrete selection of the database data.

17 . The method of claim 12 , wherein pruning the inapplicable files comprises:
identifying the inapplicable files without accessing the inapplicable files; and removing from consideration the inapplicable files such that the inapplicable files are not read during execution of the query.

18 . The method of claim 17 , reading the metadata comprises:
determining, based on the metadata, a range of values of database data stored in a certain file; and determining whether any data within the range of values of database data stored in the certain file satisfies at least one of the plurality of predicates.

19 . The method of claim 18 , wherein identifying the one or more applicable files comprises identifying the certain file as being an applicable file in response to a determination that some data within the range of values stored in the certain file satisfies at least one of the plurality of predicates

20 . The method of claim 12 , further comprising executing the query.

21 . The method of claim 12 , further comprising:
generating a metadata file comprising information about a discrete selection of database data stored in a file; and storing the metadata file in the metadata store separate from the discrete selection of the database data.

22 . The method of claim 12 , further comprising identifying at least one applicable column within each of the one or more applicable files that comprises database data satisfying at least one of the plurality of predicates.

23 . A non-transitory computer readable storage media, programmable to execute instructions that, when executed by a processor, cause the processor to:
receive a query comprising a plurality of predicates; identify one or more applicable files comprising database data satisfying at least one of the plurality of predicates, wherein to identify the one or more applicable files, the processor to read metadata stored in a metadata store that is separate from the database data; prune, by the processor, inapplicable files comprising database data that does not satisfy at least one of the plurality of predicates to create a reduced set of files; and read the reduced set of files to execute the query.

24 . The non-transitory computer readable storage media of claim 23 , the instructions further to cause the processor to:
identify, based on the metadata, one or more predicates of the query that do not fully match any file comprising database data; and remove from the query the one or more predicates that do not fully match any file comprising database data to create a modified query.

25 . The non-transitory computer readable storage media of claim 23 , the instructions further to cause the processor to store the database data in a plurality of files, wherein each file of th

Assignees

• Snowflake Inc

Inventors

• Zukowski Marcin
• Dageville Benoit
• Cruanes Thierry
• Motivala Ashish

Classifications

• G06F16/9535

  Search customisation based on user profiles and personalisation · CPC title

• G06F16/162 Primary

  Delete operations (erasing in storage systems G06F3/0652) · CPC title

• G06F16/24544

  Join order optimisation · CPC title

• G06F16/22

  Indexing; Data structures therefor; Storage structures · CPC title

• G06F16/215

  Improving data quality; Data cleansing, e.g. de-duplication, removing invalid entries or correcting typographical errors · CPC title