Tracking intermediate changes in database data

Patent metadata

Field	Value
Publication number	US-10997162-B2
Application number	US-202016824676-A
Country	US
Kind code	B2
Filing date	Mar 19, 2020
Priority date	Nov 6, 2018
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

Systems, methods, and devices for tracking a series of changes to database data are disclosed. A method includes executing a transaction to modify data in a micro-partition of a table of a database by generating a new micro-partition that embodies the transaction. The method includes associating transaction data with the new micro-partition, wherein the transaction data comprises a timestamp when the transaction was fully executed, and further includes associating modification data with the new micro-partition that comprises an indication of one or more rows of the table that were modified by the transaction. The method includes joining the transaction data with the modification data to generate joined data and querying the joined data to determine a listing of intermediate modifications made to the table between a first timestamp and a second timestamp.

First claim

What is claimed is:

1. A method comprising:
providing a first micro-partition in a table at a first timestamp, the first micro-partition storing data;
receiving instructions for a transaction related to the stored data in the first micro-partition;
in response to the instructions, generating transaction data associated with the instructions and performing multiple modifications to the stored data to generate a second micro-partition and remove the first micro-partition from the table, the second micro-partition being generated at a second timestamp;
generating a delta table, the delta table storing final changes to the stored data in the second micro-partition at the second timestamp from the first micro-partition at the first timestamp;
generating modification data, the modification data tracking the modifications performed to the stored data between the first and second timestamps; and
joining the modification data with the transaction data to generate joined data, the joined data indicating intermediate changes to the stored data between the first and second timestamps.

2. The method of claim 1 , further comprising:
querying the joined data; and
generating a listing of the intermediate changes.

3. The method of claim 2 , wherein querying the joined data includes calculating tuple changes between each of a series of sequential micro-partition pairs between the first and second timestamps.

4. The method of claim 1 , further comprising:
performing multiple modifications to a row of a plurality of rows in the first micro-partition,
wherein the delta table stores an initial value of the row at the first timestamp and a final value of the row after performance of the multiple modifications to the row at the second timestamp, and
wherein the joined data indicates at least one intermediate change to the row between the initial and final values.

5. The method of claim 1 , wherein the delta table includes information indicating which rows have been modified, final values of rows that have been modified between the first and second timestamps, and an action type of the modification for each row modified.

6. The method of claim 1 , further comprising:
storing the transaction data in the second micro-partition as metadata, wherein the transaction data includes one or more of: an identity of an account that initiated the transaction, the second time stamp, a third timestamp when the transaction was requested, a fourth timestamp when execution of the transaction began, a listing of all rows that were modified by the transaction, and details of the modifications.

7. The method of claim 1 , further comprising:
storing the modification data in the second micro-partition as metadata, wherein the modification data includes a lineage of modifications made to the table.

8. The method of claim 1 , further comprising:
storing the transaction data and the modification data in the second micro-partition as metadata, wherein the metadata is stored in immutable storage.

9. The method of claim 1 , further comprising:
storing the transaction data and the modification data in the second micro-partition as metadata, wherein the metadata is stored in mutable storage.

10. A system comprising:
one or more processors of a machine; and
a memory storing instructions that, when executed by the one or more processors, cause the machine to perform operations comprising:
providing a first micro-partition in a table at a first timestamp, the first micro-partition storing data;
receiving instructions for a transaction related to the stored data in the first micro-partition;
in response to the instructions, generating transaction data associated with the instructions and performing multiple modifications to the stored data to generate a second micro-partition and remove the first micro-partition from the table, the second micro-partition being generated at a second timestamp;
generating a delta table, the delta table storing final changes to the stored data in the second micro-partition at the second timestamp from the first micro-partition at the first timestamp;
generating modification data, the modification data tracking the modifications performed to the stored data between the first and second timestamps; and
joining the modification data with the transaction data to generate joined data, the joined data indicating intermediate changes to the stored data between the first and second timestamps.

11. The system of claim 10 , the operations further comprising:
querying the joined data; and
generating a listing of the intermediate changes.

12. The system of claim 11 , wherein querying the joined data includes calculating tuple changes between each of a series of sequential micro-partition pairs between the first and second timestamps.

13. The system of claim 10 , the operations further comprising:
performing multiple modifications to a row of a plurality of rows in the first micro-partition,
wherein the delta table stores an initial value of the row at the first timestamp and a final value of the row after performance of the multiple modifications to the row at the second timestamp, and
wherein the joined data indicates at least one intermediate change to the row between the initial and final values.

14. The system of claim 10 , wherein the delta table includes information indicating which rows have been modified, final values of rows that have been modified between the first and second timestamps, and an action type of the modification for each row modified.

15. The system of claim 10 , the operations further comprising:
storing the transaction data in the second micro-partition as metadata, wherein the transaction data includes one or more of: an identity of an account that initiated the transaction, the second time stamp, a third timestamp when the transaction was requested, a fourth timestamp when execution of the transaction began, a listing of all rows that were modified by the transaction, and details of the modifications.

16. The system of claim 10 , the operations further comprising:
storing the modification data in the second micro-partition as metadata, wherein the modification data includes a lineage of modifications made to the table.

17. The system of claim 10 , the operations further comprising:
storing the transaction data and the modification data in the second micro-partition as metadata, wherein the metadata is stored in immutable storage.

18. The system of claim 10 , the operations further comprising:
storing the transaction data and the modification data in the second micro-partition as metadata, wherein the metadata is stored in mutable storage.

19. A non-transitory computer readable storage media storing instructions that, when executed by one or more processors, cause the one or more processors to:
providing a first micro-partition in a table at a first timestamp, the first micro-partition storing data;
receiving instructions for a transaction related to the stored data in the first micro-partition;
in response to the instructions, generating transaction data associated with the instructions and performing multiple modifications to the stored data to generate a second micro-partition and remove the first micro-partition from the table, the second micro-partition being generated at a second timestamp;
generating a delta table, the delta table storing final changes to the stored data in the second micro-partition at the second timestamp from the first micro-partition at the first timestamp;
generat

Assignees

• Snowflake Inc

Inventors

• Grabs Torsten
• Cseri Istvan
• Dageville Benoit

Classifications

• G06F16/2379 Primary

  Updates performed during online database operations; commit processing · CPC title

• G06F16/2282

  Tablespace storage structures; Management thereof · CPC title

• G06F16/24554

  Unary operations; Data partitioning operations · CPC title

• G06F16/2456

  Join operations · CPC title

• G06F16/219 Primary

  Managing data history or versioning (querying versioned data G06F16/2474; querying temporal data G06F16/2477) · CPC title