Query fault processing method and processing apparatus

Patent metadata

Field	Value
Publication number	US-10866866-B2
Application number	US-201816234095-A
Country	US
Kind code	B2
Filing date	Dec 27, 2018
Priority date	Jun 29, 2016
Publication date	Dec 15, 2020
Grant date	Dec 15, 2020

Abstract

A method for processing query fault, where a database server receives a query statement and generates a corresponding query plan tree including multiple layers of operators in a pipeline relationship, and each layer includes operation symbols having logical relationship with each other. The server executes the query statement according to the query plan tree, extracts intermediate status information of a faulty operator when a fault occurs in a process of executing the query statement, updates operation symbols of the faulty operator and a logical relationship among the operation symbols according to the query plan tree and the intermediate status information to obtain a reconstructed query plan tree, and continues to execute the query statement according to the reconstructed query plan tree after the fault is recovered.

First claim

What is claimed is:

1. A query fault processing method, comprising:
receiving a query statement;
generating a query plan tree corresponding to the query statement, the query plan tree comprising a plurality of layers of operators in a pipeline relationship, each layer comprising at least one operator, and each operator comprising operation symbols and a logical relationship among the operation symbols;
executing the query statement according to the query plan tree;
extracting intermediate status information of a faulty operator when a fault occurs in a process of executing the query statement, the intermediate status information being backed up at a backup time point before the fault occurs, the intermediate status information indicating an operation completed by the faulty operator and an operation uncompleted by the faulty operator at the backup time point, and the faulty operator being an operator executing the query statement when the fault occurs;
updating operation symbols of the faulty operator and a logical relationship among the operation symbols of the faulty operator according to the query plan tree and the intermediate status information of the faulty operator to obtain a reconstructed query plan tree; and
continuing to execute the query statement according to the reconstructed query plan tree after the fault is recovered to obtain a query result of the query statement.

2. The processing method of claim 1 , further comprising selectively backing up the intermediate status information of the faulty operator based on a backup cost of an intermediate status of the faulty operator.

3. The processing method of claim 2 , further comprising periodically performing selectively backing up the intermediate status information of the faulty operator based on the backup cost of the intermediate status of the faulty operator.

4. The processing method of claim 2 , wherein selectively backing up the intermediate status information of the faulty operator comprises backing up the intermediate status information of the faulty operator when a cost reduced by continuing to execute the faulty operator is greater than a sum of a cost required for backing up the operation completed by the faulty operator and a cost required for recovering the operation uncompleted by the faulty operator.

5. The processing method of claim 2 , wherein selectively backing up the intermediate status information of the faulty operator comprises backing up the intermediate status information of the faulty operator when a cost of continuing to execute the faulty operator is less than a sum of a cost required for backing up the operation completed by the faulty operator and a cost required for recovering the operation uncompleted by the faulty operator.

6. The processing method of claim 1 , wherein updating the operation symbols of the faulty operator and the logical relationship among the operation symbols of the faulty operator comprises:
recursively processing the uncompleted operation and the completed operation to obtain reconstructed information of the faulty operator, the reconstructed information comprising reconstructed operation symbols and a logical relationship among the reconstructed operation symbols; and
updating, according to the reconstructed information, original information in the faulty operator of the query plan tree corresponding to the reconstructed information to obtain the reconstructed query plan tree, the original information comprising original operation symbols and a logical relationship among the original operation symbols.

7. The processing method of claim 6 , wherein recursively processing the uncompleted operation and the completed operation to obtain the reconstructed information of the faulty operator comprises:
setting an end operation symbol for the completed operation; and
setting, in the uncompleted operation, a start operation symbol marking a start location of the uncompleted operation to obtain the reconstructed operation symbols and the logical relationship among the reconstructed operation symbols.

8. A database server, comprising:
a storage to store a computer executable program; and
at least one processor coupled to the storage, the computer executable program causing the at least one processor to be configured to:
receive a query statement;
generate a query plan tree corresponding to the query statement, the query plan tree comprising a plurality of layers of operators in a pipeline relationship, each layer comprising at least one operator, and each operator comprising operation symbols and a logical relationship among the operation symbols;
execute the query statement according to the query plan tree;
extract intermediate status information of a faulty operator when a fault occurs in a process of executing the query statement, the intermediate status information being backed up at a backup time point before the fault occurs, the intermediate status information indicating an operation completed by the faulty operator and an operation uncompleted by the faulty operator at the backup time point, and the faulty operator being an operator executing the query statement when the fault occurs;
update operation symbols of the faulty operator and a logical relationship among the operation symbols of the faulty operator according to the query plan tree and the intermediate status information of the faulty operator to obtain a reconstructed query plan tree; and
continue to execute the query statement according to the reconstructed query plan tree after the fault is recovered to obtain a query result of the query statement.

9. The database server of claim 8 , wherein the computer executable program further cause the at least one processor to be configured to selectively back up the intermediate status information of the faulty operator based on a backup cost of an intermediate status of the faulty operator.

10. The database server of claim 9 , wherein the computer executable program further cause the at least one processor to be configured to periodically perform selectively backing up the intermediate status information of the faulty operator based on the backup cost of the intermediate status of the faulty operator.

11. The database server of claim 9 , wherein the computer executable program further cause the at least one processor to be configured to back up the intermediate status information of the faulty operator when a cost reduced by continuing to execute the faulty operator is greater than a sum of a cost required for backing up the operation completed by the faulty operator and a cost required for recovering the operation uncompleted by the faulty operator.

12. The database server of claim 9 , wherein the computer executable program further cause the at least one processor to be configured to back up the intermediate status information of the faulty operator when a cost of continuing to execute the faulty operator is less than a sum of a cost required for backing up the operation completed by the faulty operator and a cost required for recovering the operation uncompleted by the faulty operator.

13. The database server of claim 8 , wherein the computer executable program further cause the at least one processor to be configured to:
recursively process the uncompleted operation and the completed operation to obtain reconstructed information of the faulty operator, the reconstructed information comprising reconstructed operation symbols and a logical relationship among the reconstructed operation symbols; and
update, according to the reconstructed information, original information in the faulty operator of the query plan tree corresponding

Assignees

• Huawei Tech Co Ltd

Inventors

• Zhu Jinwei
• Zhou Qingqing
• Zhou Pinggao

Classifications

• G06F16/24542 Primary

  Plan optimisation · CPC title

• G06F2201/84

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

• G06F16/2455

  Query execution · CPC title

• G06F11/1451

  by selection of backup contents · CPC title

• G06F11/1469 Primary

  Backup restoration techniques · CPC title