CHECK BLOB CHECKSUM

CHECK BLOB CHECKSUM checks for and displays columnstore blob file corruptions.

Syntax

CHECK BLOB CHECKSUM [WITH REPAIR[FORCE]];

Arguments

  • When high availability (HA) is enabled, the WITH REPAIR option will repair the corruption by replacing the corrupt blob with a valid copy (HA replica) from another partition. When HA is not enabled, the corruption cannot be repaired.

  • The WITH REPAIR FORCE option deletes the metadata for the corrupt blob. While this will allow the table to be queried, it will also result in data loss.

Example

This is a simple use showing how the output of CHECK BLOB CHECKSUM displays corruption in columnstore blob files.

CHECK BLOB CHECKSUM;
****
+---------+-----------+-------+----------+-------+---------------------+----------------------------------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------+
| node_id | Host      | Port  | Database | Table | Filename            | Reason                                                                                 | Repair operations                                                                                             |
+---------+-----------+-------+----------+-------+---------------------+----------------------------------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------+
| 2       | 127.0.0.1 | 10001 | db3      | rtab  | blobs/22/0/0/10_29  | File has incorrect checksum. Actual checksum 0x29072b55, expected checksum 0xe6ac67b6. | copy blob file from replica on '127.0.0.1':10000                                                              |
| 2       | 127.0.0.1 | 10001 | db3      | rtab  | blobs/22/0/0/10_58  | Missing file                                                                           | copy blob file from replica on '127.0.0.1':10000                                                              |
| 2       | 127.0.0.1 | 10001 | db3      | rtab  | blobs/22/0/0/10_88  | File has incorrect size. Actual size 49, expected size 44                              | Remove file (a copy of the file is avaliable on 127.0.0.1:10000, but its not valid.  Hit error 1017)          |
| 2       | 127.0.0.1 | 10001 | db3      | rtab  | blobs/22/0/0/10_112 | File has incorrect size. Actual size 51, expected size 46                              | copy blob file from replica on '127.0.0.1':10000                                                              |
| 2       | 127.0.0.1 | 10001 | db3      | rtab  | blobs/22/0/0/10_118 | File has incorrect size. Actual size 49, expected size 44                              | copy blob file from replica on '127.0.0.1':10000                                                              |
| 2       | 127.0.0.1 | 10001 | db3      | rtab  | blobs/22/0/0/10_191 | Missing file                                                                           | copy blob file from replica on '127.0.0.1':10000                                                              |
| 2       | 127.0.0.1 | 10001 | db3      | rtab  | blobs/22/0/0/10_203 | File has incorrect checksum. Actual checksum 0xf6aac90f, expected checksum 0x390185ec. | copy blob file from replica on '127.0.0.1':10000                                                              |
| 2       | 127.0.0.1 | 10001 | db3      | rtab  | blobs/22/0/0/10_208 | Missing file                                                                           | copy blob file from replica on '127.0.0.1':10000                                                              |
| 2       | 127.0.0.1 | 10001 | db3      | rtab  | blobs/22/0/0/10_214 | File has incorrect checksum. Actual checksum 0x205df634, expected checksum 0xdb081c6a. | copy blob file from replica on '127.0.0.1':10000                                                              |
| 2       | 127.0.0.1 | 10001 | db3      | rtab  | blobs/22/0/0/10_232 | File has incorrect checksum. Actual checksum 0x460d1e1a, expected checksum 0xbbab2e04. | Remove file (a copy of the file is avaliable on 127.0.0.1:10000, but its not valid.  Hit error 1017)          |
| 2       | 127.0.0.1 | 10001 | db3      | rtab  | blobs/22/0/0/10_238 | File has incorrect checksum. Actual checksum 0x31705cf0, expected checksum 0xca25b6ae. | copy blob file from replica on '127.0.0.1':10000                                                              |