Why is WRITTEN_BYTES equal to 0 after importing data?

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1

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This topic has been translated from a Chinese forum by GPT and might contain errors.

Original topic: 导入数据后 WRITTEN_BYTES 等于 0 是什么原因？

| username: KaiNiao

[TiDB Usage Environment] Test
[TiDB Version] 6.5.0
[Reproduction Path] sysbench import test data
[Encountered Problem: Problem Phenomenon and Impact] WRITTEN_BYTES=0, APPROXIMATE_SIZE=95M, what is the reason?
[Resource Configuration]
[Attachment: Screenshot/Log/Monitoring]

Query the size of the specified region_id in the TIKV_REGION_STATUS table, the results are as follows:

MySQL [information_schema]> SELECT * FROM tikv_region_status where region_id=188 \G
*************************** 1. row ***************************
REGION_ID: 188
START_KEY: 7480000000000000FF525F698000000000FF0000010380000000FF0041789603800000FF000002BBD8000000FD
END_KEY: 7480000000000000FF525F728000000000FF0647410000000000FA
TABLE_ID: 82
DB_NAME: sbtest
TABLE_NAME: sbtest1
IS_INDEX: 1
INDEX_ID: 1
INDEX_NAME: k_1
EPOCH_CONF_VER: 5
EPOCH_VERSION: 89
WRITTEN_BYTES: 0
READ_BYTES: 0
APPROXIMATE_SIZE: 95
APPROXIMATE_KEYS: 410870
REPLICATIONSTATUS_STATE: NULL
REPLICATIONSTATUS_STATEID: NULL
*************************** 2. row ***************************
REGION_ID: 188
START_KEY: 7480000000000000FF525F698000000000FF0000010380000000FF0041789603800000FF000002BBD8000000FD
END_KEY: 7480000000000000FF525F728000000000FF0647410000000000FA
TABLE_ID: 82
DB_NAME: sbtest
TABLE_NAME: sbtest1
IS_INDEX: 0
INDEX_ID: NULL
INDEX_NAME: NULL
EPOCH_CONF_VER: 5
EPOCH_VERSION: 89
WRITTEN_BYTES: 0
READ_BYTES: 0
APPROXIMATE_SIZE: 95
APPROXIMATE_KEYS: 410870
REPLICATIONSTATUS_STATE: NULL
REPLICATIONSTATUS_STATEID: NULL
2 rows in set (0.01 sec)

Question:

The definition of WRITTEN_BYTES is: the amount of data (bytes) written to the Region.

But why is WRITTEN_BYTES=0 right after importing?

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| username: h5n1 | Original post link

This should only have a value when there are read and write operations, you can give it a try.

3
| username: WalterWj | Original post link

This should be the amount of data imported by the region over a period of time, and it should be gone after a while…

4
| username: KaiNiao | Original post link

Okay, thank you, I’ll try again.

5
| username: KaiNiao | Original post link

Okay, thank you, I will verify it again.