Size as reported by BACKUP statement is wrong

[dveeden]

Bug Report

1. Minimal reproduce step (Required)

USE test;
create table t(id int primary key);
insert into t value(1);
BACKUP DATABASE test TO '/tmp/test_bck1';

2. What did you expect to see? (Required)

A backup with Size>0.

3. What did you see instead (Required)

 MySQL  127.0.0.1:4000 ssl  test  SQL > BACKUP DATABASE test TO '/tmp/test_bck1';
+----------------+------+--------------------+---------------------+---------------------+
| Destination    | Size | BackupTS           | Queue Time          | Execution Time      |
+----------------+------+--------------------+---------------------+---------------------+
| /tmp/test_bck1 |    0 | 428551715438198786 | 2021-10-21 07:44:17 | 2021-10-21 07:44:17 |
+----------------+------+--------------------+---------------------+---------------------+
1 row in set (0.0249 sec)

 MySQL  127.0.0.1:4000 ssl  test  SQL > SELECT DATA_LENGTH+INDEX_LENGTH FROM information_schema.tables WHERE table_schema='test';
+--------------------------+
| DATA_LENGTH+INDEX_LENGTH |
+--------------------------+
|                     8707 |
+--------------------------+
1 row in set (0.0039 sec)
 MySQL  127.0.0.1:4000 ssl  test  SQL > \! du -sh /tmp/test_bck1
16K	/tmp/test_bck1
 MySQL  127.0.0.1:4000 ssl  test  SQL > \! ls -lh /tmp/test_bck1
total 16K
-rw-rw-r--. 1 dvaneeden dvaneeden 5.0K Oct 21 07:44 1_2_26_748765eba3cf49effbf31ce0d4d6b8c7a69fbc3ccc87853d158e4de5b8d1c4b3_1634795057078_write.sst
-rw-r--r--. 1 dvaneeden dvaneeden   78 Oct 21 07:44 backup.lock
-rw-r--r--. 1 dvaneeden dvaneeden 2.6K Oct 21 07:44 backupmeta

4. What is your TiDB version? (Required)

*************************** 1. row ***************************
tidb_version(): Release Version: v5.2.1
Edition: Community
Git Commit Hash: cd8fb24c5f7ebd9d479ed228bb41848bd5e97445
Git Branch: heads/refs/tags/v5.2.1
UTC Build Time: 2021-09-08 02:32:56
GoVersion: go1.16.4
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false
1 row in set (0.0006 sec)

[dveeden]

/component br

[3pointer]

I believe #27508 fix it.
Thanks for report. I'm going to close this issue.

[github-actions]

Please check whether the issue should be labeled with 'affects-x.y' or 'fixes-x.y.z', and then remove 'needs-more-info' label.

[dveeden]

This indeed looks fixed. However the size seems to be wrong. Looks like the size of the backupmeta isn't included in the total. However with any real backup a difference of 2.1K is negligible.

 MySQL  127.0.0.1:4000 ssl  test  SQL > USE test;
Default schema set to `test`.
Fetching table and column names from `test` for auto-completion... Press ^C to stop.
 MySQL  127.0.0.1:4000 ssl  test  SQL > create table t(id int primary key);
Query OK, 0 rows affected (0.1531 sec)
 MySQL  127.0.0.1:4000 ssl  test  SQL > insert into t value(1);
Query OK, 1 row affected (0.0108 sec)
 MySQL  127.0.0.1:4000 ssl  test  SQL > BACKUP DATABASE test TO '/tmp/test_bck1';
+----------------+------+--------------------+---------------------+---------------------+
| Destination    | Size | BackupTS           | Queue Time          | Execution Time      |
+----------------+------+--------------------+---------------------+---------------------+
| /tmp/test_bck1 | 1423 | 428711730816483330 | 2021-10-28 09:17:47 | 2021-10-28 09:17:47 |
+----------------+------+--------------------+---------------------+---------------------+
1 row in set (0.0355 sec)
 MySQL  127.0.0.1:4000 ssl  test  SQL > \! du -sh /tmp/test_bck1
12K	/tmp/test_bck1
 MySQL  127.0.0.1:4000 ssl  test  SQL > \! ls -lh /tmp/test_bck1
total 12K
-rw-rw-r--. 1 dvaneeden dvaneeden 1.4K Oct 28 09:17 1_2_28_2550d727ffe3e408af41f541b134d5e064440c25988bbecfb665933d1195a45d_1635405467328_write.sst
-rw-r--r--. 1 dvaneeden dvaneeden   78 Oct 28 09:17 backup.lock
-rw-r--r--. 1 dvaneeden dvaneeden 2.1K Oct 28 09:17 backupmeta
 MySQL  127.0.0.1:4000 ssl  test  SQL > SELECT tidb_version()\G
*************************** 1. row ***************************
tidb_version(): Release Version: v5.3.0-alpha-1229-g9a780a213
Edition: Community
Git Commit Hash: 9a780a21380cde952115e3f8e9a6b0d2fc4ba5b9
Git Branch: master
UTC Build Time: 2021-10-27 11:32:52
GoVersion: go1.16.4
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false
1 row in set (0.0011 sec)