Details
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Technical task
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Status: Closed (View Workflow)
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Critical
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Resolution: Fixed
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10.7(EOL), 10.8(EOL)
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None
Description
Implement binary changes enumerated in MDEV-26946
Proposed texts as per MDEV-26946:
$ ./bin/mysqldump --help --verbose | grep -A3 -m1 'as-of'
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--as-of=name Dump system versioned tables as of the specified timestamp.
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Note that table structures are always dumped, irrespective of
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the date/time specified. Note that the timestamp is interpreted
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according to the --tz-utc setting (ref MDEV-26943 and --tz-utc).
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$ ./bin/mysqldump --help --verbose | grep -A5 -m1 'tz-utc'
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--tz-utc This option enables TIMESTAMP columns to be dumped and
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reloaded between servers in different time zones.
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mysqldump sets its connection time zone to UTC before
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commencing the dump, and adds SET TIME_ZONE=´+00:00´
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to the top of the dump file.
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Attachments
Issue Links
- is caused by
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MDEV-16355 Add option for mysqldump to read data as of specific timestamp from system-versioned tables
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- Closed
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- split from
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MDEV-26946 Various small mysqldump manual improvements for the --as-of and --tz-utc options
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- Open
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Activity
midenok sorry to say, but did you even read the bug report I wrote? A proposed text is/was already there, and is exactly one line longer than the current text.
Roel Maybe I read wrong this:
4. The mysqldump binary's help for -as-of should be changed in a similar matter as items 1 to 3 above.
So it requires to include this:
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1. It needs to be clarified that this option is only applicable to the data, not the table structure. The table structure is always dumped, irrespective of the date/time specified. @serg fyi, in case this is considered a bug.
CREATE TABLE t1 (a INT) WITH SYSTEM VERSIONING; |
INSERT t1 (a) VALUES (1),(2),(3); |
DELETE FROM t1 WHERE a=1; |
Followed by:
./bin/mysqldump -uroot -S./socket.sock --compact --as-of="1990-01-01 00:01" test t1
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Will dump the table structure but not the data.
2. In regards timestamps, the connection with -tz-utc / -skip-tz-utc would best be clarified to make it easier for users to understand why their timestamps are not working when dumping data. Perhaps something like:
Please note the interaction of this option with <a href="https://jira.mariadb.org/browse/MDEV-26943">--tz-utc</a>. |
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And where is the proposed text for the above? I see two p.4 though in your list so I referred to the first one.
Roel to avoid further misunderstanding please update this task description with exact instructions for this task only.
midenok Again, the proposed text for --tz-utc was already there and for --as-of I simply used the sentences which were also already there. I've added it into the description above for you.
midenok serg As mentioned in MDEV-26946, before documenting this, it needs to be validated that it is correct and expected behavior to dump table structures always. i.e. when a user dumps with an --as-of set to 1990 it will dump a table structure created in 2022, even if no data is included.
yes, as far as table structure is concerned — it's definitely correct and expected.
as far as --as-of help text is concerned — I agree that it could benefit from a second statement, like "Timestamp is interpreted according to the --tz-utc setting".
IMHO, the original proposed text above has two advantages not present in the proposed patch;
1) MDEV-26943 is a helpful reference
2) "This option enables TIMESTAMP columns to be dumped and reloaded between servers in different time zones." is (and was) helpful
There is also a typo: "versioned table" should read "versioned table(s)" as it can be more than one.
Roel We do not specify MDEV references in the UI, do we?
As for 2) this is obvious for SA having servers in different time zones. Like I said, --help is not man page.
--help is not the man page. --help briefly describes what each option does. Brevity is the main feature here: basically it lists what the options are available long and short for the user to interact. When the user wants details he reads the man page. That's the common UNIX practice!
If you think differently, please suggest the text for the p.4 and approve this ticket with serg.