Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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10.3(EOL), 10.4(EOL), 10.5, 10.6, 10.7(EOL), 10.8(EOL)
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None
Description
When we need to add/remove or change LIMIT, INTERVAL, AUTO we have to recreate partitioning from scratch. Such operations should be done fast. To remove options like LIMIT or INTERVAL one should write:
alter table t1 partition by system_time; |
The command checks whether it is new or existing SYSTEM_TIME partitioning. And in the case of new it behaves as CREATE would do: adds default number of partitions (2). If SYSTEM_TIME partitioning already existed it just changes its options: removes unspecified ones and adds/changes those specified explicitly. In case when partitions list was supplied it behaves as usual: does full repartitioning.
Examples:
create or replace table t1 (x int) with system versioning |
partition by system_time limit 100 partitions 4; |
# Change LIMIT
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alter table t1 partition by system_time limit 33; |
# Remove LIMIT
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alter table t1 partition by system_time; |
# This does full repartitioning |
alter table t1 partition by system_time limit 33 partitions 4; |
# This does data copy as pruning will require records in correct partitions |
alter table t1 partition by system_time interval 1 hour |
starts '2000-01-01 00:00:00'; |
# But this works fast, LIMIT will apply to DML commands |
alter table t1 partition by system_time limit 33; |
Attachments
Issue Links
- is blocked by
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MDEV-19903 Setup default partitions for system versioning
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- Closed
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- is duplicated by
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- Closed
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Activity
We agreed that server behaviour better to change in the new versions. Also it should be documentated.
Please update documenation for SYSTEM_TIME partitioning in 10.8 according to this task.
LIMIT and INTERVAL can be seen, at least by users, as attributes of both partitioning (the process) and individual partitions. Some users can reasonably expect that the change will affect existing partitions and distribution of existing data, especially since that's how it already works.
This keyword should apply to partitioning only. Individual attributes apply in partitions list.
julien.fritsch Why you did not automate that on closing the issue?
I don't think
MDEV-25540is a suitable justification for this.AUTO attribute in
MDEV-25540only affects the process of partitioning – that is, defines how new partitions are created or not created. For already existing ones, it has no meaning and thus its change doesn't anyhow affect them.LIMIT and INTERVAL can be seen, at least by users, as attributes of both partitioning (the process) and individual partitions. Some users can reasonably expect that the change will affect existing partitions and distribution of existing data, especially since that's how it already works.