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debug: add capability to "force" a load-based split #55116

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tbg opened this issue Oct 1, 2020 · 3 comments
Closed

debug: add capability to "force" a load-based split #55116

tbg opened this issue Oct 1, 2020 · 3 comments
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A-kv Anything in KV that doesn't belong in a more specific category. C-enhancement Solution expected to add code/behavior + preserve backward-compat (pg compat issues are exception) good first issue no-issue-activity T-kv KV Team X-stale

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@tbg
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tbg commented Oct 1, 2020 •
edited by cockroach-jira-scripts
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Is your feature request related to a problem? Please describe.
When a user has a range that they wish to split to better distribute load (for example during a crisis situation), but load-based splitting does not do the job, the user has to manually construct a split key for use with ALTER TABLE ... SPLIT.

Describe the solution you'd like
Either via the UI or SQL, "force" a load-based split, meaning that the range will split based on the leader's best guess.

Describe alternatives you've considered
An alternative is to set the cluster setting that controls load-based split aggressiveness. However, this is a highly non-local solution that may cause many unrelated and possibly detrimental splits.

Jira issue: CRDB-3693
@tbg tbg added A-kv Anything in KV that doesn't belong in a more specific category. C-enhancement Solution expected to add code/behavior + preserve backward-compat (pg compat issues are exception) labels Oct 1, 2020
@jlinder jlinder added the T-kv KV Team label Jun 16, 2021
@lunevalex
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@tbg I was thinking about the proposal and based on my observations from #72305 I think the best option would be to extend the ALTER RANGE syntax to support this, I think we can offer the following syntax to meet the proposed use cases ALTER RANGE 10 SPLIT and ALTER RANGE SPLIT FOR (SELECT range_id from crdb_internal_ranges where table_name = 'foo'

@ajwerner
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A different approach to this problem is to move the thresholds for load-based splitting into zone/span configs. That's not to take anything away from the more precise statements @lunevalex is proposing. Both seem valuable. Increasingly, I think more and more KV allocator decisions should be configured on a per-span basis.

lunevalex added a commit to lunevalex/cockroach that referenced this issue Mar 16, 2022
@lunevalex
sql: add ALTER RANGE x SPLIT syntax
002d094 
Fixes cockroachdb#55116

Extend the ALTER RANGE syntax to support splitting a range.
ALTER RANGE x SPLIT will split a range at the best available
load based key. The new command will not perform a split directly
but rather advise the load based split decider to ignore the QPS
threshold and perform a load based split based on the lastest
available information. The decider has a 10s timeout built in between
deciding to split and determing the split key, so the actual split will
occur approximately 10s after the commnad is run.

To support all of this we changed AdminSplitRequest and added a new parameter
LoadBased. When set this will trigger a load based split on the range
through the split_queue.

Release note(sql change): Enhance the ALTER RANGE syntax to
allow an operator to manually perform a load based split of
a range.
@lunevalex lunevalex mentioned this issue Mar 16, 2022
Closed
lunevalex added a commit to lunevalex/cockroach that referenced this issue Jun 13, 2022
@lunevalex
sql: add ALTER RANGE x SPLIT syntax
bd52013 
Fixes cockroachdb#55116

Extend the ALTER RANGE syntax to support splitting a range.
ALTER RANGE x SPLIT will split a range at the best available
load based key. The new command will not perform a split directly
but rather advise the load based split decider to ignore the QPS
threshold and perform a load based split based on the lastest
available information. The decider has a 10s timeout built in between
deciding to split and determing the split key, so the actual split will
occur approximately 10s after the commnad is run.

To support all of this we changed AdminSplitRequest and added a new parameter
LoadBased. When set this will trigger a load based split on the range
through the split_queue.

Release note(sql change): Enhance the ALTER RANGE syntax to
allow an operator to manually perform a load based split of
a range.
lunevalex added a commit to lunevalex/cockroach that referenced this issue Jun 14, 2022
@lunevalex
sql: add ALTER RANGE x SPLIT syntax
91930ed 
Fixes cockroachdb#55116

Extend the ALTER RANGE syntax to support splitting a range.
ALTER RANGE x SPLIT will split a range at the best available
load based key. The new command will not perform a split directly
but rather advise the load based split decider to ignore the QPS
threshold and perform a load based split based on the lastest
available information. The decider has a 10s timeout built in between
deciding to split and determing the split key, so the actual split will
occur approximately 10s after the commnad is run.

To support all of this we changed AdminSplitRequest and added a new parameter
LoadBased. When set this will trigger a load based split on the range
through the split_queue.

Release note(sql change): Enhance the ALTER RANGE syntax to
allow an operator to manually perform a load based split of
a range.
@tbg tbg mentioned this issue Jun 28, 2022
Closed
lunevalex added a commit to lunevalex/cockroach that referenced this issue Sep 27, 2022
@lunevalex
sql: add ALTER RANGE x SPLIT syntax
dd79071 
Fixes cockroachdb#55116

Extend the ALTER RANGE syntax to support splitting a range.
ALTER RANGE x SPLIT will split a range at the best available
load based key. The new command will not perform a split directly
but rather advise the load based split decider to ignore the QPS
threshold and perform a load based split based on the lastest
available information. The decider has a 10s timeout built in between
deciding to split and determing the split key, so the actual split will
occur approximately 10s after the commnad is run.

To support all of this we changed AdminSplitRequest and added a new parameter
LoadBased. When set this will trigger a load based split on the range
through the split_queue.

Release note(sql change): Enhance the ALTER RANGE syntax to
allow an operator to manually perform a load based split of
a range.
lunevalex added a commit to lunevalex/cockroach that referenced this issue Oct 3, 2022
@lunevalex
sql: add ALTER RANGE x SPLIT syntax
2db4d4b 
Fixes cockroachdb#55116

Extend the ALTER RANGE syntax to support splitting a range.
ALTER RANGE x SPLIT will split a range at the best available
load based key. The new command will not perform a split directly
but rather advise the load based split decider to ignore the QPS
threshold and perform a load based split based on the lastest
available information. The decider has a 10s timeout built in between
deciding to split and determing the split key, so the actual split will
occur approximately 10s after the commnad is run.

To support all of this we changed AdminSplitRequest and added a new parameter
LoadBased. When set this will trigger a load based split on the range
through the split_queue.

Release note(sql change): Enhance the ALTER RANGE syntax to
allow an operator to manually perform a load based split of
a range.
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github-actions bot commented Sep 6, 2023

We have marked this issue as stale because it has been inactive for
18 months. If this issue is still relevant, removing the stale label
or adding a comment will keep it active. Otherwise, we'll close it in
10 days to keep the issue queue tidy. Thank you for your contribution
to CockroachDB!

@github-actions github-actions bot closed this as not planned Won't fix, can't repro, duplicate, stale Sep 18, 2023
@github-project-automation github-project-automation bot moved this to Closed in KV Aug 28, 2024
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sql: add ALTER RANGE x SPLIT syntax lunevalex/cockroach
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@jlinder @ajwerner @tbg @lunevalex