add docs for TiFlash MinTso scheduler #19222
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Signed-off-by: xufei <[email protected]>
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Signed-off-by: xufei <[email protected]>
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tiflash/tiflash-mintso-scheduler.md
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| By introducing soft limit and hard limit, the MinTSO scheduler effectively avoids system deadlock while controlling the number of system threads. However, in high concurrency scenarios, it is possible that most queries will have only part of their MPP tasks scheduled. Queries with only part MPP tasks scheduled cannot execute normally, leading to low system execution efficiency. To avoid this situation, TiFlash introduces a limit at the query level for the MinTSO scheduler, called active_set_soft_limit. This limit requires that only up to active_set_soft_limit queries' MPP tasks can participate in scheduling; other queries' MPP Tasks do not participate in scheduling, and only after the current queries finish can new queries participate in scheduling. This limit is only a soft limit because for the MinTSO query, all its MPP tasks can be scheduled directly as long as the number of system threads does not exceed the hard limit. |
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| By introducing soft limit and hard limit, the MinTSO scheduler effectively avoids system deadlock while controlling the number of system threads. However, in high concurrency scenarios, it is possible that most queries will have only part of their MPP tasks scheduled. Queries with only part MPP tasks scheduled cannot execute normally, leading to low system execution efficiency. To avoid this situation, TiFlash introduces a limit at the query level for the MinTSO scheduler, called active_set_soft_limit. This limit requires that only up to active_set_soft_limit queries' MPP tasks can participate in scheduling; other queries' MPP Tasks do not participate in scheduling, and only after the current queries finish can new queries participate in scheduling. This limit is only a soft limit because for the MinTSO query, all its MPP tasks can be scheduled directly as long as the number of system threads does not exceed the hard limit. | |
| By introducing soft limit and hard limit, the MinTSO scheduler effectively avoids system deadlock while controlling the number of system threads. In high concurrency scenarios, however, most queries might only have part of their MPP tasks scheduled. Queries with only part of MPP tasks scheduled cannot execute normally, leading to low system execution efficiency. To avoid this situation, TiFlash introduces a query-level limit for the MinTSO scheduler, called active_set_soft_limit. This limit allows only MPP tasks of up to active_set_soft_limit queries to participate in scheduling; MPP tasks of other queries do not participate in scheduling, and only after the current queries finish can new queries participate in scheduling. This limit is only a soft limit because for the MinTSO query, all its MPP tasks can be scheduled directly as long as the number of system threads does not exceed the hard limit. |
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[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: lilin90 The full list of commands accepted by this bot can be found here. The pull request process is described here
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windtalker
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Nov 4, 2024
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In response to a cherrypick label: new pull request created to branch |
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In response to a cherrypick label: new pull request created to branch |
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In response to a cherrypick label: new pull request created to branch |
16 tasks
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In response to a cherrypick label: new pull request created to branch |
16 tasks
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In response to a cherrypick label: new pull request created to branch |
16 tasks
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In response to a cherrypick label: new pull request created to branch |
16 tasks
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In response to a cherrypick label: new pull request created to branch |
16 tasks
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In response to a cherrypick label: new pull request created to branch |
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