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73 lines
4.1 KiB
Markdown
73 lines
4.1 KiB
Markdown
---
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slug: /en/operations/system-tables/scheduler
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---
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# scheduler
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Contains information and status for [scheduling nodes](/docs/en/operations/workload-scheduling.md/#hierarchy) residing on the local server.
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This table can be used for monitoring. The table contains a row for every scheduling node.
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Example:
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``` sql
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SELECT *
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FROM system.scheduler
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WHERE resource = 'network_read' AND path = '/prio/fair/prod'
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FORMAT Vertical
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```
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``` text
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Row 1:
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──────
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resource: network_read
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path: /prio/fair/prod
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type: fifo
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weight: 5
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priority: 0
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is_active: 0
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active_children: 0
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dequeued_requests: 67
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dequeued_cost: 4692272
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busy_periods: 63
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vruntime: 938454.1999999989
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system_vruntime: ᴺᵁᴸᴸ
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queue_length: 0
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queue_cost: 0
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budget: -60524
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is_satisfied: ᴺᵁᴸᴸ
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inflight_requests: ᴺᵁᴸᴸ
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inflight_cost: ᴺᵁᴸᴸ
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max_requests: ᴺᵁᴸᴸ
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max_cost: ᴺᵁᴸᴸ
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max_speed: ᴺᵁᴸᴸ
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max_burst: ᴺᵁᴸᴸ
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throttling_us: ᴺᵁᴸᴸ
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tokens: ᴺᵁᴸᴸ
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```
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Columns:
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- `resource` (`String`) - Resource name
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- `path` (`String`) - Path to a scheduling node within this resource scheduling hierarchy
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- `type` (`String`) - Type of a scheduling node.
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- `weight` (`Float64`) - Weight of a node, used by a parent node of `fair`` type.
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- `priority` (`Int64`) - Priority of a node, used by a parent node of 'priority' type (Lower value means higher priority).
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- `is_active` (`UInt8`) - Whether this node is currently active - has resource requests to be dequeued and constraints satisfied.
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- `active_children` (`UInt64`) - The number of children in active state.
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- `dequeued_requests` (`UInt64`) - The total number of resource requests dequeued from this node.
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- `dequeued_cost` (`UInt64`) - The sum of costs (e.g. size in bytes) of all requests dequeued from this node.
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- `busy_periods` (`UInt64`) - The total number of deactivations of this node.
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- `vruntime` (`Nullable(Float64)`) - For children of `fair` nodes only. Virtual runtime of a node used by SFQ algorithm to select the next child to process in a max-min fair manner.
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- `system_vruntime` (`Nullable(Float64)`) - For `fair` nodes only. Virtual runtime showing `vruntime` of the last processed resource request. Used during child activation as the new value of `vruntime`.
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- `queue_length` (`Nullable(UInt64)`) - For `fifo` nodes only. Current number of resource requests residing in the queue.
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- `queue_cost` (`Nullable(UInt64)`) - For `fifo` nodes only. Sum of costs (e.g. size in bytes) of all requests residing in the queue.
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- `budget` (`Nullable(Int64)`) - For `fifo` nodes only. The number of available "cost units" for new resource requests. Can appear in case of discrepancy of estimated and real costs of resource requests (e.g. after read/write failure)
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- `is_satisfied` (`Nullable(UInt8)`) - For constraint nodes only (e.g. `inflight_limit`). Equals `1` if all the constraint of this node are satisfied.
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- `inflight_requests` (`Nullable(Int64)`) - For `inflight_limit` nodes only. The number of resource requests dequeued from this node, that are currently in consumption state.
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- `inflight_cost` (`Nullable(Int64)`) - For `inflight_limit` nodes only. The sum of costs (e.g. bytes) of all resource requests dequeued from this node, that are currently in consumption state.
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- `max_requests` (`Nullable(Int64)`) - For `inflight_limit` nodes only. Upper limit for `inflight_requests` leading to constraint violation.
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- `max_cost` (`Nullable(Int64)`) - For `inflight_limit` nodes only. Upper limit for `inflight_cost` leading to constraint violation.
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- `max_speed` (`Nullable(Float64)`) - For `bandwidth_limit` nodes only. Upper limit for bandwidth in tokens per second.
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- `max_burst` (`Nullable(Float64)`) - For `bandwidth_limit` nodes only. Upper limit for `tokens` available in token-bucket throttler.
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- `throttling_us` (`Nullable(Int64)`) - For `bandwidth_limit` nodes only. Total number of microseconds this node was in throttling state.
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- `tokens` (`Nullable(Float64)`) - For `bandwidth_limit` nodes only. Number of tokens currently available in token-bucket throttler.
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