doc: complementary to desc of in-mem-slow-query-topn-num and and in-mem-slow-query-recent-num.
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Signed-off-by: AilinKid <[email protected]>
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AilinKid
changed the title
in-mem-slow-query-topn-num and and in-mem-slow-query-recent-num`.in-mem-slow-query-topn-num and and in-mem-slow-query-recent-num.
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@AilinKid Could you please invite a tech reviewer? Thanks! |
hawkingrei
approved these changes
Jun 17, 2025
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@hawkingrei: adding LGTM is restricted to approvers and reviewers in OWNERS files. In response to this: Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository. |
Oreoxmt
reviewed
Jun 18, 2025
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| > **内存查询优先**: 当查询 `INFORMATION_SCHEMA.SLOW_QUERY` 表时候，TiDB 首先检查内存堆上缓存的慢查询，不行然后再去解析节点上的慢查询日志文件，`in-mem-slow-query-topn-num` 提供了指向内存堆中最慢的 N 个慢查询的堆内存缓存数量，该内存堆可以用来提供最慢慢查询的快速内存访问，从而避免解析日志文件。 | ||
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| > **内存消耗**: 该参数用于在快速检索最慢 N 个特征性慢查询的能力与慢查询堆内存占用控制之间实现平衡。设置的太高会导致内存堆在收集慢查询上消耗过多内存，设置太小可能会导致无法提供足够有效的最慢历史慢查询上下文，从而导致需要解析全量的日志文件来获取完整的慢查询信息。 | ||
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| + 每个 tidb 实例缓存在内存堆中的最慢的 slow query 个数。 |
There was a problem hiding this comment.
Suggested change
| > **内存查询优先**: 当查询 `INFORMATION_SCHEMA.SLOW_QUERY` 表时候，TiDB 首先检查内存堆上缓存的慢查询，不行然后再去解析节点上的慢查询日志文件，`in-mem-slow-query-topn-num` 提供了指向内存堆中最慢的 N 个慢查询的堆内存缓存数量，该内存堆可以用来提供最慢慢查询的快速内存访问，从而避免解析日志文件。 | |
| > **内存消耗**: 该参数用于在快速检索最慢 N 个特征性慢查询的能力与慢查询堆内存占用控制之间实现平衡。设置的太高会导致内存堆在收集慢查询上消耗过多内存，设置太小可能会导致无法提供足够有效的最慢历史慢查询上下文，从而导致需要解析全量的日志文件来获取完整的慢查询信息。 | |
| + 每个 tidb 实例缓存在内存堆中的最慢的 slow query 个数。 | |
| + 用于设置每个 TiDB 实例在内存中缓存的最慢的慢查询数量，以提升访问慢查询时的查询性能。具体功能如下： | |
| + **优化查询流程**：查询 `INFORMATION_SCHEMA.SLOW_QUERY` 表时，TiDB 会优先从内存中读取缓存的慢查询记录。只有在缓存未命中时，TiDB 才会解析本地慢查询日志文件。通过设置 `in-mem-slow-query-topn-num`，你可以指定最多在内存中缓存多少条最慢的慢查询，从而加快访问最慢慢查询的速度并减少日志文件解析的开销。 | |
| + **平衡内存使用**：该配置项有助于在提升最慢 N 个慢查询检索效率与控制内存占用之间实现平衡。值设置过高可能导致慢查询缓存占用过多内存，值设置过低则可能因缓存不足而频繁解析日志文件，从而需要解析全量的日志文件以获取完整的慢查询记录。 | |
Oreoxmt
reviewed
Jun 18, 2025
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| > **内存查询优先**: 当查询 `INFORMATION_SCHEMA.SLOW_QUERY` 表时候，TiDB 首先检查内存堆上缓存的慢查询，不行然后再去解析节点上的慢查询日志文件，`in-mem-slow-query-recent-num` 提供了指向内存堆中最近的 N 个慢查询的堆内存缓存数量，该内存堆可以用来提供最近慢查询的快速内存访问，从而避免解析日志文件。 | ||
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| > **内存消耗**: 该参数用于在快速检索最近 N 个特征性慢查询的能力与慢查询堆内存占用控制之间实现平衡。设置的太高会导致内存堆在收集慢查询上消耗过多内存，设置太小可能会导致无法提供足够有效的最近历史慢查询上下文，从而导致需要解析全量的日志文件来获取完整的慢查询信息。 | ||
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| + 每个 tidb 实例缓存在内存堆中的最近使用的 slow query 个数。 |
There was a problem hiding this comment.
Suggested change
| > **内存查询优先**: 当查询 `INFORMATION_SCHEMA.SLOW_QUERY` 表时候，TiDB 首先检查内存堆上缓存的慢查询，不行然后再去解析节点上的慢查询日志文件，`in-mem-slow-query-recent-num` 提供了指向内存堆中最近的 N 个慢查询的堆内存缓存数量，该内存堆可以用来提供最近慢查询的快速内存访问，从而避免解析日志文件。 | |
| > **内存消耗**: 该参数用于在快速检索最近 N 个特征性慢查询的能力与慢查询堆内存占用控制之间实现平衡。设置的太高会导致内存堆在收集慢查询上消耗过多内存，设置太小可能会导致无法提供足够有效的最近历史慢查询上下文，从而导致需要解析全量的日志文件来获取完整的慢查询信息。 | |
| + 每个 tidb 实例缓存在内存堆中的最近使用的 slow query 个数。 | |
| + 用于设置每个 TiDB 实例在内存中缓存的最近使用的慢查询数量，以支持快速访问最近发生的慢查询记录。具体功能如下： | |
| + **优化查询流程**：查询 `INFORMATION_SCHEMA.SLOW_QUERY` 表时，TiDB 会优先从内存中读取缓存的慢查询记录。如果缓存中没有匹配项，TiDB 会解析本地慢查询日志文件。通过设置 `in-mem-slow-query-recent-num`，你可以指定最多在内存中保留多少条最近的慢查询，以提升查询响应速度。 | |
| + **平衡内存使用**：该配置项有助于在提升最近 N 个慢查询检索效率与控制内存占用之间实现平衡。值设置过高可能导致内存占用过多，从而影响系统整体性能。值设置过低则可能导致上下文信息不足，从而需要解析全量的日志文件以获取完整的慢查询记录。 | |
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