Updated the Schema Cache limitations #19374
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Co-authored-by: Lilian Lee <[email protected]>
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[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: hfxsd The full list of commands accepted by this bot can be found here. The pull request process is described here
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| @@ -36,3 +36,8 @@ In scenarios with a large number of databases and tables, the following known is | |||
| - `SHOW FULL TABLES` | |||
| - `FLASHBACK` | |||
| - `ALTER TABLE ... SET TIFLASH MODE ...` | |||
| - When you use tables with the [`AUTO_INCREMENT`](/auto-increment.md) or [`AUTO_RANDOM`](/auto-random.md) attribute, a small schema cache size might cause these tables to frequently enter and leave the cache. You can monitor it through the schema cache hit rate and size on the monitoring panel. This can result in the allocated ID range becoming invalid before being fully used, leading to ID jumps. In write-intensive scenarios, this might even exhaust the ID range. To minimize abnormal ID allocation behavior and improve system stability, it is recommended to take the following measures: | |||
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| - Increase the schema cache size to reduce frequent evictions. | |||
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Suggested change
| - Increase the schema cache size to reduce frequent evictions. | |
| - View the hit rate and size of the schema cache on the monitoring panel to assess whether the cache settings are reasonable. Increase the schema cache size properly to reduce frequent evictions. |
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| @@ -36,3 +36,8 @@ In scenarios with a large number of databases and tables, the following known is | |||
| - `SHOW FULL TABLES` | |||
| - `FLASHBACK` | |||
| - `ALTER TABLE ... SET TIFLASH MODE ...` | |||
| - When you use tables with the [`AUTO_INCREMENT`](/auto-increment.md) or [`AUTO_RANDOM`](/auto-random.md) attribute, a small schema cache size might cause these tables to frequently enter and leave the cache. You can monitor it through the schema cache hit rate and size on the monitoring panel. This can result in the allocated ID range becoming invalid before being fully used, leading to ID jumps. In write-intensive scenarios, this might even exhaust the ID range. To minimize abnormal ID allocation behavior and improve system stability, it is recommended to take the following measures: | |||
There was a problem hiding this comment.
Suggested change
| - When you use tables with the [`AUTO_INCREMENT`](/auto-increment.md) or [`AUTO_RANDOM`](/auto-random.md) attribute, a small schema cache size might cause these tables to frequently enter and leave the cache. You can monitor it through the schema cache hit rate and size on the monitoring panel. This can result in the allocated ID range becoming invalid before being fully used, leading to ID jumps. In write-intensive scenarios, this might even exhaust the ID range. To minimize abnormal ID allocation behavior and improve system stability, it is recommended to take the following measures: | |
| - When you use tables with the [`AUTO_INCREMENT`](/auto-increment.md) or [`AUTO_RANDOM`](/auto-random.md) attribute, a small schema cache size might cause the meta data of these tables to frequently enter and leave the cache. This can result in the allocated ID range becoming invalid before being fully used, leading to ID jumps. In write-intensive scenarios, this might even exhaust the ID range. To minimize abnormal ID allocation behavior and improve system stability, it is recommended to take the following measures: |
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a small schema cache size might cause the metadata of these tables to be frequently cached and evicted in memory.
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In response to a cherrypick label: new pull request created to branch |
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Updated the Schema Cache limitations
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