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Announce GA of memory control on stats cache #19226

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Dec 9, 2024
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Announce GA of memory control on stats cache #19226

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effa7f1
include announcement to make stats cache GA
songrijie Dec 7, 2024
a1afc15
Update release-7.4.0.md
songrijie Dec 7, 2024
eb9b19a
Update release-7.4.0.md
songrijie Dec 7, 2024
8b3a8a7
include issue#
songrijie Dec 8, 2024
5d3677f
Update releases/release-7.4.0.md
hfxsd Dec 8, 2024
9964d32
Update releases/release-7.4.0.md
hfxsd Dec 9, 2024
520beaf
Update releases/release-7.4.0.md
hfxsd Dec 9, 2024
7915edf
Update releases/release-7.4.0.md
hfxsd Dec 9, 2024
e8cce4d
Update wording
lilin90 Dec 9, 2024
a1450f7
Add the value range for the system variable
lilin90 Dec 9, 2024
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8 changes: 8 additions & 0 deletions releases/release-7.4.0.md
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Expand Up @@ -199,6 +199,14 @@ TiDB 版本：7.4.0

更多信息，请参考[用户文档](/system-variables.md#tidb_opt_enable_hash_join-从-v656v712-和-v740-版本开始引入)。

* 控制统计信息缓存成为正式功能 (GA) [#45367](https://github.com/pingcap/tidb/issues/45367) @[hawkingrei](https://github.com/hawkingrei)

TiDB 实例可以缓存表的统计信息，以加速执行计划的生成，提升 SQL 执行性能。从 v6.1.0 开始，引入了系统变量 [`tidb_stats_cache_mem_quota`](/system-variables.md#tidb_stats_cache_mem_quota-从-v610-版本开始引入)，你可以通过设置该变量，控制统计信息缓存占用的内存上限。当统计信息缓存达到限额时，TiDB 会自动驱逐不活跃的缓存，从而控制实例的内存使用，提升稳定性。

从 v7.4.0 开始，该功能成为正式功能 (GA)。

更多信息，请参考[用户文档](/system-variables.md#tidb_stats_cache_mem_quota-从-v610-版本开始引入)。

### SQL 功能

* TiDB 支持完整的分区类型管理功能 [#42728](https://github.com/pingcap/tidb/issues/42728) @[mjonss](https://github.com/mjonss)
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5 changes: 3 additions & 2 deletions system-variables.md
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Expand Up @@ -4803,8 +4803,9 @@ Query OK, 0 rows affected, 1 warning (0.00 sec)
- 是否受 Hint [SET_VAR](/optimizer-hints.md#set_varvar_namevar_value) 控制：否
- 类型：整数型
- 单位：字节
- 默认值：`0`，自动设置内部统计信息缓存使用内存的上限为总内存的一半。
- 这个变量用于控制 TiDB 内部统计信息缓存使用内存的上限。
- 默认值：`0`，表示自动设置统计信息缓存的内存使用上限为总内存的一半。
- 范围：`[0, 1099511627776]`
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@lilin90 lilin90 Dec 9, 2024 •
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FYI. I added the value range via a1450f7 to align the description with that in English: https://docs.pingcap.com/tidb/v7.5/system-variables#tidb_stats_cache_mem_quota-new-in-v610
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Yes

- 这个变量用于控制 TiDB 统计信息缓存的内存使用上限。

### `tidb_stats_load_sync_wait` <span class="version-mark">从 v5.4.0 版本开始引入</span>

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