From 35aed7653955340e9457b47e09e60753a944d5dd Mon Sep 17 00:00:00 2001 From: slzhou Date: Wed, 21 Feb 2024 13:39:15 +0800 Subject: [PATCH] docs: add para_tables_sort() hint --- docs/en/12-taos-sql/06-select.md | 6 ++++-- docs/zh/12-taos-sql/06-select.md | 5 +++-- 2 files changed, 7 insertions(+), 4 deletions(-) diff --git a/docs/en/12-taos-sql/06-select.md b/docs/en/12-taos-sql/06-select.md index 1fc6fb7e67..0cd2d06989 100755 --- a/docs/en/12-taos-sql/06-select.md +++ b/docs/en/12-taos-sql/06-select.md @@ -24,7 +24,7 @@ SELECT [hints] [DISTINCT] [TAGS] select_list hints: /*+ [hint([hint_param_list])] [hint([hint_param_list])] */ hint: - BATCH_SCAN | NO_BATCH_SCAN | SORT_FOR_GROUP + BATCH_SCAN | NO_BATCH_SCAN | SORT_FOR_GROUP | PARA_TABLES_SORT select_list: select_expr [, select_expr] ... @@ -87,12 +87,13 @@ Hints are a means of user control over query optimization for individual stateme The list of currently supported Hints is as follows: -| **Hint** | **Params** | **Comment** | **Scopt** | +| **Hint** | **Params** | **Comment** | **Scope** | | :-----------: | -------------- | -------------------------- | -----------------------------------| | BATCH_SCAN | None | Batch table scan | JOIN statment for stable | | NO_BATCH_SCAN | None | Sequential table scan | JOIN statment for stable | | SORT_FOR_GROUP| None | Use sort for partition, conflict with PARTITION_FIRST | With normal column in partition by list | | PARTITION_FIRST| None | Use Partition before aggregate, conflict with SORT_FOR_GROUP | With normal column in partition by list | +| PARA_TABLES_SORT| None | When sorting the supertable rows by timestamp, No temporary disk space is used | Sorting the supertable rows by timestamp | For example: @@ -100,6 +101,7 @@ For example: SELECT /*+ BATCH_SCAN() */ a.ts FROM stable1 a, stable2 b where a.tag0 = b.tag0 and a.ts = b.ts; SELECT /*+ SORT_FOR_GROUP() */ count(*), c1 FROM stable1 PARTITION BY c1; SELECT /*+ PARTITION_FIRST() */ count(*), c1 FROM stable1 PARTITION BY c1; +SELECT /*+ PARA_TABLES_SORT() */ * from stable1 order by ts; ``` ## Lists diff --git a/docs/zh/12-taos-sql/06-select.md b/docs/zh/12-taos-sql/06-select.md index 2a7dff6f7d..43b32efe32 100755 --- a/docs/zh/12-taos-sql/06-select.md +++ b/docs/zh/12-taos-sql/06-select.md @@ -24,7 +24,7 @@ SELECT [hints] [DISTINCT] [TAGS] select_list hints: /*+ [hint([hint_param_list])] [hint([hint_param_list])] */ hint: - BATCH_SCAN | NO_BATCH_SCAN | SORT_FOR_GROUP + BATCH_SCAN | NO_BATCH_SCAN | SORT_FOR_GROUP | PARA_TABLES_SORT select_list: select_expr [, select_expr] ... @@ -93,13 +93,14 @@ Hints 是用户控制单个语句查询优化的一种手段，当 Hint 不适 | NO_BATCH_SCAN | 无 | 采用顺序读表的方式 | 超级表 JOIN 语句 | | SORT_FOR_GROUP| 无 | 采用sort方式进行分组, 与PARTITION_FIRST冲突 | partition by 列表有普通列时 | | PARTITION_FIRST| 无 | 在聚合之前使用PARTITION计算分组, 与SORT_FOR_GROUP冲突 | partition by 列表有普通列时 | - +| PARA_TABLES_SORT| 无 | 超级表的数据按时间戳排序时, 不使用临时磁盘空间, 只使用内存 | 超级表的数据按时间戳排序时 | 举例： ```sql SELECT /*+ BATCH_SCAN() */ a.ts FROM stable1 a, stable2 b where a.tag0 = b.tag0 and a.ts = b.ts; SELECT /*+ SORT_FOR_GROUP() */ count(*), c1 FROM stable1 PARTITION BY c1; SELECT /*+ PARTITION_FIRST() */ count(*), c1 FROM stable1 PARTITION BY c1; +SELECT /*+ PARA_TABLES_SORT() */ * from stable1 order by ts; ``` ## 列表