Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Align 2 prs from docs-cn (sql and planner) (#7005) #7013

Merged
merged 1 commit into from
Nov 25, 2021
Merged

Align 2 prs from docs-cn (sql and planner) (#7005) #7013

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
10 changes: 10 additions & 0 deletions optimizer-hints.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -186,6 +186,16 @@ The `AGG_TO_COP()` hint tells the optimizer to push down the aggregate operation
select /*+ AGG_TO_COP() */ sum(t1.a) from t t1;
```

### LIMIT_TO_COP()

The `LIMIT_TO_COP()` hint tells the optimizer to push down the `Limit` and `TopN` operators in the specified query block to the coprocessor. If the optimizer does not perform such an operation, it is recommended to use this hint. For example:

{{< copyable "sql" >}}

```sql
SELECT /*+ LIMIT_TO_COP() */ * FROM t WHERE a = 1 AND b > 10 ORDER BY c LIMIT 1;
```

### READ_FROM_STORAGE(TIFLASH[t1_name [, tl_name ...]], TIKV[t2_name [, tl_name ...]])

The `READ_FROM_STORAGE(TIFLASH[t1_name [, tl_name ...]], TIKV[t2_name [, tl_name ...]])` hint tells the optimizer to read specific table(s) from specific storage engine(s). Currently, this hint supports two storage engine parameters - `TIKV` and `TIFLASH`. If a table has an alias, use the alias as the parameter of `READ_FROM_STORAGE()`; if the table does not has an alias, use the table's original name as the parameter. For example:
Expand Down
2 changes: 0 additions & 2 deletions sql-statements/sql-statement-create-sequence.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -47,7 +47,6 @@ CREATE [TEMPORARY] SEQUENCE [IF NOT EXISTS] sequence_name
[ START [ WITH | = ] start ]
[ CACHE [=] cache | NOCACHE | NO CACHE]
[ CYCLE | NOCYCLE | NO CYCLE]
[ ORDER | NOORDER | NO ORDER]
[table_options]
```

Expand All @@ -62,7 +61,6 @@ CREATE [TEMPORARY] SEQUENCE [IF NOT EXISTS] sequence_name
| `START` | `MINVALUE` or `MAXVALUE`| Specifies the initial value of a sequence. When `INCREMENT` > `0`, the default value is `MINVALUE`. When `INCREMENT` < `0`, the default value is `MAXVALUE`. |
| `CACHE` | `1000` | Specifies the local cache size of a sequence in TiDB. |
| `CYCLE` | `NO CYCLE` | Specifies whether a sequence restarts from the minimum value (or maximum for the descending sequence). When `INCREMENT` > `0`, the default value is `MINVALUE`. When `INCREMENT` < `0`, the default value is `MAXVALUE`. |
| `ORDER` | `NO ORDER` | TiDB currently does not support the `ORDER` option and provides only syntax compatibility for it. |

## `SEQUENCE` function

Expand Down