makssent opened a new pull request, #40179:
URL: https://github.com/apache/shardingsphere/pull/40179
Changes proposed in this pull request:
- The Firebird grammar accepts an optional `NULLS FIRST` or `NULLS LAST`
after `ASC | DESC` in `orderByItem`; the new token `NULLS` is added to
`unreservedWord`, because Firebird does not reserve this word.
- `FirebirdStatementVisitor.visitOrderByItem` passes the `NullsOrderType`
of the item to the order by item segments, so the requested place of NULL
values is also kept when the proxy merges rows of several shards.
- The client receives the rows in the order of the server instead of
`isc_dsql_error` "You have an error in your SQL syntax".
Verification:
The same queries were executed directly against a real database and through
the proxy, and the results were compared.
* Server: Firebird 5.0
* Clients: Jaybird 5.0.13 and 6.0.6
`T_PLAIN (ID, NAME)` rows (2701, 'b'), (2702, NULL), (2703, 'a'), (2704,
NULL), (2705, 'c') are inserted and deleted with the same results directly and
through the proxy. Each query is `SELECT ID, NAME FROM T_PLAIN WHERE ID BETWEEN
2701 AND 2706 ORDER BY ...`; the table shows its `ORDER BY` items and the
returned rows.
Before the fix:
| Query | Proxy | Server | Match |
|---|---|---|---|
| `ORDER BY NAME NULLS FIRST, ID` | error 335544569 `isc_dsql_error`
"Dynamic SQL Error; You have an error in your SQL syntax: SELECT ..., null" |
2702 NULL, 2704 NULL, 2703 a, 2701 b, 2705 c | no |
| `ORDER BY NAME NULLS LAST, ID` | the same error | 2703 a, 2701 b, 2705
c, 2702 NULL, 2704 NULL | no |
| `ORDER BY NAME ASC NULLS LAST, ID` | the same error | 2703 a, 2701 b,
2705 c, 2702 NULL, 2704 NULL | no |
| `ORDER BY NAME DESC NULLS FIRST, ID` | the same error | 2702 NULL, 2704
NULL, 2705 c, 2701 b, 2703 a | no |
| `ORDER BY NAME DESC NULLS LAST, ID` | the same error | 2705 c, 2701 b,
2703 a, 2702 NULL, 2704 NULL | no |
| `ORDER BY 2 NULLS LAST, 1` | error 335544569 `isc_dsql_error` "Dynamic
SQL Error; You have an error in your SQL syntax: no viable alternative at input
'2NULLS'" | 2703 a, 2701 b, 2705 c, 2702 NULL, 2704 NULL | no |
| `ORDER BY UPPER(NAME) DESC NULLS FIRST, ID` | error 335544569
`isc_dsql_error` "Dynamic SQL Error; You have an error in your SQL syntax:
SELECT ..., null" | 2702 NULL, 2704 NULL, 2705 c, 2701 b, 2703 a | no |
After the fix:
| Query | Proxy | Server | Match |
|---|---|---|---|
| `ORDER BY NAME NULLS FIRST, ID` | 2702 NULL, 2704 NULL, 2703 a, 2701 b,
2705 c | 2702 NULL, 2704 NULL, 2703 a, 2701 b, 2705 c | yes |
| `ORDER BY NAME NULLS LAST, ID` | 2703 a, 2701 b, 2705 c, 2702 NULL, 2704
NULL | 2703 a, 2701 b, 2705 c, 2702 NULL, 2704 NULL | yes |
| `ORDER BY NAME ASC NULLS LAST, ID` | 2703 a, 2701 b, 2705 c, 2702 NULL,
2704 NULL | 2703 a, 2701 b, 2705 c, 2702 NULL, 2704 NULL | yes |
| `ORDER BY NAME DESC NULLS FIRST, ID` | 2702 NULL, 2704 NULL, 2705 c,
2701 b, 2703 a | 2702 NULL, 2704 NULL, 2705 c, 2701 b, 2703 a | yes |
| `ORDER BY NAME DESC NULLS LAST, ID` | 2705 c, 2701 b, 2703 a, 2702 NULL,
2704 NULL | 2705 c, 2701 b, 2703 a, 2702 NULL, 2704 NULL | yes |
| `ORDER BY 2 NULLS LAST, 1` | 2703 a, 2701 b, 2705 c, 2702 NULL, 2704
NULL | 2703 a, 2701 b, 2705 c, 2702 NULL, 2704 NULL | yes |
| `ORDER BY UPPER(NAME) DESC NULLS FIRST, ID` | 2702 NULL, 2704 NULL, 2705
c, 2701 b, 2703 a | 2702 NULL, 2704 NULL, 2705 c, 2701 b, 2703 a | yes |
---
Before committing this PR, I'm sure that I have checked the following
options:
- [x] My code follows the [code of
conduct](https://shardingsphere.apache.org/community/en/involved/conduct/code/)
of this project.
- [x] I have self-reviewed the commit code.
- [ ] I have (or in comment I request) added corresponding labels for the
pull request.
- [ ] I have passed maven check locally : `./mvnw clean install -B -T1C
-Dmaven.javadoc.skip -Dmaven.jacoco.skip -e`.
- [ ] I have made corresponding changes to the documentation.
- [x] I have added corresponding unit tests for my changes.
- [ ] I have updated the Release Notes of the current development version.
For more details, see [Update Release
Note](https://shardingsphere.apache.org/community/en/involved/contribute/contributor/)
- [ ] I have specified the tool and the affected files or area for
substantial AI assistance, as required by the [AI-assisted contribution policy].
[AI-assisted contribution policy]:
https://github.com/apache/shardingsphere/blob/master/AI_POLICY.md
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