opt: param indexScan columnHint/prefix scan

[wey-gu]

Introduction

For Cypher Param case, the index scan isn't optimal:

We could see there is no columnHint or prefix scan info for the indexScan, and it fully scans all data(rows: 51).

(root@nebula) [basketballplayer]> :param p0 => 'Tim Duncan';
(root@nebula) [basketballplayer]> profile MATCH (n: player) WHERE n.player.name == $p0 RETURN n;
+----------------------------------------------------+
| n                                                  |
+----------------------------------------------------+
| ("player100" :player{age: 42, name: "Tim Duncan"}) |
+----------------------------------------------------+
Got 1 rows (time spent 6760/13199 us)
...
-----+----------------+--------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------------------------
|  1 | IndexScan      | 2            | {                                                                                                                                                                     | outputVar: {                     |
|    |                |              | ver: 0, rows: 51, execTime: 0us, totalTime: 1683us                                                                                                                    |   "colNames": [                  |
|    |                |              | "storaged2":9779 exec/total: 437(us)/1359(us)                                                                                                                         |     "_vid"                       |
|    |                |              | "storaged1":9779 exec/total: 406(us)/1339(us)                                                                                                                         |   ],                             |
|    |                |              | "storaged0":9779 exec/total: 342(us)/1385(us)                                                                                                                         |   "type": "DATASET",             |
|    |                |              | storage_detail: {IndexLimitNode(limit=9223372036854775807):205(us),IndexProjectionNode(projectColumn=[_vid]):204(us),IndexVertexScanNode(IndexID=6, Path=()):197(us)} |   "name": "__IndexScan_1"        |
|    |                |              | }                                                                                                                                                                     | }                                |
|    |                |              |                                                                                                                                                                       | inputVar:                        |
|    |                |              |                                                                                                                                                                       | space: 1                         |
|    |                |              |                                                                                                                                                                       | dedup: false                     |
|    |                |              |                                                                                                                                                                       | limit: 9223372036854775807       |
|    |                |              |                                                                                                                                                                       | filter:                          |
|    |                |              |                                                                                                                                                                       | orderBy: []                      |
|    |                |              |                                                                                                                                                                       | schemaId: 2                      |
|    |                |              |                                                                                                                                                                       | isEdge: false                    |
|    |                |              |                                                                                                                                                                       | returnCols: [                    |
|    |                |              |                                                                                                                                                                       |   "_vid"                         |
|    |                |              |                                                                                                                                                                       | ]                                |
|    |                |              |                                                                                                                                                                       | indexCtx: [                      |
|    |                |              |                                                                                                                                                                       |   {                              |
|    |                |              |                                                                                                                                                                       |     "columnHints": [],           |
|    |                |              |                                                                                                                                                                       |     "filter": "",                |
|    |                |              |                                                                                                                                                                       |     "index_id": 6                |
|    |                |              |                                                                                                                                                                       |   }                              |
|    |                |              |                                                                                                                                                                       | ]                                |
-----+----------------+--------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------------------------
|  2 | Start          |              | ver: 0, rows: 0, execTime: 0us, totalTime: 27us                                                                                                                       | outputVar: {                     |
|    |                |              |                                                                                                                                                                       |   "colNames": [],                |
|    |                |              |                                                                                                                                                                       |   "type": "DATASET",             |
|    |                |              |                                                                                                                                                                       |   "name": "__Start_2"            |
|    |                |              |                                                                                                                                                                       | }                                |
-----+----------------+--------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------------------------

Contents

• ngbatis执行结果与nebula不一致 nebula-contrib/ngbatis#78

Related work

• Fix match index selection related to parameter in expression #4798