离线导入3亿带索引关系边报bad_alloc

[yzjzgr]

Environment:

OS: [centos 7]
CPU: [Intel(R) Xeon(R) Platinum 8269CY CPU @ 2.50GHz 8 cores]
MEM: 32G
TuGraph-DB Version [e.g. 4.1.0]
standalone

Describe the bug
图schema:
{
"schema": [
{
"label": "entity",
"type": "VERTEX",
"properties": [
{ "name": "primary_key", "type": "STRING" },
{ "name": "entity_type", "type": "STRING" },
{ "name": "entity_properties", "type": "STRING","optional": true }
],
"primary": "primary_key"
},
{
"label": "relation",
"type": "EDGE",
"properties": [
{ "name": "relation_type", "type": "STRING", "optional": false },
{ "name": "relation_unique_id", "type": "STRING", "optional": false, "index":true, "unique":false },
{ "name": "relation_properties", "type": "STRING", "optional": true }
],
"constraints": [["entity", "entity"]]
}
]
}

复现步骤：

1. 向以上schema图离线写入1.5亿顶点3亿关系边
   离线导入过程报bad_alloc。
   另外将边属性relation_unique_id改为无索引，数据可以被正常导入。
   也希望关系边属性有唯一索引的场景下，支持离线导入

[ljcui]

可以测试下在边的json schema里面加上 "detach_property": true 配置项，这个会优化加索引的速度和内存消耗，类似下面

{
	"label": "relation",
	"type": "EDGE",
	"detach_property": true,
	"properties": [{
			"name": "relation_type",
			"type": "STRING",
			"optional": false
		},
		{
			"name": "relation_unique_id",
			"type": "STRING",
			"optional": false,
			"index": true,
			"unique": false
		},
		{
			"name": "relation_properties",
			"type": "STRING",
			"optional": true
		}
	],
	"constraints": [
		["entity", "entity"]
	]
}

[spasserby]

PR: #430