4
我有一个集合中有150万个文档,其索引为“name”字段。像db.things.find({name: /^foo/i})
这样的查询大约需要5秒,这很慢。具有相同记录的相似MySQL表在少于10毫秒内执行SELECT * FROM things WHERE name LIKE 'foo%'
。MongoDB中缓慢的正则表达式查询
蒙戈的解释:
db.things.find({name: /^foo/i}).limit(10).explain()
{
"cursor" : "BtreeCursor name_1 multi",
"nscanned" : 325730,
"nscannedObjects" : 10,
"n" : 10,
"millis" : 4758,
"nYields" : 89,
"nChunkSkips" : 0,
"isMultiKey" : false,
"indexOnly" : false,
"indexBounds" : {
"name" : [
[
"",
{
}
],
[
/^foo/i,
/^foo/i
]
]
}
}
所以是正则表达式查询是缓慢蒙戈还是我做错了?