mongo stress test, slow query, execution plan explain

http://blog.csdn.net/yuansen1999/article/details/50542902
http://blog.itpub.net/26230597/viewspace-1103372/ slow query
http://www.mongoing.com/eshu_explain2 execution plan
Stage Meaning

such as explain.queryPlanner.winningPlan.stage and explain.queryPlanner.winningPlan.inputStage, etc.

There are only the following categories in the document.

COLLSCAN

full table scan

IXSCAN

index scan

FETCH

retrieves the specified document

SHARD_MERGE according to the index and merges

the data returned by each shard.

However, according to the information in the source code, I also summarize the following categories that are not in the document ( Commonly used as follows, because it is searched through the source code, there may be some omissions)

SORT

indicates that it is sorted in memory (consistent with the old version of scanAndOrder: true)

LIMIT

uses limit to limit the number of returns

SKIP

uses skip to skip

IDHACK

to query for _id

SHARDING_FILTER

Query sharded data through mongos COUNT

Use db.coll.explain

().count() to

perform count operation The stage of the $or query that does not use the index returns TEXT The stage returns PROJECTION when the full-text index is used to query the stage return when the return field is limited