只更新需要更新的字段 - 不建议取出整个文档，更新某个字段，然后保存整个文档

避免不存在的查询 - 不存在的字段会导致全表扫描

Use covered queries when possible.

Test every query in your application with explain()

Update multiple array elements in a single operation

Avoid scatter-gather queries

Choose the appropriate write guarantees

Choose the right read-concern

Use causal consistency where needed

Use the most recent drivers from MongoDB

Ensure uniform distribution of shard keys

Use hash-based sharding when appropriate

Avoid large documents

Avoid unnecessarily long fifield names

Use caution when considering indexes on low-cardinality fifields

Eliminate unnecessary indexes

Remove indexes that are prefifixes of other indexes

Use a compound index rather than index intersection

Use partial indexes

Avoid regular expressions that are not left anchored or rooted

Use index optimizations available in the WiredTiger storage engine

Understand any existing document schema – MongoDB Compass

Identify & remove obsolete indexes

Readahead size should be set to 0 for WiredTiger

Use XFS fifile systems; avoid EXT3

Disable access time settings

Don’t use Huge Pages

Use RAID10

Use multiple devices for different databases – WiredTiger.

Implement multi-temperature storage & data locality using MongoDB Zones