How can we change the configuration of the replica set?

1.	How can we change the configuration of the replica set?
Answer» Loading every DOCUMENT into RAM means that QUERY will not be using index efficiently and will have to FETCH documents from disk to ram. For using an index, the initial match in the FIND statement should either use index or index prefix. Below query has b key to find that does not use any existing index or index prefix so it would have to fetch from disk. db.sample.find( { b : 1 } ).sort( { C : 1, a : 1 } )

Answer»

Loading every DOCUMENT into RAM means that QUERY will not be using index efficiently and will have to FETCH documents from disk to ram.

For using an index, the initial match in the FIND statement should either use index or index prefix.

Below query has b key to find that does not use any existing index or index prefix so it would have to fetch from disk.

db.sample.find( { b : 1 } ).sort( { C : 1, a : 1 } )

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