What is Ixscan MongoDB?
The root node is the final stage from which MongoDB derives the result set. Stages are descriptive of the operation; e.g. COLLSCAN for a collection scan. IXSCAN for scanning index keys. FETCH for retrieving documents.
How do you identify a query performing a full scan on MongoDB?
The only foolproof method of determining whether a collection scan was performed is to compare the index keys with the match criteria from the query.
How does MongoDB find work?
MongoDB uses multikey indexes to index the content stored in arrays. If you index a field that holds an array value, MongoDB creates separate index entries for every element of the array. These multikey indexes allow queries to select documents that contain arrays by matching on element or elements of the arrays.
What exactly is MongoDB?
MongoDB is an open source NoSQL database management program. NoSQL is used as an alternative to traditional relational databases. NoSQL databases are quite useful for working with large sets of distributed data. MongoDB is a tool that can manage document-oriented information, store or retrieve information.
Is MongoDB owned by Google?
MongoDB was founded in 2007 by Dwight Merriman, Eliot Horowitz and Kevin Ryan – the team behind DoubleClick. At the Internet advertising company DoubleClick (now owned by Google), the team developed and used many custom data stores to work around the shortcomings of existing databases.
Can you do a scan and seek in MongoDB?
Yes MongoDB can do index seek and index scan, but it can do both during one fetch. That is what happened in your case. If started with a seek to the leftmost record of your index cuisine_1 and did a scan on 25359 keys.
What does collscan mean in MongoDB Compass?
Below the Query Performance Summary, MongoDB Compass displays the COLLSCAN query stage to indicate that a collection scan was used for this query. Collection scans indicate that the mongod had to scan the entire collection document by document to identify the results.
How does the explain command work in MongoDB?
To return information on query plans and execution statistics of the query plans, MongoDB provides: the explain command. The explain results present the query plans as a tree of stages. Each stage passes its results (i.e. documents or index keys) to the parent node.
What does keysexamined mean in the MongoDB manual?
For query execution stages that scan an index (e.g. IXSCAN), keysExamined is the total number of in-bounds and out-of-bounds keys that are examined in the process of the index scan. If the index scan consists of a single contiguous range of keys, only in-bounds keys need to be examined.