MongoDB Indizes

username: benji password: 9WKKjL2RQEVJrz

command: mongosh "mongodb+srv://indezes.ggpglwf.mongodb.net/" --apiVersion 1 --username benji

complete connection url: mongodb+srv://benji:9WKKjL2RQEVJrz@indezes.ggpglwf.mongodb.net/

Copy sample data

Clone museum and tweets collections

the server url: mongodb+srv://dbi5.4e2bjau.mongodb.net/ with the password 5hif

cloning the data can be done with the mongodb atls:

Propose, implement, and compare single-field and compound indexes.

1) Single-field index on properties.NAME in museum collection

db.museum.createIndex({ "properties.NAME": 1 })

explain query without index:

db.museum.find({ "properties.NAME": "Kunsthalle Wien" }).explain("executionStats")

{ explainVersion: '1', queryPlanner: { namespace: 'test.museum', parsedQuery: { 'properties.NAME': { '$eq': 'Kunsthalle Wien' } }, indexFilterSet: false, optimizationTimeMillis: 0, maxIndexedOrSolutionsReached: false, maxIndexedAndSolutionsReached: false, maxScansToExplodeReached: false, prunedSimilarIndexes: false, winningPlan: { isCached: false, stage: 'EOF' }, rejectedPlans: [] }, executionStats: { executionSuccess: true, nReturned: 0, executionTimeMillis: 0, totalKeysExamined: 0, totalDocsExamined: 0, executionStages: { isCached: false, stage: 'EOF', nReturned: 0, executionTimeMillisEstimate: 0, works: 1, advanced: 0, needTime: 0, needYield: 0, saveState: 0, restoreState: 0, isEOF: 1 } }, queryShapeHash: 'FA50D32ADB6FD3F086DA0FB6280DF319E5216E0314588B17A803BDD28509AFCC', command: { find: 'museum', filter: { 'properties.NAME': 'Kunsthalle Wien' }, '$db': 'test' }, serverInfo: { host: 'ac-mcb8f3l-shard-00-01.ggpglwf.mongodb.net', port: 27017, version: '8.0.15', gitVersion: 'f79b970f08f60c41491003cd55a3dd459a279c39' }, serverParameters: { internalQueryFacetBufferSizeBytes: 104857600, internalQueryFacetMaxOutputDocSizeBytes: 104857600, internalLookupStageIntermediateDocumentMaxSizeBytes: 16793600, internalDocumentSourceGroupMaxMemoryBytes: 104857600, internalQueryMaxBlockingSortMemoryUsageBytes: 33554432, internalQueryProhibitBlockingMergeOnMongoS: 0, internalQueryMaxAddToSetBytes: 104857600, internalDocumentSourceSetWindowFieldsMaxMemoryBytes: 104857600, internalQueryFrameworkControl: 'trySbeRestricted', internalQueryPlannerIgnoreIndexWithCollationForRegex: 1 }, ok: 1, '$clusterTime': { clusterTime: Timestamp({ t: 1762517196, i: 11 }), signature: { hash: Binary.createFromBase64('QW7klKki0ttsqnPJv2PEXg7OWVk=', 0), keyId: Long('7528846600647475265') } }, operationTime: Timestamp({ t: 1762517196, i: 11 }) }

Important fields:

• winningPlan: COLLSCAN
• totalDocsExamined: 6319

explain query with index:

db.museum.find({ "properties.NAME": "Kunsthalle Wien" }).explain("executionStats")

Comparison

• without index: COLLSCAN, 6319 documents examined
• with index: IXSCAN, 1 document examined