Zaidi ya single-field indexes za msingi, MongoDB hutoa mikakati ya hali ya juu ya indexing — mpangilio wa compound index (kanuni ya ESR), covered queries, partial/sparse indexes, TTL indexes, na zaidi — ambazo huathiri sana utendaji wa query. Kuzimiliki ni muhimu kwa kuboresha MongoDB katika kiwango kikubwa.
For a compound index supporting a query with Equality, Sort, and Range conditions,
order the fields: EQUALITY → SORT → RANGE (the ESR rule).
// query: status = "active" (equality), sort by date (sort), age > 21 (range)
db.users.createIndex({ status: 1, date: 1, age: 1 }); // E, S, R order
db.users.find({ status: "active", age: { $gt: 21 } }).sort({ date: 1 });
// → the index serves equality match, sorted output, and range scan efficiently
Kanuni ya ESR (mpangilio wa fields: Equality, Sort, Range) hujenga compound indexes zinazohudumia sehemu za filter, sort, na range za query kwa ufanisi — mbinu muhimu ya uboreshaji.
// if a query's filter AND returned fields are ALL in the index, no document fetch needed
db.users.createIndex({ email: 1, name: 1 });
db.users.find({ email: "[email protected]" }, { name: 1, _id: 0 }); // COVERED
// → answered entirely from the index (very fast — never touches the documents)
Covered query (fields zote za filter na projected zikiwa katika index) hujibiwa kutoka index pekee — yenye kasi sana, haisomi nyaraka kamwe.
PARTIAL → index only documents matching a filter (smaller, targeted)
createIndex({ email: 1 }, { partialFilterExpression: { active: true } })
SPARSE → index only documents that HAVE the field (skip missing)
TTL → auto-delete documents after a time (sessions, logs, temp data)
createIndex({ createdAt: 1 }, { expireAfterSeconds: 3600 })
UNIQUE → enforce uniqueness (can combine with partial)
MULTIKEY → automatic for array fields (indexes each element)
WILDCARD → index unknown/arbitrary field names ({ "$**": 1 })
HASHED → for hashed sharding / even distribution
✓ explain("executionStats") → verify index use (IXSCAN), check docs examined vs returned
✓ $indexStats → find UNUSED indexes (remove them — they slow writes for no benefit)
✓ Atlas Performance Advisor → suggests indexes based on actual query patterns
✓ Balance: enough indexes for reads, not so many that writes suffer
Mikakati ya hali ya juu ya indexing ni maarifa ya thamani ya kiwango cha senior kwa kuboresha utendaji wa MongoDB katika kiwango kikubwa, yakijengwa juu ya indexing ya msingi.
Ingawa indexes za msingi husaidia, kumiliki mikakati ya hali ya juu ndiyo kunakotofautisha utendaji wa MongoDB wa kutosha na ule bora.
Kanuni ya ESR (kupanga fields za compound index kama Equality, Sort, Range) ni mbinu muhimu ya kujenga compound indexes zinazohudumia kwa ufanisi sehemu za filter, sort, na range za query pamoja — uboreshaji unaotumika mara kwa mara ambao si dhahiri bila kujua kanuni. Covered queries (ambapo fields zote za filter na zinazorudishwa ziko katika index, hivyo query hujibiwa kutoka index pekee bila kusoma nyaraka) hutoa kasi kubwa kwa queries zenye reads nyingi — mbinu yenye nguvu.
Kujua aina maalum za index — partial (kuindex nyaraka zinazolingana tu, ndogo na zilizolengwa), sparse (nyaraka zilizo na field tu), TTL (data inayokwisha kiotomatiki, bora kwa sessions/logs/temp data), wildcard (kwa field names zisizojulikana), multikey (otomatiki kwa arrays), na unique — kunakuruhusu kuchagua index sahihi kwa kila hali, kuboresha storage na gharama ya write huku ukihudumia queries.
Nidhamu ya uchanganuzi na udumishaji (kutumia explain() kuthibitisha matumizi na ufanisi wa index, $indexStats kupata na kuondoa indexes zisizotumika zinazochelewesha writes bila lazima, na zana kama Atlas Performance Advisor) ni muhimu kwa kuweka indexing yenye ufanisi kwa muda.
Kwa kuwa indexing ndiyo nyenzo yenye athari zaidi ya utendaji wa MongoDB, na kwa kuwa mikakati ya hali ya juu (mpangilio wa ESR wa compound, covered queries, aina maalum za index, na udumishaji) ndiyo inayouboresha katika kiwango kikubwa, kuelewa mikakati ya hali ya juu ya indexing ni maarifa ya thamani ya kiwango cha senior kwa MongoDB yenye utendaji wa juu, mada inayoonyesha utaalamu wa kina wa uboreshaji unaotarajiwa kwa nafasi za senior na eneo ambapo mbinu kama kanuni ya ESR na covered queries hutoa faida kubwa na za kivitendo za utendaji.