Strategi indeksing canggih apa sing didukung MongoDB?

Question

Accepted Answer

Saluwaruh indeks singel-field dasar, MongoDB menawarake strategi indeksing canggih — **compound index ordering (ESR rule)**, **covered queries**, **partial/sparse indexes**, **TTL indexes**, lan liyane — sing kritis mpengaruhi performance query. Menguasai dheweke minangka kunci kanggo optimasi MongoDB ing skala gedhe.

## ESR rule kanggo compound indexes

```text
For a compound index supporting a query with Equality, Sort, and Range conditions,
order the fields: EQUALITY → SORT → RANGE (the ESR rule).
```

```js
// 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
```

**ESR rule** (Equality, Sort, Range field order) mbuo compound indexes sing nyayani filter, sort, lan range bagian query kanthi efisien — teknik optimasi utama.

## Covered queries — dilayani sepenuhnya saka indeks

```js
// 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: "ann@x.com" }, { name: 1, _id: 0 });  // COVERED
// → answered entirely from the index (very fast — never touches the documents)
```

**Covered query** (kabèh filter lan projected fields ana ing indeks) dijawab saka indeks piyé — super cepet, ora bakal baca dokumen.

## Tipe indeks khusus

```text
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
```

## Analisis lan pemeliharaan indeks

```text
✓ 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
```

## Mengapa hal ini penting

Strategi indeksing canggih minangka pengetahuan level senior sing berharga kanggo **optimasi performance MongoDB ing skala gedhe**, bangun ing indeksing dasar.

Bentuk indeks dasar mbantu, menguasai strategi canggih minangka apa sing misahake adequate saka excellent MongoDB performance.

**ESR rule** (ordering compound index fields minangka Equality, Sort, Range) minangka teknik utama kanggo mbuo compound indexes sing nyayani filter, sort, lan range kondisi query bebarengan kanthi efisien — optimasi sing sering dilamaké nanging ora jelas tanpa ngerti rule. **Covered queries** (endi semua filter lan field sing dibalekno ana ing indeks, dadi query dijawab saka indeks piyé tanpa baca dokumen) nyedhiyakake kecepatan dramatis kanggo read-heavy queries — teknik sing kuat.

Ngerti **tipe indeks khusus** — **partial** (indexing mung dokumen matching, luwih cilik lan targeted), **sparse** (mung dokumen karo field), **TTL** (auto-expiring data, ideaal kanggo sessions/logs/temp data), **wildcard** (kanggo field names sing ora ketang), **multikey** (otomatis kanggo arrays), lan **unique** — ngawonakke sampeyan milih indeks pas kanggo saben skenario, optimasi storage lan write cost sambil nyayani queries.

**Analisis lan pemeliharaan** disiplin (nggunaake `explain()` kanggo verifikasi indeks use lan efisiensi, `$indexStats` kanggo golek lan busak indeks ora dianggo sing needlessly adem writes, lan tools kaya Atlas Performance Advisor) penting kanggo tetep indeksing efektif sajrone wektu.

Karena indeksing minangka MongoDB performance lever paling impactful, lan karena strategi canggih (ESR compound ordering, covered queries, tipe indeks khusus, lan pemeliharaan) minangka apa sing optimasi dheweke ing skala gedhe, paham strategi indeksing canggih minangka pengetahuan level senior sing berharga kanggo high-performance MongoDB, topik demonstrating deep optimization expertise sing dikarepaken kanggo senior roles lan isa endi techniques kaya ESR rule lan covered queries nyedhiyakake gains performance significant, praktis.