What is Mapper in Hadoop?

253

---

What is Reducer in Hadoop?

252

---

What are the most common InputFormats in Hadoop?

300

---

Explain InputSplit in Hadoop?

239

---

What is the purpose of RecordReader in hadoop?

234

---

What is Combiner in Hadoop?

257

---

If no custom partitioner is defined in Hadoop then how is data partitioned before it is sent to the reducer?

242

---

Why aggregation cannot be done in Mapper?

304

---

Explain map-only job?

278

---

What is KeyValueTextInputFormat in Hadoop?

266

---

What happen if number of reducer is set to 0 in Hadoop?

245

---

What is TextInputFormat in Hadoop?

235

---

What is purpose of RecordWriter in Hadoop?

287

---

What are the most common OutputFormat in Hadoop?

304

---

What is LazyOutputFormat in Hadoop?

270

---