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delta lake

基本使用 可参见： https://docs.delta.io/2.3.0/quick-start.html#language-scala

bin/spark-shell --packages io.delta:delta-core_2.12:2.3.0 --conf "spark.sql.extensions=io.delta.sql.DeltaSparkSessionExtension" --conf "spark.sql.catalog.spark_catalog=org.apache.spark.sql.delta.catalog.DeltaCatalog"

Note：–packages 会缓存依赖在 本地 ~/.ivy2/cache

$ ll ~/.ivy2/cache/io.delta/delta-core_2.12/jars/delta-core_2.12-2.3.0.jar
-rw-rw-r-- 1 hadoop hadoop 3986365 Apr  5  2023 /home/hadoop/.ivy2/cache/io.delta/delta-core_2.12/jars/delta-core_2.12-2.3.0.jar

val data = spark.range(0, 5)
data.write.format("delta").save("/tmp/delta-table")

val df = spark.read.format("delta").load("/tmp/delta-table")
df.show()

val data = spark.range(5, 10)
data.write.format("delta").mode("overwrite").save("/tmp/delta-table")
df.show()

import io.delta.tables._
import org.apache.spark.sql.functions._

val deltaTable = DeltaTable.forPath("/tmp/delta-table")

// Update every even value by adding 100 to it
deltaTable.update(
  condition = expr("id % 2 == 0"),
  set = Map("id" -> expr("id + 100")))

// Delete every even value
deltaTable.delete(condition = expr("id % 2 == 0"))

// Upsert (merge) new data
val newData = spark.range(0, 20).toDF

deltaTable.as("oldData")
  .merge(
    newData.as("newData"),
    "oldData.id = newData.id")
  .whenMatched
  .update(Map("id" -> col("newData.id")))
  .whenNotMatched
  .insert(Map("id" -> col("newData.id")))
  .execute()

deltaTable.toDF.show()