Revert "[0.5-nexus] Write mock metadata cache data to mappings _meta (o…

…pensearch-project#744)"

This reverts commit b3adf46.

flint-spark-integration/src/main/scala/org/apache/spark/sql/flint/config/FlintSparkConf.scala

@@ -253,10 +253,6 @@ object FlintSparkConf {
     FlintConfig("spark.metadata.accessAWSCredentialsProvider")
       .doc("AWS credentials provider for metadata access permission")
       .createOptional()
-  val METADATA_CACHE_WRITE = FlintConfig("spark.flint.metadataCacheWrite.enabled")
-    .doc("Enable Flint metadata cache write to Flint index mappings")
-    .createWithDefault("true")
-
   val CUSTOM_SESSION_MANAGER =
     FlintConfig("spark.flint.job.customSessionManager")
       .createOptional()
@@ -313,8 +309,6 @@ case class FlintSparkConf(properties: JMap[String, String]) extends Serializable
 
   def monitorMaxErrorCount(): Int = MONITOR_MAX_ERROR_COUNT.readFrom(reader).toInt
 
-  def isMetadataCacheWriteEnabled: Boolean = METADATA_CACHE_WRITE.readFrom(reader).toBoolean
-
   /**
    * spark.sql.session.timeZone
    */

flint-spark-integration/src/main/scala/org/opensearch/flint/spark/FlintSpark.scala

@@ -17,7 +17,6 @@ import org.opensearch.flint.common.scheduler.AsyncQueryScheduler
 import org.opensearch.flint.core.{FlintClient, FlintClientBuilder}
 import org.opensearch.flint.core.metadata.FlintIndexMetadataServiceBuilder
 import org.opensearch.flint.core.metadata.log.FlintMetadataLogServiceBuilder
-import org.opensearch.flint.core.storage.FlintOpenSearchMetadataCacheWriter
 import org.opensearch.flint.spark.FlintSparkIndex.ID_COLUMN
 import org.opensearch.flint.spark.FlintSparkIndexOptions.OptionName._
 import org.opensearch.flint.spark.covering.FlintSparkCoveringIndex
@@ -55,9 +54,6 @@ class FlintSpark(val spark: SparkSession) extends FlintSparkTransactionSupport w
     FlintIndexMetadataServiceBuilder.build(flintSparkConf.flintOptions())
   }
 
-  private val flintMetadataCacheWriteService = new FlintOpenSearchMetadataCacheWriter(
-    flintSparkConf.flintOptions())
-
   private val flintAsyncQueryScheduler: AsyncQueryScheduler = {
     AsyncQuerySchedulerBuilder.build(flintSparkConf.flintOptions())
   }
@@ -119,6 +115,7 @@ class FlintSpark(val spark: SparkSession) extends FlintSparkTransactionSupport w
           throw new IllegalStateException(s"Flint index $indexName already exists")
         }
       } else {
+        val metadata = index.metadata()
         val jobSchedulingService = FlintSparkJobSchedulingService.create(
           index,
           spark,
@@ -130,17 +127,14 @@ class FlintSpark(val spark: SparkSession) extends FlintSparkTransactionSupport w
           .transientLog(latest => latest.copy(state = CREATING))
           .finalLog(latest => latest.copy(state = ACTIVE))
           .commit(latest => {
-            val metadata = latest match {
-              case null => // in case transaction capability is disabled
-                index.metadata()
-              case latestEntry =>
-                logInfo(s"Creating index with metadata log entry ID ${latestEntry.id}")
-                index.metadata().copy(latestId = Some(latestEntry.id))
-            }
-            flintClient.createIndex(indexName, metadata)
-            flintIndexMetadataService.updateIndexMetadata(indexName, metadata)
-            if (isMetadataCacheWriteEnabled) {
-              flintMetadataCacheWriteService.updateMetadataCache(indexName, metadata)
+            if (latest == null) { // in case transaction capability is disabled
+              flintClient.createIndex(indexName, metadata)
+              flintIndexMetadataService.updateIndexMetadata(indexName, metadata)
+            } else {
+              logInfo(s"Creating index with metadata log entry ID ${latest.id}")
+              flintClient.createIndex(indexName, metadata.copy(latestId = Some(latest.id)))
+              flintIndexMetadataService
+                .updateIndexMetadata(indexName, metadata.copy(latestId = Some(latest.id)))
             }
             jobSchedulingService.handleJob(index, AsyncQuerySchedulerAction.SCHEDULE)
           })
@@ -405,10 +399,6 @@ class FlintSpark(val spark: SparkSession) extends FlintSparkTransactionSupport w
     new DataTypeSkippingStrategy().analyzeSkippingIndexColumns(tableName, spark)
   }
 
-  private def isMetadataCacheWriteEnabled: Boolean = {
-    flintSparkConf.isMetadataCacheWriteEnabled
-  }
-
   private def getAllIndexMetadata(indexNamePattern: String): Map[String, FlintMetadata] = {
     if (flintIndexMetadataService.supportsGetByIndexPattern) {
       flintIndexMetadataService
@@ -578,9 +568,6 @@ class FlintSpark(val spark: SparkSession) extends FlintSparkTransactionSupport w
       })
       .commit(_ => {
         flintIndexMetadataService.updateIndexMetadata(indexName, index.metadata)
-        if (isMetadataCacheWriteEnabled) {
-          flintMetadataCacheWriteService.updateMetadataCache(indexName, index.metadata)
-        }
         logInfo("Update index options complete")
         jobSchedulingService.handleJob(index, AsyncQuerySchedulerAction.UPDATE)
       })