HBASE-29877. Introduce new LTT parameter --timeline to control timeline consistency in read operations (#7723)

Author: anmolnar

hbase-mapreduce/src/test/java/org/apache/hadoop/hbase/util/LoadTestTool.java

@@ -172,6 +172,10 @@ public class LoadTestTool extends AbstractHBaseTool {
   protected static final String OPT_REGION_REPLICA_ID_USAGE =
     "Region replica id to do the reads from";
 
+  public static final String OPT_TIMELINE_CONSISTENCY = "timeline";
+  protected static final String OPT_TIMELINE_CONSISTENCY_USAGE =
+    "Use TIMELINE consistency in read operations. Leave region_replica_id unset, otherwise it will override this setting.";
+
   public static final String OPT_MOB_THRESHOLD = "mob_threshold";
   protected static final String OPT_MOB_THRESHOLD_USAGE =
     "Desired cell size to exceed in bytes that will use the MOB write path";
@@ -227,6 +231,7 @@ public class LoadTestTool extends AbstractHBaseTool {
   private int numRegionsPerServer = DEFAULT_NUM_REGIONS_PER_SERVER;
   private int regionReplication = -1; // not set
   private int regionReplicaId = -1; // not set
+  private boolean timelineConsistency = false;
 
   private int mobThreshold = -1; // not set
 
@@ -360,6 +365,7 @@ protected void addOptions() {
     addOptWithArg(OPT_NUM_REGIONS_PER_SERVER, OPT_NUM_REGIONS_PER_SERVER_USAGE);
     addOptWithArg(OPT_REGION_REPLICATION, OPT_REGION_REPLICATION_USAGE);
     addOptWithArg(OPT_REGION_REPLICA_ID, OPT_REGION_REPLICA_ID_USAGE);
+    addOptNoArg(OPT_TIMELINE_CONSISTENCY, OPT_TIMELINE_CONSISTENCY_USAGE);
     addOptWithArg(OPT_MOB_THRESHOLD, OPT_MOB_THRESHOLD_USAGE);
   }
 
@@ -519,6 +525,11 @@ protected void processOptions(CommandLine cmd) {
     if (cmd.hasOption(OPT_REGION_REPLICA_ID)) {
       regionReplicaId = Integer.parseInt(cmd.getOptionValue(OPT_REGION_REPLICA_ID));
     }
+
+    timelineConsistency = false;
+    if (cmd.hasOption(OPT_TIMELINE_CONSISTENCY)) {
+      timelineConsistency = true;
+    }
   }
 
   private void parseColumnFamilyOptions(CommandLine cmd) {
@@ -705,6 +716,7 @@ protected int loadTable() throws IOException {
       readerThreads.setKeyWindow(keyWindow);
       readerThreads.setMultiGetBatchSize(multiGetBatchSize);
       readerThreads.setRegionReplicaId(regionReplicaId);
+      readerThreads.setTimelineConsistency(timelineConsistency);
     }
 
     if (isUpdate && isWrite) {

hbase-server/src/test/java/org/apache/hadoop/hbase/util/MultiThreadedReader.java

@@ -76,6 +76,7 @@ public class MultiThreadedReader extends MultiThreadedAction {
   private int keyWindow = DEFAULT_KEY_WINDOW;
   private int batchSize = DEFAULT_BATCH_SIZE;
   private int regionReplicaId = -1; // particular region replica id to do reads against if set
+  private boolean timelineConsistency = false;
 
   public MultiThreadedReader(LoadTestDataGenerator dataGen, Configuration conf, TableName tableName,
     double verifyPercent) throws IOException {
@@ -104,6 +105,10 @@ public void setRegionReplicaId(int regionReplicaId) {
     this.regionReplicaId = regionReplicaId;
   }
 
+  public void setTimelineConsistency(boolean timelineConsistency) {
+    this.timelineConsistency = timelineConsistency;
+  }
+
   @Override
   public void start(long startKey, long endKey, int numThreads) throws IOException {
     super.start(startKey, endKey, numThreads);
@@ -318,6 +323,8 @@ protected Get createGet(long keyToRead) throws IOException {
       get = dataGenerator.beforeGet(keyToRead, get);
       if (regionReplicaId > 0) {
         get.setReplicaId(regionReplicaId);
+      }
+      if (timelineConsistency) {
         get.setConsistency(Consistency.TIMELINE);
       }
       if (verbose) {