IGNITE-24157 LastArchivedSegment metric for WAL archive

docs/_docs/monitoring-metrics/new-metrics.adoc

@@ -431,6 +431,7 @@ Register name: `io.datastorage`
 |CheckpointTotalTime| long |   Total duration of checkpoint
 |CheckpointWalRecordFsyncHistogram| histogram |   Histogram of the WAL fsync after logging ChTotalNodeseckpointRecord on begin of checkpoint duration in milliseconds.
 |CheckpointWriteEntryHistogram| histogram |   Histogram of entry buffer writing to file duration in milliseconds.
+|LastArchivedSegment | long | Last archived segment index.
 |LastCheckpointBeforeLockDuration|  long |   Duration of the checkpoint action before taken write lock in milliseconds.
 |LastCheckpointCopiedOnWritePagesNumber|  long |   Number of pages copied to a temporary checkpoint buffer during the last checkpoint.
 |LastCheckpointDataPagesNumber|   long  |  Total number of data pages written during the last checkpoint.

modules/core/src/main/java/org/apache/ignite/internal/processors/cache/persistence/DataStorageMetricsImpl.java

@@ -275,6 +275,10 @@ public DataStorageMetricsImpl(
             this::walTotalSize,
             "Total size in bytes for storage wal files.");
 
+        mreg.register("LastArchivedSegment",
+            this::lastArchivedSegment,
+            "Last archived segment index.");
+
         long[] cpBounds = new long[] {100, 500, 1000, 5000, 30000};
 
         cpBeforeLockHistogram = mreg.histogram("CheckpointBeforeLockHistogram", cpBounds,
@@ -362,6 +366,16 @@ private int walArchiveSegments() {
         return walMgr == null ? 0 : walMgr.walArchiveSegments();
     }
 
+    /** @return Last archived segment index. */
+    private long lastArchivedSegment() {
+        if (!metricsEnabled)
+            return -1;
+
+        IgniteWriteAheadLogManager walMgr = this.wal;
+
+        return walMgr == null ? -1 : walMgr.lastArchivedSegment();
+    }
+
     /**
      * @return The average WAL fsync duration in microseconds over the last time interval.
      */

modules/core/src/test/java/org/apache/ignite/internal/processors/cache/persistence/IgniteDataStorageMetricsSelfTest.java

@@ -125,7 +125,8 @@ public class IgniteDataStorageMetricsSelfTest extends GridCommonAbstractTest {
                 .setMaxSize(maxRegionSize)
                 .setPersistenceEnabled(true)
                 .setMetricsEnabled(true)
-                .setName(PERSISTENCE_REGION_1))
+                .setName(PERSISTENCE_REGION_1)
+                .setCdcEnabled(true))
             .setDataRegionConfigurations(
                 new DataRegionConfiguration()
                     .setMaxSize(maxRegionSize)
@@ -538,6 +539,17 @@ private void checkWalArchiveAndTotalSize(IgniteEx igniteEx, boolean hasWalArchiv
             totalSize += walMgr.totalSize(walFiles(router.getWalArchiveDir()));
 
         assertEquals(totalSize, dsMetricRegistry(igniteEx).<LongGauge>findMetric("WalTotalSize").value());
+
+        long lastArchivedSegIdx = dsMetricRegistry(igniteEx).<LongGauge>findMetric("LastArchivedSegment").value();
+
+        if (router.hasArchive()) {
+            long cdcWalArchiveSegments = walFiles(walMgr.walCdcDirectory()).length;
+
+            // Count of segments = LastArchivedSegmentIndex + 1
+            assertEquals(cdcWalArchiveSegments, lastArchivedSegIdx + 1);
+        }
+        else
+            assertEquals(-1, lastArchivedSegIdx);
     }
 
     /**