[dlmarion]

Modified UpgradeUtil to check root, metadata, and user tablet metadata for the existence of write-ahead logs when the user runs the '--prepare' command. If logs are found the user is advised to abort the upgrade and restart the instance to allow tablet recovery.

Assisted-By: OpenAI GPT-6 Luna

[keith-turner]

Putting all the files from different tablets together is not correct and could lead to reading data from a split that is stale and outside a tablets range. The code could be greatly simplified by using the data range on the extent. Tried writing that to see what this would look like and came up with the following. This goes down the tree restricting the range on each child tablet. Found that need to setup the versioning iterator also. Also need to look for tablets with a location or write ahead logs, the manager eventually assigns walogs to tablets assigned to a dead tserver and removes the location. With no live tservers any tablet w/ a location is assigned to a dead tserver.

  private Iterator<TabletMetadata> readChildTablets(TabletMetadata tabletMetadata) {
    var extent = tabletMetadata.getExtent();
    Preconditions.checkState(extent.isMeta());
    String[] files = tabletMetadata.getFiles().stream().map(stf -> stf.getPath().toString())
        .toArray(String[]::new);
    // RFileScanner sets up the system iterator stack by default
    Scanner rfileScanner = RFile.newScanner().from(files)
        .withTableProperties(IteratorConfigUtil.getInitialTableIterators()).build();
    var range = extent.toDataRange().clip(MetadataSchema.TabletsSection.getRange(), true);
    if (range == null) {
      return Collections.emptyIterator();
    }
    rfileScanner.setRange(range);
    RowIterator rowIter = new RowIterator(rfileScanner);
    return Iterators.transform(rowIter,
        ri -> TabletMetadata.convertRow(ri, EnumSet.allOf(TabletMetadata.ColumnType.class), false));
  }

  private void checkTablet(TabletMetadata tm) {
    // TODO throw exception if either is true
    System.out.println(tm.getExtent() + " hasLoc:" + (tm.getLocation() != null) + " hasWals:"
        + (!tm.getLogs().isEmpty()));
  }

  private void checkForDirtyTablets(ClientContext ctx) {
    var rootMeta = TabletsMetadata.getRootMetadata(ctx.getZooKeeperRoot(), ctx.getZooCache());
    checkTablet(rootMeta);
    readChildTablets(rootMeta).forEachRemaining(tm->{
      checkTablet(tm);
      readChildTablets(tm).forEachRemaining(this::checkTablet);
    });
  }

  @Test
  public void test2() throws Exception {
    try (AccumuloClient client = Accumulo.newClient().from(getClientProps()).build()) {
      client.tableOperations().create("table1");
      client.tableOperations().addSplits("table1",
          new TreeSet<>(List.of(new Text("c"), new Text("m"))));
      client.tableOperations().create("table2");
      client.tableOperations().addSplits("table2",
          new TreeSet<>(List.of(new Text("3"), new Text("5"))));
      client.tableOperations().create("table3");
      client.tableOperations().addSplits("table3",
          new TreeSet<>(List.of(new Text("30"), new Text("90"))));

      client.tableOperations().addSplits("accumulo.metadata",
          new TreeSet<>(List.of(new Text("2<"))));

      client.tableOperations().flush("accumulo.metadata", null, null, true);
      client.tableOperations().flush("accumulo.root", null, null, true);

      UtilWaitThread.sleep(1000);

      checkForDirtyTablets((ClientContext) client);
    }
  }

[keith-turner]

May be able to shorten this code by using live tserver set.

[keith-turner]

Once a dirty extent is found should abort, should not read its children as their data will be stale and not include the data in walogs.