Accumulo
  1. Accumulo
  2. ACCUMULO-2757 millions of zookeeper watches
  3. ACCUMULO-2969

eliminate table watches in clients by using Thrift to find the table map

    Details

    • Type: Sub-task Sub-task
    • Status: Open
    • Priority: Minor Minor
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: client, master, tserver
    • Labels:
      None

      Description

      Presently, table map information is read directly from zookeeper. This information is pulled using the ZooCache, which adds watches to each table znode, and the name znode. The shell, in particular, pulls table information to provide table names for tab completion.

      It is surprising that clients have watches on znodes for anything but the root tablet and the master's lock/address.

        Activity

        Hide
        Eric Newton added a comment -

        When accumulo began to support table renames, a lot of tablename -> tableid lookups were done in client code. Tables is used for those lookups.

        Given the asynchronous notification of zookeeper, we don't really know the true table state at the moment a change is made.

        How important is it to use zookeeper callbacks to keep the table list current?

        Show
        Eric Newton added a comment - When accumulo began to support table renames, a lot of tablename -> tableid lookups were done in client code. Tables is used for those lookups. Given the asynchronous notification of zookeeper, we don't really know the true table state at the moment a change is made. How important is it to use zookeeper callbacks to keep the table list current?
        Hide
        Sean Busbey added a comment -

        can't we just make the thrift call whenever we need the mapping?

        and maybe a periodic poll for the table name tab completion?

        Show
        Sean Busbey added a comment - can't we just make the thrift call whenever we need the mapping? and maybe a periodic poll for the table name tab completion?
        Hide
        John Vines added a comment -

        How do you plan on handling stale table mappings?

        Show
        John Vines added a comment - How do you plan on handling stale table mappings?

          People

          • Assignee:
            Unassigned
            Reporter:
            Eric Newton
          • Votes:
            0 Vote for this issue
            Watchers:
            2 Start watching this issue

            Dates

            • Created:
              Updated:

              Development