[HBASE-17140] Reduce meta request number by skipping table state check

• Type: Improvement
• Status: Patch Available
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.0.0
• Component/s: Client
• Assignee: Guanghao Zhang
• Reporter: Guanghao Zhang
• Created: 21/Nov/16 09:00
• Updated: 30/Nov/16 04:21

Description

Now when request for a disabled table, it need 3 rpc calls before fail.
1. get region location
2. send call to rs and get NotServeRegionException
3. retry and check the table state, then throw TableNotEnabledException

The table state check is added for disabled table. But now the prepare method in RegionServerCallable shows that all retry request will get table state first.

public void prepare(final boolean reload) throws IOException {
    // check table state if this is a retry
    if (reload && !tableName.equals(TableName.META_TABLE_NAME) &&
        getConnection().isTableDisabled(tableName)) {
      throw new TableNotEnabledException(tableName.getNameAsString() + " is disabled.");
    }
    try (RegionLocator regionLocator = connection.getRegionLocator(tableName)) {
      this.location = regionLocator.getRegionLocation(row);
    }
    if (this.location == null) {
      throw new IOException("Failed to find location, tableName=" + tableName +
          ", row=" + Bytes.toString(row) + ", reload=" + reload);
    }
    setStubByServiceName(this.location.getServerName());
}

An improvement is set the region offline in HRegionInfo and throw the RegionOfflineException when get region location. Then we don't need check table state for any retry request.

Review board: https://reviews.apache.org/r/54071/