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  1. Percona XtraBackup
  2. PXB-576

LP #810269: tar4ibd does not check for doublewrite buffer pages

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    Details

    • Type: Bug
    • Status: Done
    • Priority: High
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: None
    • Labels:

      Description

      **Reported in Launchpad by Alexey Kopytov last update 19-07-2011 07:28:56

      The xtrabackup binary has the following code to skip checksum verification for doublewrite buffer pages:

      "
      #ifndef INNODB_VERSION_SHORT
      if (buf_page_is_corrupted(page + chunk_offset))
      #else
      if (buf_page_is_corrupted(page + chunk_offset, zip_size))
      #endif
      {
      if (
      #ifdef XTRADB_BASED
      trx_sys_sys_space(node->space->id)
      #else
      node->space->id == 0
      #endif
      && ((offset + (IB_INT64)chunk_offset) >> page_size_shift)
      >= FSP_EXTENT_SIZE
      && ((offset + (IB_INT64)chunk_offset) >> page_size_shift)
      < FSP_EXTENT_SIZE * 3) {
      /* double write buffer may have old data in the end
      or it may contain the other format page like COMPRESSED.
      So, we can pass the check of double write buffer.*/
      ut_a(page_size == UNIV_PAGE_SIZE);
      fprintf(stderr, "[%02u] xtrabackup: "
      "Page %lu seems double write "
      "buffer. passing the check.\n",
      thread_n,
      (ulint)((offset +
      (IB_INT64)chunk_offset) >>
      page_size_shift));
      "

      However, tar4ibd does not have this check, so in case of checksum mismatch for such pages, tar4ibd would fail whereas xtrabackup would succeed with a warning.

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              • Assignee:
                Unassigned
                Reporter:
                lpjirasync lpjirasync (Inactive)
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                  Updated:
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