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  1. MariaDB Server
  2. MDEV-28668

Recovery or backup of INSERT may be incorrect

Details

    Description

      mleich produced rr record traces where a child page number in a B-tree record was recovered incorrectly. The culprit seems to be an overzealous optimization:

      diff --git a/storage/innobase/page/page0cur.cc b/storage/innobase/page/page0cur.cc
      		 
      index dc740cad862..d37d3d85f96 100644
      		 
      --- a/storage/innobase/page/page0cur.cc
      		 
      +++ b/storage/innobase/page/page0cur.cc
      		 
      @@ -1579,8 +1579,12 @@ page_cur_insert_rec_low(
      		 
           const byte *r= rec;
      		 
           const byte *c= cur->rec;
      		 
           const byte *c_end= cur->rec + data_size;
      		 
      +    static_assert(REC_N_OLD_EXTRA_BYTES == REC_N_NEW_EXTRA_BYTES + 1, "");
      		 
           if (c <= insert_buf && c_end > insert_buf)
      		 
             c_end= insert_buf;
      		 
      +    else if (c_end < next_rec &&
      		 
      +             c_end >= next_rec - REC_N_OLD_EXTRA_BYTES + comp)
      		 
      +      c_end= next_rec - REC_N_OLD_EXTRA_BYTES + comp;
      		 
           else
      		 
             c_end= std::min<const byte*>(c_end, block->page.frame + srv_page_size -
      		 
                                          PAGE_DIR - PAGE_DIR_SLOT_SIZE *

      That is, we would compare the bytes of the being-inserted record to some header bytes of next_rec that were just updated by the same function, without them being written to the redo log at all.

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        Issue Links

          is caused by

          Bug - A problem which impairs or prevents the functions of the product. MDEV-21724 Optimize page_cur_insert_rec_low() redo logging

          • Major - Major loss of function.
          • Closed
          relates to

          Bug - A problem which impairs or prevents the functions of the product. MDEV-29438 Recovery or backup of instant ALTER TABLE is incorrect

          • Critical - Crashes, loss of data, severe memory leak.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. MDEV-28312 [FATAL] InnoDB: Page old data size XXX new data size XXX, page old max ins size XXX new max ins size XXX

          • Critical - Crashes, loss of data, severe memory leak.
          • Closed

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              marko Marko Mäkelä
              marko Marko Mäkelä
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                Created:
                Updated:
                Resolved:

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