Comment 4 for bug 917942

Mark -

This is an ut_ad() crash, and we only build with UNIV_DEBUG for debug configurations as of last week or so, thus this might very well be some UNIV_DEBUG fallout too. The mlog_write_initial_log_record_fast() failing assertion already looks suspicious in the context of fake updates: ut_ad(mtr_memo_contains_page(mtr, ptr, MTR_MEMO_PAGE_X_FIX)); I haven't tested the release build yet.

The page_zip_compress_log code is the following. The crashing call is couple of lines below the #if FIL_PAGE_DATA > PAGE_DATA block.

I will investigate this tomorrow.

static
void
page_zip_compress_write_log(
/*========================*/
 const page_zip_des_t* page_zip,/*!< in: compressed page */
 const page_t* page, /*!< in: uncompressed page */
 dict_index_t* index, /*!< in: index of the B-tree node */
 mtr_t* mtr) /*!< in: mini-transaction */
{
 byte* log_ptr;
 ulint trailer_size;

 ut_ad(!dict_index_is_ibuf(index));

 log_ptr = mlog_open(mtr, 11 + 2 + 2);

 if (!log_ptr) {

  return;
 }

 /* Read the number of user records. */
 trailer_size = page_dir_get_n_heap(page_zip->data)
  - PAGE_HEAP_NO_USER_LOW;
 /* Multiply by uncompressed of size stored per record */
 if (!page_is_leaf(page)) {
  trailer_size *= PAGE_ZIP_DIR_SLOT_SIZE + REC_NODE_PTR_SIZE;
 } else if (dict_index_is_clust(index)) {
  trailer_size *= PAGE_ZIP_DIR_SLOT_SIZE
   + DATA_TRX_ID_LEN + DATA_ROLL_PTR_LEN;
 } else {
  trailer_size *= PAGE_ZIP_DIR_SLOT_SIZE;
 }
 /* Add the space occupied by BLOB pointers. */
 trailer_size += page_zip->n_blobs * BTR_EXTERN_FIELD_REF_SIZE;
 ut_a(page_zip->m_end > PAGE_DATA);
#if FIL_PAGE_DATA > PAGE_DATA
# error "FIL_PAGE_DATA > PAGE_DATA"
#endif
 ut_a(page_zip->m_end + trailer_size <= page_zip_get_size(page_zip));

 log_ptr = mlog_write_initial_log_record_fast((page_t*) page,
           MLOG_ZIP_PAGE_COMPRESS,
           log_ptr, mtr);
 mach_write_to_2(log_ptr, page_zip->m_end - FIL_PAGE_TYPE);
 log_ptr += 2;
 mach_write_to_2(log_ptr, trailer_size);
 log_ptr += 2;
 mlog_close(mtr, log_ptr);

 /* Write FIL_PAGE_PREV and FIL_PAGE_NEXT */
 mlog_catenate_string(mtr, page_zip->data + FIL_PAGE_PREV, 4);
 mlog_catenate_string(mtr, page_zip->data + FIL_PAGE_NEXT, 4);
 /* Write most of the page header, the compressed stream and
 the modification log. */
 mlog_catenate_string(mtr, page_zip->data + FIL_PAGE_TYPE,
        page_zip->m_end - FIL_PAGE_TYPE);
 /* Write the uncompressed trailer of the compressed page. */
 mlog_catenate_string(mtr, page_zip->data + page_zip_get_size(page_zip)
        - trailer_size, trailer_size);
}