Marko Mäkelä added a comment - 2023-10-26 13:32 I found a rather simple test case that will crash MySQL 8.0.34 but not MySQL 5.7.43. The code has been refactored between MySQL 5.7 and 8.0. I will need to investigate what exactly has changed between the two versions.

Marko Mäkelä added a comment - 2023-10-27 08:44 In MySQL 5.7.44 with or without the fix , the only way I can reproduce the crash is the following patch: diff --git a/storage/innobase/row/row0ftsort.cc b/storage/innobase/row/row0ftsort.cc index 36ce6eb6cca..03149b68a21 100644 --- a/storage/innobase/row/row0ftsort.cc +++ b/storage/innobase/row/row0ftsort.cc @@ -468,7 +468,7 @@ row_merge_fts_doc_tokenize( row_merge_buf_t* buf; dfield_t* field; fts_string_t t_str; - ibool buf_full = FALSE; + ibool buf_full = TRUE; byte str_buf[FTS_MAX_WORD_LEN + 1]; ulint data_size[FTS_NUM_AUX_INDEX]; ulint n_tuple[FTS_NUM_AUX_INDEX]; But, this will crash also when the fix is present: mysql-5.7.44 with the above patch 2023-10-27 11:28:35 0x7f4c437fe6c0 InnoDB: Assertion failure in thread 139965526697664 in file row0ftsort.cc line 837 InnoDB: Failing assertion: t_ctx.rows_added[t_ctx.buf_used] In MySQL 8.0, the buffer size calculation is quite different. ddl::Context::scan_buffer_size will allocate a buffer by dividing innodb_sort_buffer_size (default: 1MiB) by the number of threads (2 in this case) and index partitions (hard-coded as 6 in the file format). These 54613 bytes will then be passed on to key_buffer.m_buffer_size . It seems that the intention was to round this up to some multiple of 4096 bytes, but that did not happen. Whatever I tried, I am unable to reproduce a crash in MySQL 5.7 with an SQL test case that crashes MySQL 8.0. I think that I must more or less apply the MySQL 5.7 fix without adding a test case. An additional challenge would be that we do not actually have an n-gram tokenizer in MariaDB ( MDEV-10267 ). We only have tests for a simple_parser .