diff options
| -rw-r--r-- | storage/innodb_plugin/row/row0sel.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/storage/innodb_plugin/row/row0sel.c b/storage/innodb_plugin/row/row0sel.c index 241584eaa20..aa3f6283c4f 100644 --- a/storage/innodb_plugin/row/row0sel.c +++ b/storage/innodb_plugin/row/row0sel.c @@ -63,7 +63,13 @@ Created 12/19/1997 Heikki Tuuri /* Number of rows fetched, after which to start prefetching; MySQL interface has another parameter */ -#define SEL_PREFETCH_LIMIT 1 +/* The prefetch code in the internal SQL is disabled because it has probably +never been used and has been found to contain a memory leak and a bug of +accessing uninitialized memory. Some simple performance tests show that +disabling it makes no difference in performance. It will be removed, but +until the removal happens we disable it by setting SEL_PREFETCH_LIMIT to a +high value. */ +#define SEL_PREFETCH_LIMIT 1000000000 /* When a select has accessed about this many pages, it returns control back to que_run_threads: this is to allow canceling runaway queries */ |