diff options
Diffstat (limited to 'innobase')
| -rw-r--r-- | innobase/row/row0sel.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/innobase/row/row0sel.c b/innobase/row/row0sel.c index ce6ed091a48..a3744089258 100644 --- a/innobase/row/row0sel.c +++ b/innobase/row/row0sel.c @@ -2702,14 +2702,22 @@ row_search_for_mysql( unique_search_from_clust_index = TRUE; - if (prebuilt->select_lock_type == LOCK_NONE + if (trx->mysql_n_tables_locked == 0 + && prebuilt->select_lock_type == LOCK_NONE && trx->isolation_level > TRX_ISO_READ_UNCOMMITTED && trx->read_view) { /* This is a SELECT query done as a consistent read, and the read view has already been allocated: let us try a search shortcut through the hash - index */ + index. + NOTE that we must also test that + mysql_n_tables_locked == 0, because this might + also be INSERT INTO ... SELECT ... or + CREATE TABLE ... SELECT ... . Our algorithm is + NOT prepared to inserts interleaved with the SELECT, + and if we try that, we can deadlock on the adaptive + hash index semaphore! */ if (btr_search_latch.writer != RW_LOCK_NOT_LOCKED) { /* There is an x-latch request: release |