From 06c7f493e35dd1d798f44b6920c4b7957d42c4de Mon Sep 17 00:00:00 2001 From: Sergey Petrunya Date: Thu, 13 Nov 2014 13:56:35 +0300 Subject: [PATCH] MDEV-7068: MRR accessing uninitialised bytes, test case failure main.innodb_mrr - Don't call index_reader->interrupt_read() if the index reader has returned all rows that matched its keys. --- sql/multi_range_read.cc | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/sql/multi_range_read.cc b/sql/multi_range_read.cc index bbc287bf239..2479bc3258c 100644 --- a/sql/multi_range_read.cc +++ b/sql/multi_range_read.cc @@ -684,8 +684,19 @@ int Mrr_ordered_rndpos_reader::refill_from_index_reader() rowid_buffer->write_ptr2= (uchar*)&range_info; rowid_buffer->write(); } - - index_reader->interrupt_read(); + + /* + When index_reader_needs_refill=TRUE, this means we've got all of index + tuples for lookups keys that index_reader had. We are not in the middle + of an index read, so there is no need to call interrupt_read. + + Actually, we must not call interrupt_read(), because it could be that we + haven't read a single row (because all index lookups returned + HA_ERR_KEY_NOT_FOUND). In this case, interrupt_read() will cause [harmless] + valgrind warnings when trying to save garbage from table->record[0]. + */ + if (!index_reader_needs_refill) + index_reader->interrupt_read(); /* Sort the buffer contents by rowid */ rowid_buffer->sort((qsort2_cmp)rowid_cmp_reverse, (void*)file);