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MDEV-33363 CI failure: innodb.import_corrupted: Assertion failed: oldest_lsn > log_sys.last_checkpoint_lsn

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This regression is introduced in MDEV-28708 where the MTR_LOG_NO_REDO
mtrs are assigned last_checkpoint_lsn as the LSN. It causes a race with
checkpoint in pending state. The concurrent checkpoint writes a
checkpoint LSN of larger value after pages with older checkpoint LSN is
inserted into the flush list. The next checkpoint sees the reversal in
checkpoint sequence and asserts if the pages are not yet flushed.

There could be several ways to solve this issue. Ideally the unlogged
mtr should take the latest LSN as opposed to going behind and use the
previous checkpoint LSN. It has been the older design and seems good.
Also, other than the critical race, using the old checkpoint LSN adds
the pages to other end of flush list overriding all existing dirty
pages and looks counter intuitive.
This commit is contained in:
mariadb-DebarunBanerjee 2024-02-16 10:27:58 +05:30
parent 64cce8d5bf
commit 4039d8605d
1 changed files with 8 additions and 1 deletions
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9
storage/innobase/mtr/mtr0mtr.cc
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@ -234,7 +234,14 @@ static void insert_imported(buf_block_t *block)
if (block->page.oldest_modification() <= 1)
{
log_sys.latch.rd_lock(SRW_LOCK_CALL);
const lsn_t lsn= log_sys.last_checkpoint_lsn;
/* For unlogged mtrs (MTR_LOG_NO_REDO), we use the current system LSN. The
mtr that generated the LSN is either already committed or in mtr_t::commit.
Shared latch and relaxed atomics should be fine here as it is guaranteed
that both the current mtr and the mtr that generated the LSN would have
added the dirty pages to flush list before we access the minimum LSN during
checkpoint. log_checkpoint_low() acquires exclusive log_sys.latch before
commencing. */
const lsn_t lsn= log_sys.get_lsn();
mysql_mutex_lock(&buf_pool.flush_list_mutex);
buf_pool.insert_into_flush_list
(buf_pool.prepare_insert_into_flush_list(lsn), block, lsn);