Historically, InnoDB split the redo log into at least 2 files.
MDEV-12061 allowed the minimum to be innodb_log_files_in_group=1,
but it kept the default at innodb_log_files_in_group=2.
Because performance seems to be slightly better with only one log file,
and because implementing an append-only variant of the log would require
a single file, let us define the default to be 1, and have
innodb_log_file_size=96M, to retain the same default total size.
Based on the performance testing that was conducted in MDEV-17492,
the InnoDB adaptive hash index could only help performance in specific,
almost-read-only workloads. It could slow down all kinds of workloads
(especially DROP TABLE, TRUNCATE TABLE, ALTER TABLE, or DROP INDEX
operations), and it can become corrupted, causing crashes (such as
MDEV-18815, MDEV-20203) and possibly data corruption. Furthermore,
the adaptive hash index consumes space from the InnoDB buffer pool,
which could hurt performance when the working set would almost fit
in the buffer pool.
Given all this, it is best to disable the adaptive hash index by default.
rec_init_offsets(): Relax the assertion that was added in
commit 01f45becd1
to catch ROW_FORMAT=REDUNDANT records that have fewer fields
than expected.
This assertion would fail when accessing the records of the
built-in InnoDB table SYS_INDEXES. The column MERGE_THRESHOLD
had been effectively instantly added in MariaDB Server 10.2
(and MySQL 5.7), but is_instant() does not hold for that index.
Relax the assertion, so that it will not fail in this case.
The assertion that was added in
commit c0c003beb4
to augment the fix of MDEV-20805 turns out to be invalid when
innodb_immediate_scrub_data_uncompressed is enabled.
In this mode, fsp_init_file_page() will be invoked on data pages
that have been freed, causing writes of almost-all-zero pages.
btr_page_free(): Adjust the comment.
buf_flush_init_for_writing(): Disable the assertion with a note
that it should be re-enabled in MDEV-15528.
This is another follow-up fix to
commit b393e2cb0c
which turned out to be still broken.
Replace the C++11 keyword 'constexpr' with #define.
debug_sync_t::str: Remove the zero-length array.
Replace sync->str with reinterpret_cast<char*>(&sync[1]).
Remove unused variables and type mismatch that was introduced
in commit b393e2cb0c
Also, fix a typo in the documentation of the parameter, and
update the test.
We will remove the InnoDB background operation of merging buffered
changes to secondary index leaf pages. Changes will only be merged as a
result of an operation that accesses a secondary index leaf page,
such as a SQL statement that performs a lookup via that index,
or is modifying the index. Also ROLLBACK and some background operations,
such as purging the history of committed transactions, or computing
index cardinality statistics, can cause change buffer merge.
Encryption key rotation will not perform change buffer merge.
The motivation of this change is to simplify the I/O logic and to
allow crash recovery to happen in the background (MDEV-14481).
We also hope that this will reduce the number of "mystery" crashes
due to corrupted data. Because change buffer merge will typically
take place as a result of executing SQL statements, there should be
a clearer connection between the crash and the SQL statements that
were executed when the server crashed.
In many cases, a slight performance improvement was observed.
This is joint work with Thirunarayanan Balathandayuthapani
and was tested by Axel Schwenke and Matthias Leich.
The InnoDB monitor counter innodb_ibuf_merge_usec will be removed.
On slow shutdown (innodb_fast_shutdown=0), we will continue to
merge all buffered changes (and purge all undo log history).
Two InnoDB configuration parameters will be changed as follows:
innodb_disable_background_merge: Removed.
This parameter existed only in debug builds.
All change buffer merges will use synchronous reads.
innodb_force_recovery will be changed as follows:
* innodb_force_recovery=4 will be the same as innodb_force_recovery=3
(the change buffer merge cannot be disabled; it can only happen as
a result of an operation that accesses a secondary index leaf page).
The option used to be capable of corrupting secondary index leaf pages.
Now that capability is removed, and innodb_force_recovery=4 becomes 'safe'.
* innodb_force_recovery=5 (which essentially hard-wires
SET GLOBAL TRANSACTION ISOLATION LEVEL READ UNCOMMITTED)
becomes safe to use. Bogus data can be returned to SQL, but
persistent InnoDB data files will not be corrupted further.
* innodb_force_recovery=6 (ignore the redo log files)
will be the only option that can potentially cause
persistent corruption of InnoDB data files.
Code changes:
buf_page_t::ibuf_exist: New flag, to indicate whether buffered
changes exist for a buffer pool page. Pages with pending changes
can be returned by buf_page_get_gen(). Previously, the changes
were always merged inside buf_page_get_gen() if needed.
ibuf_page_exists(const buf_page_t&): Check if a buffered changes
exist for an X-latched or read-fixed page.
buf_page_get_gen(): Add the parameter allow_ibuf_merge=false.
All callers that know that they may be accessing a secondary index
leaf page must pass this parameter as allow_ibuf_merge=true,
unless it does not matter for that caller whether all buffered
changes have been applied. Assert that whenever allow_ibuf_merge
holds, the page actually is a leaf page. Attempt change buffer
merge only to secondary B-tree index leaf pages.
btr_block_get(): Add parameter 'bool merge'.
All callers of btr_block_get() should know whether the page could be
a secondary index leaf page. If it is not, we should avoid consulting
the change buffer bitmap to even consider a merge. This is the main
interface to requesting index pages from the buffer pool.
ibuf_merge_or_delete_for_page(), recv_recover_page(): Replace
buf_page_get_known_nowait() with much simpler logic, because
it is now guaranteed that that the block is x-latched or read-fixed.
mlog_init_t::mark_ibuf_exist(): Renamed from mlog_init_t::ibuf_merge().
On crash recovery, we will no longer merge any buffered changes
for the pages that we read into the buffer pool during the last batch
of applying log records.
buf_page_get_gen_known_nowait(), BUF_MAKE_YOUNG, BUF_KEEP_OLD: Remove.
btr_search_guess_on_hash(): Merge buf_page_get_gen_known_nowait()
to its only remaining caller.
buf_page_make_young_if_needed(): Define as an inline function.
Add the parameter buf_pool.
buf_page_peek_if_young(), buf_page_peek_if_too_old(): Add the
parameter buf_pool.
fil_space_validate_for_mtr_commit(): Remove a bogus comment
about background merge of the change buffer.
btr_cur_open_at_rnd_pos_func(), btr_cur_search_to_nth_level_func(),
btr_cur_open_at_index_side_func(): Use narrower data types and scopes.
ibuf_read_merge_pages(): Replaces buf_read_ibuf_merge_pages().
Merge the change buffer by invoking buf_page_get_gen().
buf_flush_init_for_writing(): Assert that FIL_PAGE_TYPE is set
except when creating a new data file with a dummy first page.
buf_dblwr_create(): Ensure that FIL_PAGE_TYPE on all pages
will be initialized. Reset buf_dblwr_being_created at the end.
In the function recv_parse_or_apply_log_rec_body() there are debug checks
for validating the state of the page when redo log records are being
applied. Most notably, FIL_PAGE_TYPE should be set before anything else
is being written to the page.
ibuf_add_free_page(): Set FIL_PAGE_TYPE before performing any other changes.
btr_page_get_split_rec_to_left(): Assert that in the leftmost leaf page,
if the metadata record exists, index->is_instant() must hold.
The assertion of commit 01f45becd1
could fail during innobase_instant_try().
btr_page_get_split_rec_to_left(): Assert that in the leftmost leaf page,
the metadata record exists if and only if index->is_instant().
page_validate(): Correct the wording of a message.
rec_init_offsets(): Assert that whenever a record is in "instant ALTER"
format, index->is_instant() must hold.
In MDEV-11369 (instant ADD COLUMN) in MariaDB Server 10.3,
we introduced the hidden metadata record that must be the
first record in the clustered index if and only if
index->is_instant() holds.
To catch MDEV-19783, in
commit ed0793e096 and
commit 99dc40d6ac
we added some assertions to find cases where
the metadata record is missing while it should not be, or a
record exists when it should not. Those assertions were invalid
when traversing the PAGE_FREE list. That list can contain anything;
we must only be able to determine the successor and the size of
each garbage record in it.
page_validate(), page_simple_validate_old(), page_simple_validate_new():
Do not invoke page_rec_get_next_const() for traversing the PAGE_FREE
list, but instead use a lower-level accessor that does not attempt to
validate the REC_INFO_MIN_REC_FLAG.
page_copy_rec_list_end_no_locks(),
page_copy_rec_list_start(), page_delete_rec_list_start():
Add assertions.
btr_page_get_split_rec_to_left(): Remove a redundant return value,
and make the output parameter the return value.
btr_page_get_split_rec_to_right(), btr_page_split_and_insert(): Clean up.
When MDEV-12026 introduced innodb_checksum_algorithm=full_crc32 in
MariaDB 10.4, it accidentally added a dependency on buf_page_t::encrypted.
Now that the flag has been removed, we must adjust the page-read routine.
buf_page_io_complete(): When the full_crc32 page checksum matches but the
tablespace ID in the page does not match after decrypting, we should
declare it a decryption failure and suppress the page dump output and
any attempts to re-read the page.
Constraint check is done on secondary index update.
F.ex. DELETE does row_upd_sec_index_entry() and checks constraints in
row_upd_check_references_constraints(). UPDATE is optimized for the
case when order is not changed (node->cmpl_info & UPD_NODE_NO_ORD_CHANGE)
and doesn't do row_upd_sec_index_entry(), so it doesn't check constraints.
Since for versioned DELETE we do UPDATE actually, but expect behaviour
of DELETE in terms of constraints, we should deny this optimization to
get constraints checked.
Fix wrong referenced table check when versioned DELETE inserts history in parent
table. Set check_ref to false in this case.
Removed unused dup_chk_only argument for row_ins_sec_index_entry() and
added check_ref argument.
MDEV-18057 fix was superseded by this fix and reverted.
foreign.test:
All key_type combinations: pk, unique, sec(ondary).
btr_cur_pessimistic_delete(): code changed in a way that allows
to put more REC_INFO_MIN_REC_FLAG assertions inside btr_set_min_rec_mark().
Without that change tests innodb.innodb-table-online,
innodb.temp_table_savepoint and innodb_zip.prefix_index_liftedlimit fail.
Removed basically duplicated page_zip_validate() calls
which fails because of temporary(!) invariant violation.
That fixed innodb_zip.wl5522_debug_zip and
innodb_zip.prefix_index_liftedlimit
The bug affects MariaDB Server 10.3 or later, but it makes sense
to improve CHECK TABLE in earlier versions already.
page_validate(): Check REC_INFO_MIN_REC_FLAG in the records.
This allows CHECK TABLE to catch more bugs.
Until now, InnoDB inefficiently compared the aligned fields
FIL_PAGE_PREV, FIL_PAGE_NEXT to the byte-order-agnostic value FIL_NULL.
This is a backport of 32170f8c6d
from MariaDB Server 10.3.
