Like MDEV-28105, spider may attempt to connect to remote server in
info(), and it may emit an error upon failure to connect. In this
case, the downstream caller ha_partition::open() should return the
error to avoid inconsistency.
This fixes MDEV-27186, MDEV-27237, MDEV-27334, MDEV-28241, MDEV-34101.
Spider calls ha_spider::close() at least twice on ALTER TABLE ... ADD
PARTITION. The first call frees wide_handler and the second call
accesses wide_handler->trx->thd (heap-use-after-free).
In general, there seems to be no problem with using THD obtained by
the macro current_thd() except in background threads. Thus, we simply
replace wide_handler->trx->thd with current_thd().
Original author: Nayuta Yanagasawa
A wide_handler is shared among ha_spider of partitions of the same
spider table, where the last partition is designated the owner of the
wide_handler, and is responsible for its deallocation. Therefore in
case of failure, we only reset wide_handler in error handling if the
current ha_spider is the owner of the wide_handler, otherwise it will
result in segv in the destructor of ha_spider, or during
ha_spider::close().
Spider calls info with HA_STATUS_AUTO to update auto increment info,
which may attempt to connect the data node. If the connection fails,
it may emit an error and return the same error. This error should not
be of lower priority than any possible error from the later call to
handler::update_auto_increment().
Without this change, certain errors from update_auto_increment() such
as HA_ERR_AUTOINC_ERANGE may get ignored, causing my_insert() to call
my_ok(), which fails the assertion because the error was emitted in
the info() call (Diagnostics_area::is_set() returns true).
In the absence of insight of the cause of spider.spider_fixes_part
failure as described in MDEV-30929, This is a workaround, which could
help narrow the possibility down to whether slave SQL thread attempts
to read from file that maybe not yet on disk. It does not otherwise
affect the coverage of the test.
I have pushed this commit 4 times, but have yet to encounter the
failure as described in MDEV-30929, so it could also fix the test and
stop the CI pollution.
Also replaced START SLAVE; with --source include/start_slave.inc
inside the slave_test_init.inc files.
UDF isn't supposed to use my_error(), it should return
the error message in the provided error message buffer
Fixes valgrind:
==93993== Conditional jump or move depends on uninitialised value(s)
==93993== at 0x484ECCD: strnlen (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==93993== by 0x1AD2B2C: process_str_arg (my_vsnprintf.c:259)
==93993== by 0x1AD47E0: my_vsnprintf_ex (my_vsnprintf.c:696)
==93993== by 0x1A3B91E: my_error (my_error.c:120)
==93993== by 0xF87BE8: udf_handler::fix_fields(THD*, Item_func_or_sum*, unsigned int, Item**) (item_func.cc:3638)
followup for 267dd5a993
The two I_S plugins SPIDER_ALLOC_MEM and SPIDER_WRAPPER_PROTOCOL
only makes sense if the main SPIDER plugin is installed. Further,
SPIDER_ALLOC_MEM requires a mutex that requires SPIDER init to fill
the table.
We also update the spider init query to override
--transaction_read_only=on so that it does not affect the spider init.
Also fixed error handling in spider_db_init() so that failure in
spider table init does not result in memory leak
Only locked will participate in the query in this case. Chances are
that not-locked partitions were not opened, which is the cause of the
crash in the added test case spider/bugfix.mdev_33731 without this
patch.
The spider group by handler is created in
JOIN::make_aggr_tables_info(), by which time calls to
substitute_for_best_equal_field() should have already removed all the
multiple equalities (i.e. Item_equal, with MULT_EQUAL_FUNC func_type).
Therefore, if there is still such items, it is deemed as an optimizer
bug and should be skipped.
Also removed ITEM_FUNC_TIMESTAMPDIFF_ARE_PUBLIC.
Similar to pr#2225, with the testcase adapted from that patch:
--8<---------------cut here---------------start------------->8---
From 884f7c6df1 Mon Sep 17 00:00:00 2001
From: "Norio Akagi (norakagi)" <norakagi@amazon.com>
Date: Wed, 3 Aug 2022 23:30:34 -0700
Subject: [PATCH] [MDEV-28992] Push down TIMESTAMP_DIFF in spider
This changes so that TIMESTAMP_DIFF function in a query is pushed down and works natively in Spider.
Instead of directly accessing item's member, now we can rely on a public accessor method to make it work.
Unit tests are added under spider.pushdown_timestamp_diff.
All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer
Amazon Web Services, Inc.
--8<---------------cut here---------------end--------------->8---
Some fixes related to commit f838b2d799 and
Rows_log_event::do_apply_event() and Update_rows_log_event::do_exec_row()
for system-versioned tables were provided by Nikita Malyavin.
This was required by test versioning.rpl,trx_id,row.
https://jepsen.io/analyses/mysql-8.0.34 highlights that the
transaction isolation levels in the InnoDB storage engine do not
correspond to any widely accepted definitions, such as
"Generalized Isolation Level Definitions"
https://pmg.csail.mit.edu/papers/icde00.pdf
(PL-1 = READ UNCOMMITTED, PL-2 = READ COMMITTED, PL-2.99 = REPEATABLE READ,
PL-3 = SERIALIZABLE).
Only READ UNCOMMITTED in InnoDB seems to match the above definition.
The issue is that InnoDB does not detect write/write conflicts
(Section 4.4.3, Definition 6) in the above.
It appears that as soon as we implement write/write conflict detection
(SET SESSION innodb_snapshot_isolation=ON), the default isolation level
(SET TRANSACTION ISOLATION LEVEL REPEATABLE READ) will become
Snapshot Isolation (similar to Postgres), as defined in Section 4.2 of
"A Critique of ANSI SQL Isolation Levels", MSR-TR-95-51, June 1995
https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/tr-95-51.pdf
Locking reads inside InnoDB used to read the latest committed version,
ignoring what should actually be visible to the transaction.
The added test innodb.lock_isolation illustrates this. The statement
UPDATE t SET a=3 WHERE b=2;
is executed in a transaction that was started before a read view or
a snapshot of the current transaction was created, and committed before
the current transaction attempts to execute
UPDATE t SET b=3;
If SET innodb_snapshot_isolation=ON is in effect when the second
transaction was started, the second transaction will be aborted with
the error ER_CHECKREAD. By default (innodb_snapshot_isolation=OFF),
the second transaction would execute inconsistently, displaying an
incorrect SELECT COUNT(*) FROM t in its read view.
If innodb_snapshot_isolation=ON, if an attempt to acquire a lock on a
record that does not exist in the current read view is made, an error
DB_RECORD_CHANGED (HA_ERR_RECORD_CHANGED, ER_CHECKREAD) will
be raised. This error will be treated in the same way as a deadlock:
the transaction will be rolled back.
lock_clust_rec_read_check_and_lock(): If the current transaction has
a read view where the record is not visible and
innodb_snapshot_isolation=ON, fail before trying to acquire the lock.
row_sel_build_committed_vers_for_mysql(): If innodb_snapshot_isolation=ON,
disable the "semi-consistent read" logic that had been implemented by
myself on the directions of Heikki Tuuri in order to address
https://bugs.mysql.com/bug.php?id=3300 that was motivated by a customer
wanting UPDATE to skip locked rows that do not match the WHERE condition.
It looks like my changes were included in the MySQL 5.1.5
commit ad126d90e019f223470e73e1b2b528f9007c4532; at that time, employees
of Innobase Oy (a recent acquisition of Oracle) had lost write access to
the repository.
The only reason why we set innodb_snapshot_isolation=OFF by default is
backward compatibility with applications, such as the one that motivated
the implementation of "semi-consistent read" back in 2005. In a later
major release, we can default to innodb_snapshot_isolation=ON.
Thanks to Peter Alvaro, Kyle Kingsbury and Alexey Gotsman for their work
on https://github.com/jepsen-io/ and to Kyle and Alexey for explanations
and some testing of this fix.
Thanks to Vladislav Lesin for the initial test for MDEV-26643,
as well as reviewing these changes.
