If the rlimit.rlim_cur value returned by getrlimit is not the
RLIM_INFINITY magic constant, but a *very* large number, we can allocate
too many open files. Restrict set_max_open_files to only return at most
max_file_limit, as passed via its parameter.
The problem was originally stated in
http://bugs.mysql.com/bug.php?id=82212
The size of an base64-encoded Rows_log_event exceeds its
vanilla byte representation in 4/3 times.
When a binlogged event size is about 1GB mysqlbinlog generates
a BINLOG query that can't be send out due to its size.
It is fixed with fragmenting the BINLOG argument C-string into
(approximate) halves when the base64 encoded event is over 1GB size.
The mysqlbinlog in such case puts out
SET @binlog_fragment_0='base64-encoded-fragment_0';
SET @binlog_fragment_1='base64-encoded-fragment_1';
BINLOG @binlog_fragment_0, @binlog_fragment_1;
to represent a big BINLOG.
For prompt memory release BINLOG handler is made to reset the BINLOG argument
user variables in the middle of processing, as if @binlog_fragment_{0,1} = NULL
is assigned.
Notice the 2 fragments are enough, though the client and server still may
need to tweak their @@max_allowed_packet to satisfy to the fragment
size (which they would have to do anyway with greater number of
fragments, should that be desired).
On the lower level the following changes are made:
Log_event::print_base64()
remains to call encoder and store the encoded data into a cache but
now *without* doing any formatting. The latter is left for time
when the cache is copied to an output file (e.g mysqlbinlog output).
No formatting behavior is also reflected by the change in the meaning
of the last argument which specifies whether to cache the encoded data.
Rows_log_event::print_helper()
is made to invoke a specialized fragmented cache-to-file copying function
which is
copy_cache_to_file_wrapped()
that takes care of fragmenting also optionally wraps encoded
strings (fragments) into SQL stanzas.
my_b_copy_to_file()
is refactored to into my_b_copy_all_to_file(). The former function
is generalized
to accepts more a limit argument to constraint the copying and does
not reinitialize anymore the cache into reading mode.
The limit does not do any effect on the fully read cache.
Users expect window functions to produce a certain ordering of rows in
the final result set. Although the standard does not require this, we
already have the filesort result done for when we computed the window
function. If there is no ORDER BY attached to the query, just keep it
till the SELECT is completely evaluated and use that to print the
result.
Update test cases as many did not take care to guarantee a stable
result.
According to logs analysis the Dump thread attempted to read again data which
was already sent. The reason of regressed read turns out in an _my_b_cache_read()
early exit branch which missed to distinguish between total zero size read (e.g
ineffective read when Count argument is zero) from a case when the
requested amount of data is fully read out by sole accessing the cache's
file. In the latter case such then *effective* reading was not
reflected in the cache's state to screw the cache's state.
Fixed with a check introduced of whether the file reading was effective prior to
early exit. When this is the case conduct standard cache state change to
account the actual read size.
Notice the bug can show up also as an error to read binlog event e.g
through BINLOG_GTID_POS() (of MDEV-16886).
This assert is hit when we do filesort using the priority queue and try to insert elements in
the queue. The compare function used for the priority queue should handle the case for zerolength
sortkey.
MySQL bug number 90264
Contribution by Yura Sorokin.
Problem:
File mysys/mf_iocache2.c contains non instrumented file io operations.
This causes inaccurate statistics in PERFORMANCE_SCHEMA.
Solution:
Use the instrumentation apis (mysql_file_tell instead of my_tell, etc).
MEMORY table could be renamed into a non-extistent database.
rename() is documented to return ENOENT when the source file does not
exist OR when the target directory not exist. Nonexistent source .frm
file is ok (table can still exist in the engine), nonexistent target
directory is not.
Make my_rename to use ENOTDIR for the latter case. Make RENAME TABLE
issue an appropriate error ("unknown database" instead of "unknown table")
This previously unreported warning comes from casting size_t to ulong
in sql_hset.h in Hash_Set::at().
Change my_hash_element to accept size_t index parameter.
Also clarify which --{no-,}default* options, must be first.
Sample output:
$ client/mysql --help
client/mysql Ver 15.1 Distrib 5.5.59-MariaDB, for Linux (x86_64) using readline 5.1
Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.
Usage: client/mysql [OPTIONS] [database]
Default options are read from the following files in the given order:
/etc/my.cnf /etc/mysql/my.cnf ~/.my.cnf
The following groups are read: mysql client client-server client-mariadb
The following options may be given as the first argument:
--print-defaults Print the program argument list and exit.
--no-defaults Don't read default options from any option file.
The following specify which files/groups are read (specified before other options):
--defaults-file=# Only read default options from the given file #.
--defaults-extra-file=# Read this file after the global files are read.
--defaults-group-suffix=# Additionally read default groups with # appended as a suffix.
tests running from build directory:
TEST: print defaults ignored as not first
$ sql/mysqld --no-defaults --print-defaults --lc-messages-dir=${PWD}/sql/share
TEST: no startup occurs as --print-defaults specified
$ sql/mysqld --print-defaults --lc-messages-dir=${PWD}/sql/share
sql/mysqld would have been started with the following arguments:
--lc-messages-dir=/home/dan/repos/build-mariadb-5.5/sql/share
TEST: default args can't be anywhere
$ client/mysql --user=bob --defaults-file=/etc/my.cnf
client/mysql: unknown variable 'defaults-file=/etc/my.cnf'
$ client/mysql --user=bob --defaults-group-suffix=.group
client/mysql: unknown variable 'defaults-group-suffix=.group'
/etc/my.cnf:
[client-server.group]
socket=/var/lib/mysql-multi/group/mysqld.sock
user=bob
/etc/my.other.cnf:
socket=/var/lib/mysql-other/mysqld.sock
TEST: defaults file read and suffix also applied
$ client/mysql --defaults-file=/etc/my.other.cnf --defaults-group-suffix=.group
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql-other/mysqld.sock' (2)
TEST: defaults extra file
$ client/mysql --defaults-extra-file=/etc/my.other.cnf --defaults-group-suffix=.group
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql-other/mysqld.sock' (2)
