Do as mysqld_safe: if running mysqld-debug, plugins are in debug subdirs
NB mtr --debug won't work in this context until 47141 is fixed
Also moved read_plugin_defs; no point running this in all worker threads
Added --mysqld-env option, propagate via safe_process
Simplified: should be safe to set in parent safe_process after it's started
Addendum: catch cases of --mysqld-env w/o value, assume env.var
name never begins with "--"
that implement add_index
The problem was that ALTER TABLE blocked reads on an InnoDB table
while adding a secondary index, even if this was not needed. It is
only needed for the final step where the .frm file is updated.
The reason queries were blocked, was that ALTER TABLE upgraded the
metadata lock from MDL_SHARED_NO_WRITE (which blocks writes) to
MDL_EXCLUSIVE (which blocks all accesses) before index creation.
The way the server handles index creation, is that storage engines
publish their capabilities to the server and the server determines
which of the following three ways this can be handled: 1) build a
new version of the table; 2) change the existing table but with
exclusive metadata lock; 3) change the existing table but without
metadata lock upgrade.
For InnoDB and secondary index creation, option 3) should have been
selected. However this failed for two reasons. First, InnoDB did
not publish this capability properly.
Second, the ALTER TABLE code failed to made proper use of the
information supplied by the storage engine. A variable
need_lock_for_indexes was set accordingly, but was not later used.
This patch fixes this problem by only doing metadata lock upgrade
before index creation/deletion if this variable has been set.
This patch also changes some of the related terminology used
in the code. Specifically the use of "fast" and "online" with
respect to ALTER TABLE. "Fast" was used to indicate that an
ALTER TABLE operation could be done without involving a
temporary table. "Fast" has been renamed "in-place" to more
accurately describe the behavior.
"Online" meant that the operation could be done without taking
a table lock. However, in the current implementation writes
are always prohibited during ALTER TABLE and an exclusive
metadata lock is held while updating the .frm, so ALTER TABLE
is not completely online. This patch replaces "online" with
"in-place", with additional comments indicating if concurrent
reads are allowed during index creation/deletion or not.
An important part of this update of terminology is renaming
of the handler flags used by handlers to indicate if index
creation/deletion can be done in-place and if concurrent reads
are allowed. For example, the HA_ONLINE_ADD_INDEX_NO_WRITES
flag has been renamed to HA_INPLACE_ADD_INDEX_NO_READ_WRITE,
while HA_ONLINE_ADD_INDEX is now HA_INPLACE_ADD_INDEX_NO_WRITE.
Note that this is a rename to clarify current behavior, the
flag values have not changed and no flags have been removed or
added.
Test case added to innodb_mysql_sync.test.
over the mutex list and free each mutex. When UNIV_MEM_DEBUG is defined, we
need skip the hash mutex.
It is a minor bug affecting only UNIV_SYNC_DEBUG builds, found by Michael.
There are two main pain points, one is lookup by thread id for sync_thread_t
and the other is to do a lookup by latch or level in sync_thread_t::levels.
Changed the sync_thread_t::levels lookup and reserve operation from O(N)
to O(1).
Pure lookups are still O(N), the main change for pure lookup is that we no
longer need to search up to SYNC_THREAD_N_LEVELS but only up to the number
of slots actually ever used ie. it is possible some were used in the past
but are now on the free list. If the in_use count drops to 0 we reset the
free list too.
Overload the sync_level_t::level field to track the free list. If
sync_thread_t::latch == NULL then sync_thread_t::level contains the ordinal
value of the previous free entry.
rb://580 Approved by Jimmy Yang.
Fix for bug#45740 introduced test case using SHOW TABLE STATUS against a Memory table using latin1 character in table name.
The test failed on Windows and FreeBSD due to a difference in the value for Avg_row_length.
The average row length normally depends on the values for data length and row count. According to the 5.5 manual data length is approximate with Memory tables.
With MyISAM and InnoDB the Avg_row_length is the same on Windows and Solaris.
The solution implemented by this patch is to mask out the value for Avg_row_length, as it may vary when using Memory tables.
