MDEV-7618 introduced configuration parameter innodb_instrument_semaphores
in MariaDB Server 10.1. The parameter seems to only affect the rw-lock
X-latch acquisition. Extra fields are added to rw_lock_t to remember one
X-latch holder or waiter. These fields are not being consulted or reported
anywhere. This is basically only adding code bloat.
If the intention is to debug hangs or deadlocks, we have better tools for
that in the debug server, and for the non-debug server, core dumps can
reveal a lot. For example, the mini-transaction memo records the
currently held buffer block or index rw-locks, to be released at
mtr_t::commit().
The configuration parameter innodb_instrument_semaphores will be
deprecated in 10.2.5 and removed in 10.3.0.
rw_lock_t: Remove the members lock_name, file_name, line, thread_id
which did not affect any output.
Problem was that implementation merged from 10.1 was incompatible
with InnoDB 5.7.
buf0buf.cc: Add functions to return should we punch hole and
how big.
buf0flu.cc: Add written page to IORequest
fil0fil.cc: Remove unneeded status call and add test is
sparse files and punch hole supported by file system when
tablespace is created. Add call to get file system
block size. Used file node is added to IORequest. Added
functions to check is punch hole supported and setting
punch hole.
ha_innodb.cc: Remove unneeded status variables (trim512-32768)
and trim_op_saved. Deprecate innodb_use_trim and
set it ON by default. Add function to set innodb-use-trim
dynamically.
dberr.h: Add error code DB_IO_NO_PUNCH_HOLE
if punch hole operation fails.
fil0fil.h: Add punch_hole variable to fil_space_t and
block size to fil_node_t.
os0api.h: Header to helper functions on buf0buf.cc and
fil0fil.cc for os0file.h
os0file.h: Remove unneeded m_block_size from IORequest
and add bpage to IORequest to know actual size of
the block and m_fil_node to know tablespace file
system block size and does it support punch hole.
os0file.cc: Add function punch_hole() to IORequest
to do punch_hole operation,
get the file system block size and determine
does file system support sparse files (for punch hole).
page0size.h: remove implicit copy disable and
use this implicit copy to implement copy_from()
function.
buf0dblwr.cc, buf0flu.cc, buf0rea.cc, fil0fil.cc, fil0fil.h,
os0file.h, os0file.cc, log0log.cc, log0recv.cc:
Remove unneeded write_size parameter from fil_io
calls.
srv0mon.h, srv0srv.h, srv0mon.cc: Remove unneeded
trim512-trim32678 status variables. Removed
these from monitor tests.
(Inadequate background LRU flushing for write workloads with InnoDB compression).
If InnoDB compression is used and the workload has writes, the
following situation is possible. The LRU flusher issues an LRU flush
request for an instance. buf_do_LRU_batch decides to perform
unzip_LRU eviction and this eviction might fully satisfy the
request. Then buf_flush_LRU_tail checks the number of flushed pages in
the last iteration, finds it to be zero, and wrongly decides not to
flush that instance anymore.
Fixed by maintaining unzip_LRU eviction counter in struct
flush_counter_t variables, and checking it in buf_flush_LRU_tail when
deciding whether to stop flushing the current instance.
Added test cases for new configuration files to get mysql-test-run suite sys_vars
to pass. Fix some small errors.
