fixed up lock counting code - Monty's suggestions (70f61985) · Commits · Software / OSDI20 Artifacts / mariadb

Docs/manual.texi

+73 −54

Original line number	Diff line number	Diff line
		@@ -20285,59 +20285,64 @@ The following columns are returned:
		below, though the format and numbers probably differ:

		@example
		+--------------------------+------------+
		+--------------------------+--------+
		\| Variable_name \| Value \|
		+--------------------------+------------+
		+--------------------------+--------+
		\| Aborted_clients \| 0 \|
		\| Aborted_connects \| 0 \|
		\| Bytes_received \| 142160923 \|
		\| Bytes_sent \| 1161910370 \|
		\| Connections \| 30022 \|
		\| Bytes_received \| 629539 \|
		\| Bytes_sent \| 736394 \|
		\| Connections \| 62 \|
		\| Created_tmp_disk_tables \| 0 \|
		\| Created_tmp_tables \| 8988 \|
		\| Created_tmp_tables \| 0 \|
		\| Created_tmp_files \| 0 \|
		\| Delayed_insert_threads \| 0 \|
		\| Delayed_writes \| 0 \|
		\| Delayed_errors \| 0 \|
		\| Flush_commands \| 1 \|
		\| Handler_delete \| 462604 \|
		\| Handler_read_first \| 95882 \|
		\| Handler_read_key \| 27681068 \|
		\| Handler_read_next \| 265008218 \|
		\| Handler_read_prev \| 3022500 \|
		\| Handler_read_rnd \| 36900998 \|
		\| Handler_read_rnd_next \| 252097176 \|
		\| Handler_update \| 16945404 \|
		\| Handler_write \| 66826676 \|
		\| Key_blocks_used \| 14955 \|
		\| Key_read_requests \| 90131960 \|
		\| Key_reads \| 163268 \|
		\| Key_write_requests \| 7573912 \|
		\| Key_writes \| 3780151 \|
		\| Max_used_connections \| 0 \|
		\| Handler_delete \| 0 \|
		\| Handler_read_first \| 1 \|
		\| Handler_read_key \| 9201 \|
		\| Handler_read_next \| 0 \|
		\| Handler_read_prev \| 0 \|
		\| Handler_read_rnd \| 0 \|
		\| Handler_read_rnd_next \| 45 \|
		\| Handler_update \| 5998 \|
		\| Handler_write \| 0 \|
		\| Key_blocks_used \| 407 \|
		\| Key_read_requests \| 27683 \|
		\| Key_reads \| 407 \|
		\| Key_write_requests \| 0 \|
		\| Key_writes \| 0 \|
		\| Max_used_connections \| 60 \|
		\| Not_flushed_key_blocks \| 0 \|
		\| Not_flushed_delayed_rows \| 0 \|
		\| Open_tables \| 0 \|
		\| Open_files \| 0 \|
		\| Open_tables \| 60 \|
		\| Open_files \| 66 \|
		\| Open_streams \| 0 \|
		\| Opened_tables \| 44598 \|
		\| Questions \| 1866024 \|
		\| Opened_tables \| 66 \|
		\| Questions \| 9308 \|
		\| Select_full_join \| 0 \|
		\| Select_full_range_join \| 0 \|
		\| Select_range \| 68187 \|
		\| Select_range \| 0 \|
		\| Select_range_check \| 0 \|
		\| Select_scan \| 31440 \|
		\| Select_scan \| 0 \|
		\| Slave_running \| OFF \|
		\| Slave_open_temp_tables \| 0 \|
		\| Slow_launch_threads \| 0 \|
		\| Slow_queries \| 0 \|
		\| Sort_merge_passes \| 0 \|
		\| Sort_range \| 0 \|
		\| Sort_rows \| 36650500 \|
		\| Sort_scan \| 5298 \|
		\| Threads_cached \| 0 \|
		\| Threads_connected \| 1 \|
		\| Threads_created \| 30022 \|
		\| Threads_running \| 1 \|
		\| Uptime \| 39613 \|
		+--------------------------+------------+
		\| Sort_rows \| 0 \|
		\| Sort_scan \| 0 \|
		\| Table_locks_immediate \| 3183 \|
		\| Table_locks_waited \| 6030 \|
		\| Threads_cached \| 30 \|
		\| Threads_created \| 61 \|
		\| Threads_connected \| 31 \|
		\| Threads_running \| 31 \|
		\| Uptime \| 135 \|
		+--------------------------+--------+
		@end example

		@cindex variables, status
		@@ -20400,6 +20405,12 @@ open by the slave thread
		@item @code{Sort_range} @tab Number of sorts that where done with ranges.
		@item @code{Sort_rows} @tab Number of sorted rows.
		@item @code{Sort_scan} @tab Number of sorts that where done by scanning the table.
		@item @code{Table_locks_immediate} @tab Number of times a table lock was
		acquired immediately. Available after 3.23.33.
		@item @code{Table_locks_waited} @tab Number of times a table lock could not
		be acquired immediately and a wait was needed. If this is high, and you
		have performance problems, you should first optimize your queries, and then
		either split your table(s) or use replication. Available after 3.23.33.
		@item @code{Threads_cached} @tab Number of threads in the thread cache.
		@item @code{Threads_connected} @tab Number of currently open connections.
		@item @code{Threads_created} @tab Number of threads created to handle connections.
		@@ -40814,6 +40825,9 @@ not yet 100 % confident in this code.
		@appendixsubsec Changes in release 3.23.33
		@itemize bullet
		@item
		Added @code{Table_locks_immediate} and @code{Table_locks_waited} status
		variables
		@item
		Fixed bug in replication that broke slave server start with existing
		@code{master.info}. This fixes a bug introduced in 3.23.32.
		@item
		@@ -46638,10 +46652,15 @@ for @code{BDB} tables. @xref{Internal locking}. With @code{MyISAM}
		tables one can freely mix @code{INSERT} and @code{SELECT} without locks
		(@code{Versioning}).

		Starting in version 3.23.33, you can analyze the table lock contention
		on your system by checkining @code{Table_locks_waited} and
		@code{Table_locks_immediate} environemt variables.

		Some database users claim that @strong{MySQL} cannot support near the
		number of concurrent users because it lacks row-level locking. This is
		a may be true for some specific applications, but is' not generally
		true. As always this depends totally on what the application does and what is the access/update pattern of the data.
		true. As always this depends totally on what the application does and what
		is the access/update pattern of the data.

		Pros for row locking:

include/thr_lock.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -27,6 +27,7 @@ extern "C" {
		#include <my_list.h>

		struct st_thr_lock;
		extern ulong locks_immediate,locks_waited ;

		enum thr_lock_type { TL_IGNORE=-1,
		TL_UNLOCK, /* UNLOCK ANY LOCK */

mysql-test/r/rpl000018.result

0 → 100644

+5 −0

Original line number	Diff line number	Diff line
		Log_name
		master-bin.001
		master-bin.002
		n
		3351

mysql-test/r/status.result

+2 −2

Original line number	Diff line number	Diff line
		Variable_name Value
		Table_locks_immediate 5
		Table_locks_immediate 0
		Table_locks_waited 0
		Variable_name Value
		Table_locks_immediate 8
		Table_locks_immediate 3
		Table_locks_waited 1

mysql-test/std_data/master-bin.001

0 → 100644

+113 B

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Original line number	Diff line number	Diff line
		@@ -20285,59 +20285,64 @@ The following columns are returned:
		below, though the format and numbers probably differ:

		@example
		+--------------------------+------------+
		+--------------------------+--------+
		\| Variable_name \| Value \|
		+--------------------------+------------+
		+--------------------------+--------+
		\| Aborted_clients \| 0 \|
		\| Aborted_connects \| 0 \|
		\| Bytes_received \| 142160923 \|
		\| Bytes_sent \| 1161910370 \|
		\| Connections \| 30022 \|
		\| Bytes_received \| 629539 \|
		\| Bytes_sent \| 736394 \|
		\| Connections \| 62 \|
		\| Created_tmp_disk_tables \| 0 \|
		\| Created_tmp_tables \| 8988 \|
		\| Created_tmp_tables \| 0 \|
		\| Created_tmp_files \| 0 \|
		\| Delayed_insert_threads \| 0 \|
		\| Delayed_writes \| 0 \|
		\| Delayed_errors \| 0 \|
		\| Flush_commands \| 1 \|
		\| Handler_delete \| 462604 \|
		\| Handler_read_first \| 95882 \|
		\| Handler_read_key \| 27681068 \|
		\| Handler_read_next \| 265008218 \|
		\| Handler_read_prev \| 3022500 \|
		\| Handler_read_rnd \| 36900998 \|
		\| Handler_read_rnd_next \| 252097176 \|
		\| Handler_update \| 16945404 \|
		\| Handler_write \| 66826676 \|
		\| Key_blocks_used \| 14955 \|
		\| Key_read_requests \| 90131960 \|
		\| Key_reads \| 163268 \|
		\| Key_write_requests \| 7573912 \|
		\| Key_writes \| 3780151 \|
		\| Max_used_connections \| 0 \|
		\| Handler_delete \| 0 \|
		\| Handler_read_first \| 1 \|
		\| Handler_read_key \| 9201 \|
		\| Handler_read_next \| 0 \|
		\| Handler_read_prev \| 0 \|
		\| Handler_read_rnd \| 0 \|
		\| Handler_read_rnd_next \| 45 \|
		\| Handler_update \| 5998 \|
		\| Handler_write \| 0 \|
		\| Key_blocks_used \| 407 \|
		\| Key_read_requests \| 27683 \|
		\| Key_reads \| 407 \|
		\| Key_write_requests \| 0 \|
		\| Key_writes \| 0 \|
		\| Max_used_connections \| 60 \|
		\| Not_flushed_key_blocks \| 0 \|
		\| Not_flushed_delayed_rows \| 0 \|
		\| Open_tables \| 0 \|
		\| Open_files \| 0 \|
		\| Open_tables \| 60 \|
		\| Open_files \| 66 \|
		\| Open_streams \| 0 \|
		\| Opened_tables \| 44598 \|
		\| Questions \| 1866024 \|
		\| Opened_tables \| 66 \|
		\| Questions \| 9308 \|
		\| Select_full_join \| 0 \|
		\| Select_full_range_join \| 0 \|
		\| Select_range \| 68187 \|
		\| Select_range \| 0 \|
		\| Select_range_check \| 0 \|
		\| Select_scan \| 31440 \|
		\| Select_scan \| 0 \|
		\| Slave_running \| OFF \|
		\| Slave_open_temp_tables \| 0 \|
		\| Slow_launch_threads \| 0 \|
		\| Slow_queries \| 0 \|
		\| Sort_merge_passes \| 0 \|
		\| Sort_range \| 0 \|
		\| Sort_rows \| 36650500 \|
		\| Sort_scan \| 5298 \|
		\| Threads_cached \| 0 \|
		\| Threads_connected \| 1 \|
		\| Threads_created \| 30022 \|
		\| Threads_running \| 1 \|
		\| Uptime \| 39613 \|
		+--------------------------+------------+
		\| Sort_rows \| 0 \|
		\| Sort_scan \| 0 \|
		\| Table_locks_immediate \| 3183 \|
		\| Table_locks_waited \| 6030 \|
		\| Threads_cached \| 30 \|
		\| Threads_created \| 61 \|
		\| Threads_connected \| 31 \|
		\| Threads_running \| 31 \|
		\| Uptime \| 135 \|
		+--------------------------+--------+
		@end example

		@cindex variables, status
		@@ -20400,6 +20405,12 @@ open by the slave thread
		@item @code{Sort_range} @tab Number of sorts that where done with ranges.
		@item @code{Sort_rows} @tab Number of sorted rows.
		@item @code{Sort_scan} @tab Number of sorts that where done by scanning the table.
		@item @code{Table_locks_immediate} @tab Number of times a table lock was
		acquired immediately. Available after 3.23.33.
		@item @code{Table_locks_waited} @tab Number of times a table lock could not
		be acquired immediately and a wait was needed. If this is high, and you
		have performance problems, you should first optimize your queries, and then
		either split your table(s) or use replication. Available after 3.23.33.
		@item @code{Threads_cached} @tab Number of threads in the thread cache.
		@item @code{Threads_connected} @tab Number of currently open connections.
		@item @code{Threads_created} @tab Number of threads created to handle connections.
		@@ -40814,6 +40825,9 @@ not yet 100 % confident in this code.
		@appendixsubsec Changes in release 3.23.33
		@itemize bullet
		@item
		Added @code{Table_locks_immediate} and @code{Table_locks_waited} status
		variables
		@item
		Fixed bug in replication that broke slave server start with existing
		@code{master.info}. This fixes a bug introduced in 3.23.32.
		@item
		@@ -46638,10 +46652,15 @@ for @code{BDB} tables. @xref{Internal locking}. With @code{MyISAM}
		tables one can freely mix @code{INSERT} and @code{SELECT} without locks
		(@code{Versioning}).

		Starting in version 3.23.33, you can analyze the table lock contention
		on your system by checkining @code{Table_locks_waited} and
		@code{Table_locks_immediate} environemt variables.

		Some database users claim that @strong{MySQL} cannot support near the
		number of concurrent users because it lacks row-level locking. This is
		a may be true for some specific applications, but is' not generally
		true. As always this depends totally on what the application does and what is the access/update pattern of the data.
		true. As always this depends totally on what the application does and what
		is the access/update pattern of the data.

		Pros for row locking: