select count(*) from `myoriginalrable`;
select count(*) from `#sql-1e8_11ae5`;
这比比较磁盘上的文件大小要有用得多,因为从MyISAM到InnoDB等的变化会改变行大小。
SHOW ENGINE INNODB STATUS
命令来查找执行 ALTER TABLE 操作的事务,并检查该事务持有多少行锁。这个数字就是已处理的行数。详细解释请参见:http://gabrielcain.com/blog/2009/08/05/mysql-alter-table-and-how-to-observe-progress/
此外,MariaDB 5.3 及更高版本具有报告某些操作(包括 ALTER TABLE)进度的功能。请参阅:这是一个非常老的问题,但至少在mysql 5.7中有了一个恰当的答案。
https://dev.mysql.com/doc/refman/5.7/en/monitor-alter-table-performance-schema.html
简而言之...
UPDATE performance_schema.setup_instruments
SET ENABLED = 'YES'
WHERE NAME LIKE 'stage/innodb/alter%';
UPDATE performance_schema.setup_consumers
SET ENABLED = 'YES'
WHERE NAME LIKE '%stages%';
...运行alter table命令...
SELECT EVENT_NAME, WORK_COMPLETED, WORK_ESTIMATED
FROM performance_schema.events_stages_current;
+------------------------------------------------------+----------------+----------------+
| EVENT_NAME | WORK_COMPLETED | WORK_ESTIMATED |
+------------------------------------------------------+----------------+----------------+
| stage/innodb/alter table (read PK and internal sort) | 280 | 1245 |
+------------------------------------------------------+----------------+----------------+
1 row in set (0.01 sec)
select
beginsd, now(), qRuns, qTime, tName, trxStarted, trxTime, `rows`, modified, locked, hoursLeftL, estimatedEndL, modifiedPerSecL, avgRows, estimatedEndG, modifiedPerSecG, hoursLeftG
from (
select
(@tname:='<table>') tName,
@beginsd:=sysdate() beginsd,
@trxStarted:=(select trx_started from information_schema.innodb_trx where trx_query like concat('alter table %', @tname, '%')) trxStarted,
@trxTime:=timediff(@beginsd, @trxStarted) trxTime,
@rows:=(select table_rows from information_schema.tables where table_name like @tname) `rows`,
@runs:=(ifnull(@runs, 0)+1) qRuns,
@rowsSum:=(ifnull(@rowsSum, 0)+@rows),
round(@avgRows:=(@rowsSum / @runs)) avgRows,
@modified:=(select trx_rows_modified from information_schema.innodb_trx where trx_query like concat('alter table %', @tname, '%')) modified,
@rowsLeftL:=(cast(@rows as signed) - cast(@modified as signed)) rowsLeftL,
round(@rowsLeftG:=(cast(@avgRows as signed) - cast(@modified as signed)), 2) rowsLeftG,
@locked:=(select trx_rows_locked from information_schema.innodb_trx where trx_query like concat('alter table %', @tname, '%')) locked,
@endsd:=sysdate() endsd,
--
time_to_sec(timediff(@endsd, @beginsd)) qTime,
@modifiedInc:=(cast(@modified as signed) - cast(@p_modified as signed)) modifiedInc,
@timeInc:=time_to_sec(timediff(@beginsd, @p_beginsd)) timeInc,
round(@modifiedPerSecL:=(@modifiedInc/@timeInc)) modifiedPerSecL,
round(@modifiedPerSecG:=(@modified/time_to_sec(@trxTime))) modifiedPerSecG,
round(@minutesLeftL := (@rowsLeftL / @modifiedPerSecL / 60)) minutesLeftL,
round(@minutesLeftG := (@rowsLeftG / @modifiedPerSecG / 60)) minutesLeftG,
round(@hoursLeftL := (@minutesLeftL / 60), 2) hoursLeftL,
round(@hoursLeftG := (@minutesLeftG / 60), 2) hoursLeftG,
(@beginsd + INTERVAL @minutesLeftL MINUTE) estimatedEndL,
(@beginsd + INTERVAL @minutesLeftG MINUTE) estimatedEndG,
--
@p_rows:=@rows,
@p_modified:=@modified,
@p_beginsd:=@beginsd
) sq;
运行 ls -laShr /var/lib/mysql | sort -h
命令,您将看到 mysql 文件夹中的文件如下:
最初的回答:
-rw-r----- 1 mysql mysql 3.3G Feb 9 13:21 sql-#2088_10fa.ibd
-rw-r----- 1 mysql mysql 10.2G Feb 9 13:21 posts.ibd
cd /var/lib/mysql/mydb
TABLEFILE="MYTABLE.ibd"
TEMPFILE="\#*ibd"
ls -lah $TABLEFILE;
ls -lah $TEMPFILE; # make sure you have only one temp file or modify the above TEMPFILE
SIZE_TOTAL=$(stat -c %s $TABLEFILE);
# other ways to get 1st size and time
#SIZE1=1550781106; TIME1=1550781106;
#SIZE1=$(stat -c %s $TEMPFILE); TIME1=$(stat -c %Z $TEMPFILE); sleep 10;
SIZE1=0; TIME1=$(stat -c %X $TEMPFILE); # use file create time
echo "SIZE1=$TIME1; TIME1=$TIME1";
SIZE2=$(stat -c %s $TEMPFILE); TIME2=$(stat -c %Z $TEMPFILE);
DELTA_SIZE=$(( $SIZE2 - $SIZE1 ))
DELTA_TIME=$(( $TIME2 - $TIME1 ))
# debug last numbers should not be zero:
echo $SIZE1 $SIZE2 $SIZE_TOTAL $DELTA_SIZE;
echo $TIME1 $TIME2 $DELTA_TIME;
SIZE_PER_SECOND=$( awk "BEGIN {print $DELTA_SIZE / $DELTA_TIME }" );
SIZE_LEFT=$(($SIZE_TOTAL - $SIZE2));
TIME_LEFT_SECONDS=$( awk "BEGIN { print ( $SIZE_LEFT / $SIZE_PER_SECOND) }" );
TIME_LEFT_MINUTES=$( awk "BEGIN { print $TIME_LEFT_SECONDS /60 }" );
TIME_LEFT=$( awk "BEGIN { printf \"%d:%02d:%2d\", int($TIME_LEFT_MINUTES /60), int($TIME_LEFT_MINUTES % 60), int($TIME_LEFT_SECONDS % 60 ) }" );
echo "TIME_LEFT = $TIME_LEFT";
echo "SIZE_LEFT = $SIZE_LEFT" "MB=" $(( $SIZE_LEFT/1024/1024 )) ;
awk "BEGIN { if( $SIZE_TOTAL == $SIZE2 ) print \"mysql finished\" }" ;
free -h # check free memory, sometimes it is full and it makes it slow
结论: 这需要时间,很多时间。
只需确保有可用的内存和空闲空间。 例如,MySQL未使用50%的内存。
低内存会使整个系统运行非常缓慢。
Percona的pt-online-schema-change可以显示剩余时间估计。默认情况下,它每30秒打印一次剩余时间估计和进度百分比。
与仅运行ALTER命令相比,它还具有其他附加功能。
http://www.percona.com/doc/percona-toolkit/2.1/pt-online-schema-change.html
Percona Server是MySQL的一个分支版本,带有一些增强功能,其中就包括此功能。
在SHOW PROCESSLIST中,你可以观察到额外的列,包括ROWS_SENT和ROWS_EXAMINED。例如,如果你的表有1000000条记录,并且你看到了650000的ROWS_EXAMINED,则它已经完成了65%。
请参见http://www.percona.com/doc/percona-server/5.6/diagnostics/process_list.html