It seems that this (LSN delta divided by bitmap size being small) is easy enough to reproduce. Start server with:
innodb_track_changed_pages=1 innodb_max_bitmap_file_size=32768
Then apply load like this:
create table tbig(id int primary key, c1 char(255)) engine=InnoDB; insert into tbig values(1,'a'); insert into tbig select rand()*1000000000, 'a' from tbig; ... insert into tbig select rand()*1000000000, 'a' from tbig; flush changed_page_bitmaps;
and check *.xdb file sizes and LSN values:
openxs@ao756:~/dbs/p5.6$ ls -l data/*.xdb -rw-rw---- 1 openxs openxs 147456 п╩я▌я┌ 3 19:28 data/ib_modified_log_1_0.xdb -rw-rw---- 1 openxs openxs 32768 п╩я▌я┌ 3 19:32 data/ib_modified_log_2_12003768.xdb -rw-rw---- 1 openxs openxs 40960 п╩я▌я┌ 3 19:33 data/ib_modified_log_3_12017366.xdb -rw-rw---- 1 openxs openxs 45056 п╩я▌я┌ 3 19:35 data/ib_modified_log_4_13490670.xdb ...
and do calculations like this:
mysql> select (1349067-1201736)/40960; +-------------------------+ | (1349067-1201736)/40960 | +-------------------------+ | 3.5969 | +-------------------------+ 1 row in set (0,01 sec)
Note low values like the above.
It seems that this (LSN delta divided by bitmap size being small) is easy enough to reproduce. Start server with:
innodb_ track_changed_ pages=1 max_bitmap_ file_size= 32768
innodb_
Then apply load like this:
create table tbig(id int primary key, c1 char(255)) engine=InnoDB; page_bitmaps;
insert into tbig values(1,'a');
insert into tbig select rand()*1000000000, 'a' from tbig;
...
insert into tbig select rand()*1000000000, 'a' from tbig;
flush changed_
and check *.xdb file sizes and LSN values:
openxs@ ao756:~ /dbs/p5. 6$ ls -l data/*.xdb modified_ log_1_0. xdb modified_ log_2_12003768. xdb modified_ log_3_12017366. xdb modified_ log_4_13490670. xdb
-rw-rw---- 1 openxs openxs 147456 п╩я▌я┌ 3 19:28 data/ib_
-rw-rw---- 1 openxs openxs 32768 п╩я▌я┌ 3 19:32 data/ib_
-rw-rw---- 1 openxs openxs 40960 п╩я▌я┌ 3 19:33 data/ib_
-rw-rw---- 1 openxs openxs 45056 п╩я▌я┌ 3 19:35 data/ib_
...
and do calculations like this:
mysql> select (1349067- 1201736) /40960; ------- ------- -----+ 1201736) /40960 | ------- ------- -----+ ------- ------- -----+
+------
| (1349067-
+------
| 3.5969 |
+------
1 row in set (0,01 sec)
Note low values like the above.