Details
-
Bug
-
Status: In Progress (View Workflow)
-
Critical
-
Resolution: Unresolved
-
10.7, 10.8, 10.9, 10.10, 10.11, 11.0, 11.1, 11.2, 11.3, 11.4
Description
As noted in MDEV-26740, ALTER TABLE...ALGORITHM=COPY fails to make use of the MDEV-24621 optimization to pre-sort each index and to build them page by page.
I tested this on MariaDB Server 11.2, which implements MDEV-16329:
./mtr --rr main.alter_table_online_debug,nobinlog
|
I set a breakpoint inside ha_innobase::extra(HA_EXTRA_END_ALTER_COPY) and started to debug its surroundings:
break ha_innodb.cc:15692
|
continue
|
break ha_innobase::write_row
|
For the first statement that hits the first breakpoint (alter table t1 add b int NULL, algorithm= copy, lock= none), we can see that the row-level undo logging is being disabled as expected (MDEV-11415). But, we can also see that the initial copying phase is using the regular row-by-row-insert API if we set a data watchpoint on FIL_PAGE_LSN in the clustered index root page:
|
11.2 96250c82691169921a38a38bc24910294294eb24 |
#2 0x0000560582646449 in mtr_t::commit (this=...) at /mariadb/11/storage/innobase/mtr/mtr0mtr.cc:438
|
#3 0x00005605826a68e8 in row_ins_clust_index_entry_low (flags=..., mode=..., index=..., n_uniq=..., entry=..., n_ext=..., thr=...) at /mariadb/11/storage/innobase/row/row0ins.cc:2895
|
#4 0x00005605826a6bca in row_ins_clust_index_entry (index=..., entry=..., thr=..., n_ext=...) at /mariadb/11/storage/innobase/row/row0ins.cc:3243
|
#5 0x00005605826a6e84 in row_ins_index_entry (index=..., entry=..., thr=...) at /mariadb/11/storage/innobase/row/row0ins.cc:3375
|
#6 0x00005605826a6f50 in row_ins_index_entry_step (node=..., thr=...) at /mariadb/11/storage/innobase/row/row0ins.cc:3543
|
#7 0x00005605826a71a0 in row_ins (node=..., thr=...) at /mariadb/11/storage/innobase/row/row0ins.cc:3660
|
#8 0x00005605826a73d9 in row_ins_step (thr=...) at /mariadb/11/storage/innobase/row/row0ins.cc:3789
|
#9 0x00005605826bd2a9 in row_insert_for_mysql (mysql_rec=..., prebuilt=..., ins_mode=...) at /mariadb/11/storage/innobase/row/row0mysql.cc:1314
|
#10 0x00005605824d641b in ha_innobase::write_row (this=..., record=...) at /mariadb/11/storage/innobase/handler/ha_innodb.cc:7847
|
#11 0x0000560581ff2a35 in handler::ha_write_row (this=..., buf=...) at /mariadb/11/sql/handler.cc:7852
|
#12 0x00005605822adb11 in copy_data_between_tables (thd=..., from=..., to=..., ignore=..., order_num=..., order=..., copied=..., deleted=..., alter_info=..., alter_ctx=..., online=..., start_alter_id=...)
|
at /mariadb/11/sql/sql_table.cc:12186
|
#13 0x00005605822b0fce in mysql_alter_table (thd=..., new_db=..., new_name=..., create_info=..., table_list=..., recreate_info=..., alter_info=..., order_num=..., order=..., ignore=..., if_exists=...)
|
at /mariadb/11/sql/sql_table.cc:11335
|
#14 0x0000560582324b53 in Sql_cmd_alter_table::execute (this=..., thd=...) at /mariadb/11/sql/sql_alter.cc:701
|
#15 0x00005605821eb5c3 in mysql_execute_command (thd=..., is_called_from_prepared_stmt=...) at /mariadb/11/sql/sql_parse.cc:5777
|
#16 0x00005605821ec175 in mysql_parse (thd=..., rawbuf=..., length=..., parser_state=...) at /mariadb/11/sql/sql_parse.cc:7808
|
Because this code path provides a work-around for MDEV-26740, we had better fix that bug before we can implement this optimization.
It would be good to test the fix on 11.2 before applying it to the earliest supported version (10.11), because MDEV-16329 is extending the function copy_data_between_tables() with a call to online_alter_read_from_binlog().
Attachments
Issue Links
- is blocked by
-
MDEV-24621 In bulk insert, pre-sort and build indexes one page at a time
-
- Closed
-
-
-
- Closed
-
-
-
- Closed
-
- relates to
-
-
- Open
-
-
-
- Open
-
-
-
- Open
-