database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-29 05:21:33 +03:00
Code Activity

MDEV-25654 Unexpected ER_CRASHED_ON_USAGE and Assertion

Browse Source 
`limit >= trx_id' failed in purge_node_t::skip

For fast alter partition ALTER lost hash fields in frm field
count. mysql_prepare_create_table() did not call add_hash_field()
because the logic of ALTER-ing field types implies automatic
promotion/demotion to/from hash index. So we don't pass hash algorithm
to mysql_prepare_create_table() and let it decide itself, but it
cannot decide it correctly for fast alter partition.

So now mysql_prepare_alter_table() is a bit more sophisticated on what
to pass in the algorithm. If not changed any fields it will force
mysql_prepare_create_table() to re-add hash fields by setting
HA_KEY_ALG_HASH.

The problem with the original logic is mysql_prepare_alter_table()
does not care 100% about hash property so the decision is blurred
between mysql_prepare_alter_table() and mysql_prepare_create_table().
This commit is contained in:
Aleksey Midenkov
2025-01-13 15:40:58 +03:00
parent 0cf2176b79
commit 0dcd30197a
3 changed files with 41 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
sql/sql_table.cc
View File

@ -9264,7 +9264,20 @@ mysql_prepare_alter_table(THD *thd, TABLE *table,
LEX_CSTRING tmp_name;
bzero((char*) &key_create_info, sizeof(key_create_info));
if (key_info->algorithm == HA_KEY_ALG_LONG_HASH)
key_info->algorithm= HA_KEY_ALG_UNDEF;
key_info->algorithm= (alter_info->flags & ALTER_CHANGE_COLUMN) ?
HA_KEY_ALG_UNDEF : HA_KEY_ALG_HASH;
/*
This one goes to mysql_prepare_create_table():
key_info->algorithm= key->key_create_info.algorithm;
For HA_KEY_ALG_LONG_HASH if we didn't change ANY column, we pass
HA_KEY_ALG_HASH to ensure mysql_prepare_create_table() does add_hash_field().
This protects fast alter partition from losing hash properties.
In case of any column changes we drop algorithm to HA_KEY_ALG_UNDEF and
let decide mysql_prepare_create_table() if the hash field is needed
depending on new types.
*/
key_create_info.algorithm= key_info->algorithm;
/*
We copy block size directly as some engines, like Area, sets this