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Faster alter table code for 5.1.

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This commit is contained in:
jani@a193-229-222-105.elisa-laajakaista.fi
2005-07-22 23:43:59 +03:00
parent 5eab6ddcd6
commit 2657e48c64
25 changed files with 480 additions and 26 deletions
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230
sql/sql_table.cc
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@ -1348,6 +1348,34 @@ static int mysql_prepare_table(THD *thd, HA_CREATE_INFO *create_info,
}
/*
Set table default charset, if not set
SYNOPSIS
set_table_default_charset()
create_info Table create information
DESCRIPTION
If the table character set was not given explicitely,
let's fetch the database default character set and
apply it to the table.
*/
static void set_table_default_charset(THD *thd,
HA_CREATE_INFO *create_info, char *db)
{
if (!create_info->default_table_charset)
{
HA_CREATE_INFO db_info;
char path[FN_REFLEN];
/* Abuse build_table_path() to build the path to the db.opt file */
build_table_path(path, sizeof(path), db, MY_DB_OPT_FILE, "");
load_db_opt(thd, path, &db_info);
create_info->default_table_charset= db_info.default_table_charset;
}
}
/*
Extend long VARCHAR fields to blob & prepare field if it's a blob
@ -1532,20 +1560,7 @@ bool mysql_create_table(THD *thd,const char *db, const char *table_name,
}
#endif
/*
If the table character set was not given explicitely,
let's fetch the database default character set and
apply it to the table.
*/
if (!create_info->default_table_charset)
{
HA_CREATE_INFO db_info;
char path[FN_REFLEN];
/* Abuse build_table_path() to build the path to the db.opt file */
build_table_path(path, sizeof(path), db, MY_DB_OPT_FILE, "");
load_db_opt(thd, path, &db_info);
create_info->default_table_charset= db_info.default_table_charset;
}
set_table_default_charset(thd, create_info, (char*) db);
if (mysql_prepare_table(thd, create_info, &fields,
&keys, internal_tmp_table, &db_options, file,
@ -3029,6 +3044,166 @@ int mysql_drop_indexes(THD *thd, TABLE_LIST *table_list,
#endif /* NOT_USED */
#define ALTER_TABLE_DATA_CHANGED 1
#define ALTER_TABLE_INDEX_CHANGED 2
/*
SYNOPSIS
compare tables()
table original table
create_list fields in new table
key_list keys in new table
create_info create options in new table
DESCRIPTION
'table' (first argument) contains information of the original
table, which includes all corresponding parts that the new
table has in arguments create_list, key_list and create_info.
By comparing the changes between the original and new table
we can determine how much it has changed after ALTER TABLE
and whether we need to make a copy of the table, or just change
the .frm file.
RETURN VALUES
0 No copy needed
1 Data changes, copy needed
2 Index changes, copy needed
*/
uint compare_tables(TABLE *table, List<create_field> *create_list,
List<Key> *key_list, HA_CREATE_INFO *create_info,
ALTER_INFO *alter_info, uint order_num)
{
Field **f_ptr, *field;
uint changes= 0, tmp;
List_iterator_fast<create_field> new_field_it(*create_list);
create_field *new_field;
/*
Some very basic checks. If number of fields changes, or the
handler, we need to run full ALTER TABLE. In the future
new fields can be added and old dropped without copy, but
not yet.
Test also that engine was not given during ALTER TABLE, or
we are force to run regular alter table (copy).
E.g. ALTER TABLE tbl_name ENGINE=MyISAM.
For the following ones we also want to run regular alter table:
ALTER TABLE tbl_name ORDER BY ..
ALTER TABLE tbl_name CONVERT TO CHARACTER SET ..
At the moment we can't handle altering temporary tables without a copy.
We also test if OPTIMIZE TABLE was given and was mapped to alter table.
In that case we always do full copy.
*/
if (table->s->fields != create_list->elements ||
table->s->db_type != create_info->db_type ||
table->s->tmp_table ||
create_info->used_fields & HA_CREATE_USED_ENGINE ||
create_info->used_fields & HA_CREATE_USED_CHARSET ||
create_info->used_fields & HA_CREATE_USED_DEFAULT_CHARSET ||
(alter_info->flags & ALTER_RECREATE) ||
order_num)
return ALTER_TABLE_DATA_CHANGED;
/*
Go through fields and check if the original ones are compatible
with new table.
*/
for (f_ptr= table->field, new_field= new_field_it++;
(field= *f_ptr); f_ptr++, new_field= new_field_it++)
{
/* Make sure we have at least the default charset in use. */
if (!new_field->charset)
new_field->charset= create_info->default_table_charset;
/* Check that NULL behavior is same for old and new fields */
if ((new_field->flags & NOT_NULL_FLAG) !=
(uint) (field->flags & NOT_NULL_FLAG))
return ALTER_TABLE_DATA_CHANGED;
/* Don't pack rows in old tables if the user has requested this. */
if (create_info->row_type == ROW_TYPE_DYNAMIC ||
(new_field->flags & BLOB_FLAG) ||
new_field->sql_type == MYSQL_TYPE_VARCHAR &&
create_info->row_type != ROW_TYPE_FIXED)
create_info->table_options|= HA_OPTION_PACK_RECORD;
/* Evaluate changes bitmap and send to check_if_incompatible_data() */
if (!(tmp= field->is_equal(new_field)))
return ALTER_TABLE_DATA_CHANGED;
changes|= tmp;
}
/* Check if changes are compatible with current handler without a copy */
if (table->file->check_if_incompatible_data(create_info, changes))
return ALTER_TABLE_DATA_CHANGED;
/*
Go through keys and check if the original ones are compatible
with new table.
*/
KEY *table_key_info= table->key_info;
List_iterator_fast<Key> key_it(*key_list);
Key *key= key_it++;
/* Check if the number of key elements has changed */
if (table->s->keys != key_list->elements)
return ALTER_TABLE_INDEX_CHANGED;
for (uint i= 0; i < table->s->keys; i++, table_key_info++, key= key_it++)
{
/*
Check that the key types are compatible between old and new tables.
*/
if (table_key_info->algorithm != key->algorithm ||
((key->type == Key::PRIMARY || key->type == Key::UNIQUE) &&
!(table_key_info->flags & HA_NOSAME)) ||
(!(key->type == Key::PRIMARY || key->type == Key::UNIQUE) &&
(table_key_info->flags & HA_NOSAME)) ||
((key->type == Key::SPATIAL) &&
!(table_key_info->flags & HA_SPATIAL)) ||
(!(key->type == Key::SPATIAL) &&
(table_key_info->flags & HA_SPATIAL)) ||
((key->type == Key::FULLTEXT) &&
!(table_key_info->flags & HA_FULLTEXT)) ||
(!(key->type == Key::FULLTEXT) &&
(table_key_info->flags & HA_FULLTEXT)))
return ALTER_TABLE_INDEX_CHANGED;
if (table_key_info->key_parts != key->columns.elements)
return ALTER_TABLE_INDEX_CHANGED;
/*
Check that the key parts remain compatible between the old and
new tables.
*/
KEY_PART_INFO *table_key_part= table_key_info->key_part;
List_iterator_fast<key_part_spec> key_part_it(key->columns);
key_part_spec *key_part= key_part_it++;
for (uint j= 0; j < table_key_info->key_parts; j++,
table_key_part++, key_part= key_part_it++)
{
/*
Key definition has changed if we are using a different field or
if the used key length is different
(If key_part->length == 0 it means we are using the whole field)
*/
if (strcmp(key_part->field_name, table_key_part->field->field_name) ||
(key_part->length && key_part->length != table_key_part->length) ||
(key_part->length == 0 && table_key_part->length !=
table_key_part->field->pack_length()))
return ALTER_TABLE_INDEX_CHANGED;
}
}
return 0; // Tables are compatible
}
/*
Alter table
*/
@ -3050,7 +3225,7 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
ulonglong next_insert_id;
uint db_create_options, used_fields;
enum db_type old_db_type,new_db_type;
bool need_copy_table;
uint need_copy_table= 0;
DBUG_ENTER("mysql_alter_table");
thd->proc_info="init";
@ -3282,8 +3457,8 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
def_it.remove();
}
}
else
{ // Use old field value
else // This field was not dropped and not changed, add it to the list
{ // for the new table.
create_list.push_back(def=new create_field(field,field));
alter_it.rewind(); // Change default if ALTER
Alter_column *alter;
@ -3495,17 +3670,22 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
if (table->s->tmp_table)
create_info->options|=HA_LEX_CREATE_TMP_TABLE;
set_table_default_charset(thd, create_info, db);
if (thd->variables.old_alter_table)
need_copy_table= 1;
else
need_copy_table= compare_tables(table, &create_list, &key_list,
create_info, alter_info, order_num);
/*
better have a negative test here, instead of positive, like
alter_info->flags & ALTER_ADD_COLUMN|ALTER_ADD_INDEX|...
so that ALTER TABLE won't break when somebody will add new flag
*/
need_copy_table= (alter_info->flags &
~(ALTER_CHANGE_COLUMN_DEFAULT|ALTER_OPTIONS) ||
(create_info->used_fields &
~(HA_CREATE_USED_COMMENT|HA_CREATE_USED_PASSWORD)) ||
table->s->tmp_table);
create_info->frm_only= !need_copy_table;
if (!need_copy_table)
create_info->frm_only= 1;
/*
Handling of symlinked tables:
@ -3811,7 +3991,7 @@ end_temporary:
err:
DBUG_RETURN(TRUE);
}
/* mysql_alter_table */
static int
copy_data_between_tables(TABLE *from,TABLE *to,
@ -4023,7 +4203,7 @@ bool mysql_recreate_table(THD *thd, TABLE_LIST *table_list,
create_info.row_type=ROW_TYPE_NOT_USED;
create_info.default_table_charset=default_charset_info;
/* Force alter table to recreate table */
lex->alter_info.flags= ALTER_CHANGE_COLUMN;
lex->alter_info.flags= (ALTER_CHANGE_COLUMN | ALTER_RECREATE);
DBUG_RETURN(mysql_alter_table(thd, NullS, NullS, &create_info,
table_list, lex->create_list,
lex->key_list, 0, (ORDER *) 0,