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MDEV-22491 Support mariadb-check and CHECK TABLE with SEQUENCE

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The check go through the following steps:

1. Run check on the underlying engine. If not ok, then return.
2. Check that there's only one row in the table, and
   2.1 warn if more than one row
   2.2 return HA_ADMIN_CORRUPT if fewer than one row (i.e. 0 rows)
3. If the sequence is not initialised (e.g. after an ALTER TABLE ...
   SEQUENCE=1), initialise the sequence by reading the sequence
   metadata from the table. This will also flush the next_free_value,
   i.e. set it to the next not cached value (SEQUENCE::reserved_until)
4. Check that the sequence metadata is valid, i.e. nothing out of
   order e.g. minvalue < maxvalue etc. If invalid it reports
   HA_ERR_SEQUENCE_INVALID_DATA
5. Check that the sequence has not been exhausted. It reports
   ER_SEQUENCE_RUN_OUT as a warning if and only if a SELECT NEXTVAL
   would do so

Limitations:

1. The check is independent of flags, so the vanilla check is the same
   as CHECK ... EXTENDED or CHECK ... FOR UPGRADE etc.
2. When the check discovers invalid metadata from the table,
   subsequent SELECT NEXTVAL will carry on (or fail) without this
   piece of knowledge, independent of the CHECK. This is to ensure
   consistency, i.e. CHECK does not modify behaviour of SELECT, and if
   anything it makes more sense that SELECT reports
   HA_ERR_SEQUENCE_INVALID_DATA in this case, regardless of prior
   CHECK
This commit is contained in:
Yuchen Pei
2025-05-02 10:44:45 +10:00
parent 26ea37be5d
commit d52ddae57b
10 changed files with 333 additions and 12 deletions
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10
sql/sql_sequence.h
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@ -95,7 +95,8 @@ public:
longlong value_type_max();
/* min value for the value type, e.g. -32768 for smallint. */
longlong value_type_min();
bool check_and_adjust(THD *thd, bool set_reserved_until);
bool check_and_adjust(THD *thd, bool set_reserved_until,
bool adjust_next= true);
void store_fields(TABLE *table);
void read_fields(TABLE *table);
int write_initial_sequence(TABLE *table);
@ -153,6 +154,13 @@ public:
longlong next_value(TABLE *table, bool second_round, int *error);
int set_value(TABLE *table, longlong next_value, ulonglong round_arg,
bool is_used);
bool has_run_out()
{
return all_values_used ||
(!cycle &&
!within_bound(next_free_value, max_value + 1, min_value - 1,
real_increment > 0));
}
bool all_values_used;
seq_init initialized;