Hi OJ,
1) What do you think about using heuristic even if we don't have row-count.
E.g if we don't have row-count, set it to 100 and run you range-heuristic anyway
2) What do you think about making sure that EQ is preferred over LT even if row-count is
low,
so that the divisions don't make estimate the same...if row-count is low...
/Jonas
On 02/23/11 16:54, Ole John Aske wrote:
> #At file:///net/fimafeng09/export/home/tmp/oleja/mysql/mysql-5.1-telco-7.0/ based on
> revid:ole.john.aske@stripped
>
> 4223 Ole John Aske 2011-02-23
> Fix for bug#11804277 - INCORRECT INDEX MAY BE SELECTED DUE TO INSUFFICIENT
> STATISTICS FROM CLUSTER
>
> Add heuristics to ha_ndbcluster::records_in_range()
> which identifies a range as:
>
> - An open bound range (<column> LT/GT <bound)
> - A closed bound range (<column> BETWEEN <low> AND <HIGH>)
> - A (partial) EQ-range (<column> EQ <bound>)
>
> ... Or a combination of these....
>
> These are handled as follows:
>
> Open bound ranges
> -----------------
> Without a histogram of how the values in the index are
> distributed, we can only assume an equal distrubution.
> A statistically correct estimate for a condition of the form
> '<column> LT/GT <bound>' would then have been to assume it selects
> 50% of the rows in the table. However, I have experienced that
> this will cause the range-cost to directly compete with the cost
> of a full table scan. We should therefore be somewhat more
> conservative and estimate 10% of the rows to be returned.
>
> Closed bound range
> ------------------
> We assume this to be somewhat better than an open bounded range
> returning 5% of the rows in the table.
>
> EQ-range
> --------
> An EQ-range will excatly specify a fraction of the first part of
> an index. It is reasonable to assume:
>
> - Specifing a larger fraction of the index will improve the
> selectivity of the EQ-range.
> - Each part of the specified EQ-range will have the same
> selectivity.
>
> We can model this as a Binomial Distribution of the indexed
> values. http://en.wikipedia.org/wiki/Binomial_distrib
>
> modified:
> mysql-test/suite/ndb/r/ndb_condition_pushdown.result
> mysql-test/suite/ndb/r/ndb_index.result
> mysql-test/suite/ndb/r/ndb_index_unique.result
> mysql-test/suite/ndb/r/ndb_read_multi_range.result
> mysql-test/suite/ndb/r/ndb_statistics.result
> mysql-test/suite/ndb/t/ndb_statistics.test
> sql/ha_ndbcluster.cc
> === modified file 'mysql-test/suite/ndb/r/ndb_condition_pushdown.result'
> --- a/mysql-test/suite/ndb/r/ndb_condition_pushdown.result 2011-01-17 13:29:52 +0000
> +++ b/mysql-test/suite/ndb/r/ndb_condition_pushdown.result 2011-02-23 15:54:12 +0000
> @@ -1910,7 +1910,7 @@ insert into NodeAlias VALUES(null, 8 , '
> 12:22:26');
> explain select * from NodeAlias where (aliasKey LIKE '491803%');
> id select_type table type possible_keys key key_len ref rows Extra
> -1 SIMPLE NodeAlias range NodeAlias_KeyIndex NodeAlias_KeyIndex 48 NULL 10 Using
> where with pushed condition
> +1 SIMPLE NodeAlias range NodeAlias_KeyIndex NodeAlias_KeyIndex 48 NULL 2 Using where
> with pushed condition
> select * from NodeAlias where (aliasKey LIKE '491803%') order by id;
> id nodeId displayName aliasKey objectVersion changed
> 7 8 491803% 491803% 0 2008-03-10 12:22:26
> @@ -2225,7 +2225,7 @@ join tx as t2 on tx.a = t2.c and tx.b =
> where t2.a = 4
> group by t2.c;
> id select_type table type possible_keys key key_len ref rows filtered Extra
> -1 SIMPLE t2 ref PRIMARY PRIMARY 4 const 10 100.00 Using where; Using filesort
> +1 SIMPLE t2 ref PRIMARY PRIMARY 4 const 2 100.00 Using where; Using filesort
> 1 SIMPLE tx eq_ref PRIMARY PRIMARY 8 test.t2.c,test.t2.d 1 100.00
> Warnings:
> Note 1003 select `test`.`t2`.`c` AS `c`,count(distinct `test`.`t2`.`a`) AS
> `count(distinct t2.a)` from `test`.`tx` join `test`.`tx` `t2` where ((`test`.`tx`.`b` =
> `test`.`t2`.`d`) and (`test`.`tx`.`a` = `test`.`t2`.`c`) and (`test`.`t2`.`a` = 4)) group
> by `test`.`t2`.`c`
> @@ -2242,7 +2242,7 @@ join tx as t2 on tx.a = t2.c and tx.b =
> where t2.a = 4
> group by t2.c;
> id select_type table type possible_keys key key_len ref rows filtered Extra
> -1 SIMPLE t2 ref PRIMARY PRIMARY 4 const 10 100.00 Using where; Using filesort
> +1 SIMPLE t2 ref PRIMARY PRIMARY 4 const 2 100.00 Using where; Using filesort
> 1 SIMPLE tx eq_ref PRIMARY PRIMARY 8 test.t2.c,test.t2.d 1 100.00
> Warnings:
> Note 1003 select `test`.`t2`.`c` AS `c`,count(distinct `test`.`t2`.`a`) AS
> `count(distinct t2.a)` from `test`.`tx` join `test`.`tx` `t2` where ((`test`.`tx`.`b` =
> `test`.`t2`.`d`) and (`test`.`tx`.`a` = `test`.`t2`.`c`) and (`test`.`t2`.`a` = 4)) group
> by `test`.`t2`.`c`
>
> === modified file 'mysql-test/suite/ndb/r/ndb_index.result'
> --- a/mysql-test/suite/ndb/r/ndb_index.result 2010-12-22 11:13:45 +0000
> +++ b/mysql-test/suite/ndb/r/ndb_index.result 2011-02-23 15:54:12 +0000
> @@ -306,7 +306,7 @@ explain
> select i,vc from t1
> where i>=1 or vc > '0';
> id select_type table type possible_keys key key_len ref rows Extra
> -1 SIMPLE t1 index_merge PRIMARY,i1,i2 i1,i2 5,18 NULL 20 Using sort_union(i1,i2);
> Using where with pushed condition
> +1 SIMPLE t1 index_merge PRIMARY,i1,i2 i1,i2 5,18 NULL 4 Using sort_union(i1,i2);
> Using where with pushed condition
> select i,vc from t1
> where i>=1 or vc > '0';
> i vc
> @@ -350,7 +350,7 @@ explain
> select i,vc from t2
> where i>=1 or vc > '0';
> id select_type table type possible_keys key key_len ref rows Extra
> -1 SIMPLE t2 index_merge i1,i2 i1,i2 5,19 NULL 20 Using sort_union(i1,i2); Using
> where with pushed condition
> +1 SIMPLE t2 index_merge i1,i2 i1,i2 5,19 NULL 4 Using sort_union(i1,i2); Using where
> with pushed condition
> select i,vc from t2
> where i>=1 or vc > '0';
> i vc
>
> === modified file 'mysql-test/suite/ndb/r/ndb_index_unique.result'
> --- a/mysql-test/suite/ndb/r/ndb_index_unique.result 2011-01-18 07:49:14 +0000
> +++ b/mysql-test/suite/ndb/r/ndb_index_unique.result 2011-02-23 15:54:12 +0000
> @@ -185,7 +185,7 @@ set @old_ecpd = @@session.engine_conditi
> set engine_condition_pushdown = true;
> explain select * from t2 where (b = 3 OR b = 5) AND c IS NULL AND a < 9 order by
> a;
> id select_type table type possible_keys key key_len ref rows Extra
> -1 SIMPLE t2 range PRIMARY,b b 9 NULL 2 Using where with pushed condition; Using
> filesort
> +1 SIMPLE t2 range PRIMARY,b PRIMARY 4 NULL 2 Using where with pushed condition
> select * from t2 where (b = 3 OR b = 5) AND c IS NULL AND a < 9 order by a;
> a b c
> 3 3 NULL
>
> === modified file 'mysql-test/suite/ndb/r/ndb_read_multi_range.result'
> --- a/mysql-test/suite/ndb/r/ndb_read_multi_range.result 2011-01-18 07:49:14 +0000
> +++ b/mysql-test/suite/ndb/r/ndb_read_multi_range.result 2011-02-23 15:54:12 +0000
> @@ -605,7 +605,7 @@ SELECT DISTINCT STRAIGHT_JOIN t1.pk FROM
> t1 LEFT JOIN t2 ON t2.a = t1.a AND t2.pk != 6;
> id select_type table type possible_keys key key_len ref rows Extra
> 1 SIMPLE t1 ALL NULL NULL NULL NULL 3000 Using temporary
> -1 SIMPLE t2 range PRIMARY PRIMARY 4 NULL 20 Using where; Distinct
> +1 SIMPLE t2 range PRIMARY PRIMARY 4 NULL 4 Using where; Distinct
> SELECT DISTINCT STRAIGHT_JOIN t1.pk FROM
> t1 LEFT JOIN t2 ON t2.a = t1.a AND t2.pk != 6;
> drop table t1, t2;
>
> === modified file 'mysql-test/suite/ndb/r/ndb_statistics.result'
> --- a/mysql-test/suite/ndb/r/ndb_statistics.result 2011-01-18 11:49:03 +0000
> +++ b/mysql-test/suite/ndb/r/ndb_statistics.result 2011-02-23 15:54:12 +0000
> @@ -38,24 +38,124 @@ id select_type table type possible_keys
> EXPLAIN
> SELECT * FROM t10000 WHERE k >= 42 and k < 10000;
> id select_type table type possible_keys key key_len ref rows Extra
> -1 SIMPLE t10000 range PRIMARY PRIMARY 4 NULL 10 Using where with pushed condition
> +1 SIMPLE t10000 range PRIMARY PRIMARY 4 NULL 500 Using where with pushed condition
> EXPLAIN
> SELECT * FROM t10000 WHERE k BETWEEN 42 AND 10000;
> id select_type table type possible_keys key key_len ref rows Extra
> -1 SIMPLE t10000 range PRIMARY PRIMARY 4 NULL 10 Using where with pushed condition
> +1 SIMPLE t10000 range PRIMARY PRIMARY 4 NULL 500 Using where with pushed condition
> EXPLAIN
> SELECT * FROM t10000 WHERE k < 42;
> id select_type table type possible_keys key key_len ref rows Extra
> -1 SIMPLE t10000 range PRIMARY PRIMARY 4 NULL 10 Using where with pushed condition
> +1 SIMPLE t10000 range PRIMARY PRIMARY 4 NULL 1000 Using where with pushed condition
> EXPLAIN
> SELECT * FROM t10000 WHERE k > 42;
> id select_type table type possible_keys key key_len ref rows Extra
> -1 SIMPLE t10000 range PRIMARY PRIMARY 4 NULL 10 Using where with pushed condition
> +1 SIMPLE t10000 range PRIMARY PRIMARY 4 NULL 1000 Using where with pushed condition
> EXPLAIN
> SELECT * FROM t10000 AS X JOIN t10000 AS Y
> ON Y.I=X.I AND Y.J = X.I;
> id select_type table type possible_keys key key_len ref rows Extra
> 1 SIMPLE X ALL I NULL NULL NULL 10000
> 1 SIMPLE Y ref J,I I 10 test.X.I,test.X.I 11 Using where
> +EXPLAIN
> +SELECT * FROM t100 WHERE k < 42;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t100 range PRIMARY PRIMARY 4 NULL 10 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t100 WHERE k > 42;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t100 range PRIMARY PRIMARY 4 NULL 10 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE k < 42;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 range PRIMARY PRIMARY 4 NULL 1000 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE k > 42;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 range PRIMARY PRIMARY 4 NULL 1000 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t100 WHERE k BETWEEN 42 AND 10000;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t100 range PRIMARY PRIMARY 4 NULL 5 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE k BETWEEN 42 AND 10000;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 range PRIMARY PRIMARY 4 NULL 500 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I = 0;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 ref I I 5 const 200 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J = 0;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 ref J J 5 const 100 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I = 0 AND J = 0;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 ref J,I I 10 const,const 4 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I = 0;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 ref I I 5 const 200 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I = 0 AND J > 1;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 range J,I I 10 NULL 100 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I = 0 AND J < 1;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 range J,I I 10 NULL 50 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I = 0 AND J BETWEEN 1 AND 10;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 range J,I I 10 NULL 50 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I = 0 AND J = 1;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 ref J,I I 10 const,const 4 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J = 0;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 ref J J 5 const 100 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J = 0 AND K > 1;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 range PRIMARY,J J 9 NULL 50 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J = 0 AND K < 1;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 range PRIMARY,J J 9 NULL 50 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J = 0 AND K BETWEEN 1 AND 10;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 range PRIMARY,J J 9 NULL 25 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J = 0 AND K = 1;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading
> const tables
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I = 0 AND J > 1;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 range J,I I 10 NULL 100 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I > 0 AND J = 1;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 ref J,I J 5 const 100 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I > 0 AND J > 1;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 range J,I J 5 NULL 1000 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J > 1 AND I = 0;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 range J,I I 10 NULL 100 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J = 1 AND I > 0;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 ref J,I J 5 const 100 Using where with pushed condition
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J > 1 AND I > 0;
> +id select_type table type possible_keys key key_len ref rows Extra
> +1 SIMPLE t10000 range J,I J 5 NULL 1000 Using where with pushed condition
> DROP TABLE t10,t100,t10000;
> End of 5.1 tests
>
> === modified file 'mysql-test/suite/ndb/t/ndb_statistics.test'
> --- a/mysql-test/suite/ndb/t/ndb_statistics.test 2011-01-18 11:49:03 +0000
> +++ b/mysql-test/suite/ndb/t/ndb_statistics.test 2011-02-23 15:54:12 +0000
> @@ -62,6 +62,81 @@ EXPLAIN
> SELECT * FROM t10000 AS X JOIN t10000 AS Y
> ON Y.I=X.I AND Y.J = X.I;
>
> +#
> +# Improved heurists for ::records_in_range() statistics
> +#
> +
> +# Open bounded range should return 10% of #rows in table
> +EXPLAIN
> +SELECT * FROM t100 WHERE k < 42;
> +EXPLAIN
> +SELECT * FROM t100 WHERE k > 42;
> +EXPLAIN
> +SELECT * FROM t10000 WHERE k < 42;
> +EXPLAIN
> +SELECT * FROM t10000 WHERE k > 42;
> +
> +#Closed bounded range should return 5% of #rows in table
> +EXPLAIN
> +SELECT * FROM t100 WHERE k BETWEEN 42 AND 10000;
> +EXPLAIN
> +SELECT * FROM t10000 WHERE k BETWEEN 42 AND 10000;
> +
> +#EQ-range selectivity depends on
> +# - key length specified
> +# - #rows in table.
> +# - unique/non-unique index
> +# - min 2% selectivity
> +#
> +# Possibly combined with open/closed ranges as
> +# above which further improves selectivity
> +#
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I = 0;
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J = 0;
> +
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I = 0 AND J = 0;
> +
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I = 0;
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I = 0 AND J > 1;
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I = 0 AND J < 1;
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I = 0 AND J BETWEEN 1 AND 10;
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I = 0 AND J = 1;
> +
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J = 0;
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J = 0 AND K > 1;
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J = 0 AND K < 1;
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J = 0 AND K BETWEEN 1 AND 10;
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J = 0 AND K = 1;
> +
> +## Verify selection of 'best' index
> +## (The one of index I/J being EQ)
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I = 0 AND J <> 1;
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I <> 0 AND J = 1;
> +EXPLAIN
> +SELECT * FROM t10000 WHERE I <> 0 AND J <> 1;
> +
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J <> 1 AND I = 0;
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J = 1 AND I <> 0;
> +EXPLAIN
> +SELECT * FROM t10000 WHERE J <> 1 AND I <> 0;
> +
>
> DROP TABLE t10,t100,t10000;
>
>
> === modified file 'sql/ha_ndbcluster.cc'
> --- a/sql/ha_ndbcluster.cc 2011-02-18 10:19:20 +0000
> +++ b/sql/ha_ndbcluster.cc 2011-02-23 15:54:12 +0000
> @@ -11182,7 +11182,87 @@ ha_ndbcluster::records_in_range(uint inx
> DBUG_RETURN(rows);
> }
>
> - DBUG_RETURN(10); /* Good guess when you don't know anything */
> + /* Use simple heuristics to estimate fraction
> + of 'stats.record' returned from range.
> + */
> + if (stats.records != 0 && stats.records != HA_POS_ERROR)
> + {
> + Uint64 rows;
> + Uint64 table_rows= stats.records;
> + size_t min_key_length= (min_key) ? min_key->length : 0;
> + size_t max_key_length= (max_key) ? max_key->length : 0;
> +
> + // Might have an closed/open range bound:
> + // Low range open
> + if (!min_key_length)
> + {
> + rows= (!max_key_length)
> + ? table_rows // No range was specified
> + : table_rows/10; // -oo .. <high range> -> 10%
> selectivity
> + }
> + // High range open
> + else if (!max_key_length)
> + {
> + rows= table_rows/10; // <low range>..oo -> 10%
> selectivity
> + }
> + else
> + {
> + size_t bounds_len= min(min_key_length,max_key_length);
> + uint eq_bound_len= 0;
> + uint eq_bound_offs= 0;
> +
> + KEY_PART_INFO* key_part= key_info->key_part;
> + KEY_PART_INFO* end= key_part+key_info->key_parts;
> + for (; key_part != end; key_part++)
> + {
> + uint part_length= key_part->store_length;
> + if (eq_bound_offs+part_length > bounds_len ||
> + memcmp(&min_key->key[eq_bound_offs],
> + &max_key->key[eq_bound_offs],
> + part_length))
> + {
> + break;
> + }
> + eq_bound_len+= key_part->length;
> + eq_bound_offs+= part_length;
> + }
> +
> + if (!eq_bound_len)
> + {
> + rows= table_rows/20; // <low range>..<high range>
> -> 5% selectivity
> + }
> + else
> + {
> + // Has an equality range on a leading part of 'key_length':
> + // - Null indicator, and HA_KEY_BLOB_LENGTH bytes in
> + // 'extra_length' are removed from key_fraction calculations.
> + // - Assume reduced selectivity for non-unique indexes
> + // by decreasing 'eq_fraction' by 20%
> + // - Assume equal selectivity for all eq_parts in key.
> +
> + double eq_fraction = (double)(eq_bound_len) /
> + (key_length - key_info->extra_length);
> + if (idx_type == ORDERED_INDEX) // Non-unique index -> less selectivity
> + eq_fraction/= 1.20;
> + if (eq_fraction >= 1.0) // Exact match -> 1 row
> + DBUG_RETURN(1);
> +
> + rows = (Uint64)(table_rows / pow(table_rows, eq_fraction));
> + if (rows > (table_rows/50)) // EQ-range: Max 2% of rows
> + rows= (table_rows/50);
> +
> + if (min_key_length > eq_bound_offs)
> + rows/= 2;
> + if (max_key_length > eq_bound_offs)
> + rows/= 2;
> + }
> + }
> + if (rows < 2) // At least 2 rows as not exact
> + rows= 2;
> + DBUG_RETURN(min(rows,table_rows));
> + }
> +
> + DBUG_RETURN(10); /* Poor guess when you don't know anything */
> }
>
> ulonglong ha_ndbcluster::table_flags(void) const
>
>
>
>
>
