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BUG#20725 MySQLD cluster use "fast count" is broken

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Post recent handler changes, fast count(*) for cluster was broken.

Seeing as we maintain an exact count for ndb, we can easily use this for an optimisation.

With this patch, and use_exact_count DISABLED, we will use the fast way
of getting count(*) but not use the exact count for the optimiser.

With this patch and use_exact_count ENABLED, we will use the fast way of
getting count(*) and use the exact count for the optimiser.


sql/ha_ndbcluster.cc:
  Implement handler::records() and set appropriate handler flag.
sql/ha_ndbcluster.h:
  we implment handler::records() for fast count(*)
This commit is contained in:
unknown 2006-06-28 01:07:44 +10:00
commit 9512629598
2 changed files with 27 additions and 1 deletions
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27
sql/ha_ndbcluster.cc
View file

@ -414,6 +414,30 @@ void ha_ndbcluster::set_rec_per_key()
DBUG_VOID_RETURN;
}
ha_rows ha_ndbcluster::records()
{
ha_rows retval;
DBUG_ENTER("ha_ndbcluster::records");
struct Ndb_local_table_statistics *info= m_table_info;
DBUG_PRINT("info", ("id=%d, no_uncommitted_rows_count=%d",
((const NDBTAB *)m_table)->getTableId(),
info->no_uncommitted_rows_count));
Ndb *ndb= get_ndb();
ndb->setDatabaseName(m_dbname);
struct Ndb_statistics stat;
if (ndb_get_table_statistics(ndb, m_table, &stat) == 0)
{
retval= stat.row_count;
}
THD *thd= current_thd;
if (get_thd_ndb(thd)->error)
info->no_uncommitted_rows_count= 0;
DBUG_RETURN(retval + info->no_uncommitted_rows_count);
}
void ha_ndbcluster::records_update()
{
if (m_ha_not_exact_count)
@ -5455,7 +5479,8 @@ void ha_ndbcluster::get_auto_increment(ulonglong offset, ulonglong increment,
HA_PRIMARY_KEY_REQUIRED_FOR_POSITION | \
HA_PRIMARY_KEY_REQUIRED_FOR_DELETE | \
HA_PARTIAL_COLUMN_READ | \
HA_HAS_OWN_BINLOGGING
HA_HAS_OWN_BINLOGGING | \
HA_HAS_RECORDS
ha_ndbcluster::ha_ndbcluster(TABLE_SHARE *table_arg):
handler(&ndbcluster_hton, table_arg),

1
sql/ha_ndbcluster.h
View file

@ -622,6 +622,7 @@ class ha_ndbcluster: public handler
int read_multi_range_next(KEY_MULTI_RANGE **found_range_p);
bool get_error_message(int error, String *buf);
ha_rows records();
void info(uint);
void get_dynamic_partition_info(PARTITION_INFO *stat_info, uint part_id);
int extra(enum ha_extra_function operation);