Commit 2310ef69 authored by heikki@hundin.mysql.fi's avatar heikki@hundin.mysql.fi

Merge hundin.mysql.fi:/home/heikki/mysql-4.0

into  hundin.mysql.fi:/home/heikki/mysql-4.1
parents 4d2cc6e5 9f72d504
......@@ -4443,6 +4443,7 @@ ha_innobase::info(
dict_table_t* ib_table;
dict_index_t* index;
ha_rows rec_per_key;
ib_longlong n_rows;
ulong j;
ulong i;
char path[FN_REFLEN];
......@@ -4507,7 +4508,30 @@ ha_innobase::info(
}
if (flag & HA_STATUS_VARIABLE) {
records = (ha_rows)ib_table->stat_n_rows;
n_rows = ib_table->stat_n_rows;
/* Because we do not protect stat_n_rows by any mutex in a
delete, it is theoretically possible that the value can be
smaller than zero! TODO: fix this race.
The MySQL optimizer seems to assume in a left join that n_rows
is an accurate estimate if it is zero. Of course, it is not,
since we do not have any locks on the rows yet at this phase.
Since SHOW TABLE STATUS seems to call this function with the
HA_STATUS_TIME flag set, while the left join optizer does not
set that flag, we add one to a zero value if the flag is not
set. That way SHOW TABLE STATUS will show the best estimate,
while the optimizer never sees the table empty. */
if (n_rows < 0) {
n_rows = 0;
}
if (n_rows == 0 && !(flag & HA_STATUS_TIME)) {
n_rows++;
}
records = (ha_rows)n_rows;
deleted = 0;
data_file_length = ((ulonglong)
ib_table->stat_clustered_index_size)
......
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