/*
* desc_disk_to_attr_info - convert RECDES for specified oid to
* HEAP_CACHE_ATTRINFO structure
* return: error status
* oid(in): the oid of the object
* recdes(in): RECDES structure to convert
* attr_info(out): the HEAP_CACHE_ATTRINFO structure
*/
static int
desc_disk_to_attr_info (THREAD_ENTRY * thread_p, OID * oid, RECDES * recdes,
HEAP_CACHE_ATTRINFO * attr_info)
{
if (oid == NULL || recdes == NULL || attr_info == NULL)
{
return ER_FAILED;
}
if (heap_attrinfo_clear_dbvalues (attr_info) != NO_ERROR)
{
return ER_FAILED;
}
if (heap_attrinfo_read_dbvalues (thread_p, oid, recdes, attr_info) !=
NO_ERROR)
{
return ER_FAILED;
}
return NO_ERROR;
}
/*
* xstats_update_class_statistics () - Updates the statistics for the objects
* of a given class
* return:
* class_id(in): Identifier of the class
*
* Note: It first retrieves the whole catalog information about this class,
* including all possible forms of disk representations for the instance
* objects. Then, it performs a complete pass on the heap file of the
* class, reading in all of the instance objects one by one and
* calculating the ranges of numeric attribute values (ie. min. & max.
* values for each numeric attribute).
*
* During this pass on the heap file, these values are maintained
* separately for objects with the same representation. Each minimum and
* maximum value is initialized when the first instance of the class
* with the corresponding representation is encountered. These values are
* continually updated as attribute values exceeding the known range are
* encountered. At the end of this pass, these individual ranges for
* each representation are uniformed in the last (the current)
* representation, building the global range values for the attributes
* of the class. Then, the btree statistical information is obtained for
* each attribute that is indexed and stored in this final representation
* structure. Finally, a new timestamp is obtained for these class
* statistics and they are stored to disk within the catalog structure
* for the last class representation.
*/
int
xstats_update_class_statistics (THREAD_ENTRY * thread_p, OID * class_id_p)
{
CLS_INFO *cls_info_p = NULL;
REPR_ID repr_id;
DISK_REPR *disk_repr_p = NULL;
DISK_ATTR *disk_attr_p = NULL;
BTREE_STATS *btree_stats_p = NULL;
HEAP_SCANCACHE hf_scan_cache, *hf_scan_cache_p = NULL;
HEAP_CACHE_ATTRINFO hf_cache_attr_info, *hf_cache_attr_info_p = NULL;
RECDES recdes;
OID oid;
SCAN_CODE scan_rc;
DB_VALUE *db_value_p;
DB_DATA *db_data_p;
int i, j;
cls_info_p = catalog_get_class_info (thread_p, class_id_p);
if (cls_info_p == NULL)
{
goto error;
}
/* if class information was not obtained */
if (cls_info_p->hfid.vfid.fileid < 0 || cls_info_p->hfid.vfid.volid < 0)
{
/* The class does not have a heap file (i.e. it has no instances);
so no statistics can be obtained for this class; just set
'tot_objects' field to 0 and return. */
cls_info_p->tot_objects = 0;
if (catalog_add_class_info (thread_p, class_id_p, cls_info_p) !=
NO_ERROR)
{
goto error;
}
catalog_free_class_info (cls_info_p);
return NO_ERROR;
}
if (catalog_get_last_representation_id (thread_p, class_id_p, &repr_id) !=
NO_ERROR)
{
goto error;
}
disk_repr_p = catalog_get_representation (thread_p, class_id_p, repr_id);
if (disk_repr_p == NULL)
{
goto error;
}
cls_info_p->tot_pages = file_get_numpages (thread_p,
&cls_info_p->hfid.vfid);
cls_info_p->tot_objects = 0;
disk_repr_p->num_objects = 0;
/* scan whole object of the class and update the statistics */
if (heap_scancache_start (thread_p, &hf_scan_cache, &(cls_info_p->hfid),
class_id_p, true, false,
LOCKHINT_NONE) != NO_ERROR)
{
goto error;
}
hf_scan_cache_p = &hf_scan_cache;
if (heap_attrinfo_start (thread_p, class_id_p, -1, NULL,
&hf_cache_attr_info) != NO_ERROR)
{
goto error;
}
hf_cache_attr_info_p = &hf_cache_attr_info;
/* Obtain minimum and maximum value of the instances for each attribute of
the class and count the number of objects by scanning heap file */
recdes.area_size = -1;
scan_rc = heap_first (thread_p, &(cls_info_p->hfid), class_id_p, &oid,
&recdes, hf_scan_cache_p, PEEK);
while (scan_rc == S_SUCCESS)
{
if (heap_attrinfo_read_dbvalues (thread_p, &oid, &recdes,
hf_cache_attr_info_p) != NO_ERROR)
{
scan_rc = S_ERROR;
break;
}
/* Consider attributes only whose type are fixed because min/max value
statistics are useful only for those type when calculating the cost
of query plan by query optimizer. Variable type attributes, for
example VARCHAR(STRING), take constant number of selectivity. */
for (i = 0; i < disk_repr_p->n_fixed; i++)
{
disk_attr_p = &(disk_repr_p->fixed[i]);
db_value_p = heap_attrinfo_access (disk_attr_p->id,
hf_cache_attr_info_p);
if (db_value_p != NULL && db_value_is_null (db_value_p) != true)
{
db_data_p = db_value_get_db_data (db_value_p);
if (disk_repr_p->num_objects == 0)
{
/* first object */
disk_attr_p->min_value = *db_data_p;
disk_attr_p->max_value = *db_data_p;
}
else
{
/* compare with previous values */
if (stats_compare_data (db_data_p, &disk_attr_p->min_value,
disk_attr_p->type) < 0)
{
disk_attr_p->min_value = *db_data_p;
}
if (stats_compare_data (db_data_p, &disk_attr_p->max_value,
disk_attr_p->type) > 0)
{
disk_attr_p->max_value = *db_data_p;
}
}
}
}
cls_info_p->tot_objects++;
disk_repr_p->num_objects++;
scan_rc = heap_next (thread_p, &(cls_info_p->hfid), class_id_p, &oid,
&recdes, hf_scan_cache_p, PEEK);
}
if (scan_rc == S_ERROR)
{
goto error;
}
heap_attrinfo_end (thread_p, hf_cache_attr_info_p);
if (heap_scancache_end (thread_p, hf_scan_cache_p) != NO_ERROR)
{
goto error;
}
/* update the index statistics for each attribute */
for (i = 0; i < disk_repr_p->n_fixed + disk_repr_p->n_variable; i++)
{
if (i < disk_repr_p->n_fixed)
{
disk_attr_p = disk_repr_p->fixed + i;
}
else
{
disk_attr_p = disk_repr_p->variable + (i - disk_repr_p->n_fixed);
}
for (j = 0, btree_stats_p = disk_attr_p->bt_stats;
j < disk_attr_p->n_btstats; j++, btree_stats_p++)
{
if (btree_get_stats (thread_p, &btree_stats_p->btid, btree_stats_p,
true) != NO_ERROR)
{
goto error;
}
}
}
/* replace the current disk representation structure/information in the
catalog with the newly computed statistics */
if (catalog_add_representation (thread_p, class_id_p, repr_id, disk_repr_p)
!= NO_ERROR)
{
goto error;
}
cls_info_p->time_stamp = stats_get_time_stamp ();
if (catalog_add_class_info (thread_p, class_id_p, cls_info_p) != NO_ERROR)
{
goto error;
}
if (disk_repr_p)
{
catalog_free_representation (disk_repr_p);
}
if (cls_info_p)
{
catalog_free_class_info (cls_info_p);
}
return NO_ERROR;
error:
if (hf_cache_attr_info_p)
{
heap_attrinfo_end (thread_p, hf_cache_attr_info_p);
}
if (hf_scan_cache_p)
{
(void) heap_scancache_end (thread_p, hf_scan_cache_p);
}
if (disk_repr_p)
{
catalog_free_representation (disk_repr_p);
}
if (cls_info_p)
{
catalog_free_class_info (cls_info_p);
}
return er_errid ();
}
