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Commit 144f82a9 authored by Igor Babaev's avatar Igor Babaev
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Addressed the feedback from the review of Monty on the cumulative patch for 

mwl#21.
parent ac984f41
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Showing with 527 additions and 412 deletions
include/my_tree.h
View file @ 144f82a9
......@@ -30,6 +30,15 @@ extern "C" {
#define tree_set_pointer(element,ptr) *((uchar **) (element+1))=((uchar*) (ptr))
/*
A tree with its flag set to TREE_ONLY_DUPS behaves differently on inserting
an element that is not in the tree:
the element is not added at all, but instead tree_insert() returns a special
address TREE_ELEMENT_UNIQUE as an indication that the function has not failed
due to lack of memory.
*/
#define TREE_ELEMENT_UNIQUE ((TREE_ELEMENT *) 1)
#define TREE_NO_DUPS 1
#define TREE_ONLY_DUPS 2
......
sql/filesort.cc
View file @ 144f82a9
......@@ -141,9 +141,6 @@ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length,
/* filesort cannot handle zero-length records. */
DBUG_ASSERT(param.sort_length);
param.ref_length= table->file->ref_length;
param.min_dupl_count= 0;
param.addon_field= 0;
param.addon_length= 0;
if (!(table->file->ha_table_flags() & HA_FAST_KEY_READ) &&
!table->fulltext_searched && !sort_positions)
{
......@@ -1197,8 +1194,11 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
QUEUE queue;
qsort2_cmp cmp;
void *first_cmp_arg;
volatile THD::killed_state *killed= &current_thd->killed;
element_count dupl_count;
uchar *src;
THD::killed_state not_killable;
uchar *unique_buff= param->unique_buff;
volatile THD::killed_state *killed= &current_thd->killed;
DBUG_ENTER("merge_buffers");
status_var_increment(current_thd->status_var.filesort_merge_passes);
......@@ -1213,13 +1213,13 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
rec_length= param->rec_length;
res_length= param->res_length;
sort_length= param->sort_length;
element_count dupl_count;
uchar *src;
uint dupl_count_ofs= rec_length-sizeof(element_count);
uint min_dupl_count= param->min_dupl_count;
offset= rec_length-
(flag && min_dupl_count ? sizeof(dupl_count) : 0)-res_length;
bool check_dupl_count= flag && min_dupl_count;
offset= (rec_length-
(flag && min_dupl_count ? sizeof(dupl_count) : 0)-res_length);
uint wr_len= flag ? res_length : rec_length;
uint wr_offset= flag ? offset : 0;
maxcount= (ulong) (param->keys/((uint) (Tb-Fb) +1));
to_start_filepos= my_b_tell(to_file);
strpos= sort_buffer;
......@@ -1228,7 +1228,7 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
/* The following will fire if there is not enough space in sort_buffer */
DBUG_ASSERT(maxcount!=0);
if (param->unique_buff)
if (unique_buff)
{
cmp= param->compare;
first_cmp_arg= (void *) &param->cmp_context;
......@@ -1253,25 +1253,22 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
queue_insert(&queue, (uchar*) buffpek);
}
if (param->unique_buff)
if (unique_buff)
{
/*
Called by Unique::get()
Copy the first argument to param->unique_buff for unique removal.
Copy the first argument to unique_buff for unique removal.
Store it also in 'to_file'.
This is safe as we know that there is always more than one element
in each block to merge (This is guaranteed by the Unique:: algorithm
*/
buffpek= (BUFFPEK*) queue_top(&queue);
memcpy(param->unique_buff, buffpek->key, rec_length);
memcpy(unique_buff, buffpek->key, rec_length);
if (min_dupl_count)
memcpy(&dupl_count, param->unique_buff+dupl_count_ofs,
memcpy(&dupl_count, unique_buff+dupl_count_ofs,
sizeof(dupl_count));
buffpek->key+= rec_length;
if (! --buffpek->mem_count)
{
if (!(error= (int) read_to_buffer(from_file,buffpek,
if (!(error= (int) read_to_buffer(from_file, buffpek,
rec_length)))
{
VOID(queue_remove(&queue,0));
......@@ -1297,7 +1294,7 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
src= buffpek->key;
if (cmp) // Remove duplicates
{
if (!(*cmp)(first_cmp_arg, &(param->unique_buff),
if (!(*cmp)(first_cmp_arg, &unique_buff,
(uchar**) &buffpek->key))
{
if (min_dupl_count)
......@@ -1310,24 +1307,32 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
}
if (min_dupl_count)
{
memcpy(param->unique_buff+dupl_count_ofs, &dupl_count,
memcpy(unique_buff+dupl_count_ofs, &dupl_count,
sizeof(dupl_count));
}
src= param->unique_buff;
src= unique_buff;
}
if (!flag || !min_dupl_count || dupl_count >= min_dupl_count)
/*
Do not write into the output file if this is the final merge called
for a Unique object used for intersection and dupl_count is less
than min_dupl_count.
If the Unique object is used to intersect N sets of unique elements
then for any element:
dupl_count >= N <=> the element is occurred in each of these N sets.
*/
if (!check_dupl_count || dupl_count >= min_dupl_count)
{
if (my_b_write(to_file, src+(flag ? offset : 0), wr_len))
if (my_b_write(to_file, src+wr_offset, wr_len))
{
error=1; goto err; /* purecov: inspected */
}
}
if (cmp)
{
memcpy(param->unique_buff, (uchar*) buffpek->key, rec_length);
memcpy(unique_buff, (uchar*) buffpek->key, rec_length);
if (min_dupl_count)
memcpy(&dupl_count, param->unique_buff+dupl_count_ofs,
memcpy(&dupl_count, unique_buff+dupl_count_ofs,
sizeof(dupl_count));
}
if (!--max_rows)
......@@ -1340,7 +1345,7 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
buffpek->key+= rec_length;
if (! --buffpek->mem_count)
{
if (!(error= (int) read_to_buffer(from_file,buffpek,
if (!(error= (int) read_to_buffer(from_file, buffpek,
rec_length)))
{
VOID(queue_remove(&queue,0));
......@@ -1363,7 +1368,7 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
*/
if (cmp)
{
if (!(*cmp)(first_cmp_arg, &(param->unique_buff), (uchar**) &buffpek->key))
if (!(*cmp)(first_cmp_arg, &unique_buff, (uchar**) &buffpek->key))
{
if (min_dupl_count)
{
......@@ -1376,13 +1381,13 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
}
if (min_dupl_count)
memcpy(param->unique_buff+dupl_count_ofs, &dupl_count,
memcpy(unique_buff+dupl_count_ofs, &dupl_count,
sizeof(dupl_count));
if (!flag || !min_dupl_count || dupl_count >= min_dupl_count)
if (!check_dupl_count || dupl_count >= min_dupl_count)
{
src= param->unique_buff;
if (my_b_write(to_file, src+(flag ? offset : 0), wr_len))
src= unique_buff;
if (my_b_write(to_file, src+wr_offset, wr_len))
{
error=1; goto err; /* purecov: inspected */
}
......@@ -1404,7 +1409,7 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
max_rows-= buffpek->mem_count;
if (flag == 0)
{
if (my_b_write(to_file,(uchar*) buffpek->key,
if (my_b_write(to_file, (uchar*) buffpek->key,
(rec_length*buffpek->mem_count)))
{
error= 1; goto err; /* purecov: inspected */
......@@ -1418,11 +1423,12 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
src != end ;
src+= rec_length)
{
if (flag && min_dupl_count &&
memcmp(&min_dupl_count, src+dupl_count_ofs,
sizeof(dupl_count_ofs))<0)
continue;
if (check_dupl_count)
{
memcpy((uchar *) &dupl_count, src+dupl_count_ofs, sizeof(dupl_count));
if (dupl_count < min_dupl_count)
continue;
}
if (my_b_write(to_file, src, wr_len))
{
error=1; goto err;
......@@ -1430,7 +1436,7 @@ int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
}
}
}
while ((error=(int) read_to_buffer(from_file,buffpek, rec_length))
while ((error=(int) read_to_buffer(from_file, buffpek, rec_length))
!= -1 && error != 0);
end:
......
sql/mysql_priv.h
View file @ 144f82a9
......@@ -340,6 +340,9 @@ class Default_object_creation_ctx : public Object_creation_ctx
*/
#define TIME_FOR_COMPARE_ROWID (TIME_FOR_COMPARE*100)
/* cost1 is better that cost2 only if cost1 + COST_EPS < cost2 */
#define COST_EPS 0.001
/*
For sequential disk seeks the cost formula is:
DISK_SEEK_BASE_COST + DISK_SEEK_PROP_COST * #blocks_to_skip
......
sql/opt_range.cc
View file @ 144f82a9
This diff is collapsed.
sql/opt_range.h
View file @ 144f82a9
......@@ -328,6 +328,7 @@ class QUICK_SELECT_I
selects output and/or can produce output suitable for merging.
*/
virtual void add_info_string(String *str) {}
/*
Return 1 if any index used by this quick select
uses field which is marked in passed bitmap.
......@@ -406,9 +407,11 @@ class QUICK_RANGE_SELECT : public QUICK_SELECT_I
QUICK_RANGE_SELECT *pk_quick_select,
READ_RECORD *read_record,
bool intersection,
key_map *filtered_scans,
Unique **unique_ptr);
friend class QUICK_SELECT_DESC;
friend class QUICK_INDEX_SORT_SELECT;
friend class QUICK_INDEX_MERGE_SELECT;
friend class QUICK_INDEX_INTERSECT_SELECT;
friend class QUICK_ROR_INTERSECT_SELECT;
......@@ -464,40 +467,44 @@ class QUICK_RANGE_SELECT_GEOM: public QUICK_RANGE_SELECT
/*
QUICK_INDEX_MERGE_SELECT - index_merge access method quick select.
QUICK_INDEX_SORT_SELECT is the base class for the common functionality of:
- QUICK_INDEX_MERGE_SELECT, access based on multi-index merge/union
- QUICK_INDEX_INTERSECT_SELECT, access based on multi-index intersection
QUICK_INDEX_MERGE_SELECT uses
QUICK_INDEX_SORT_SELECT uses
* QUICK_RANGE_SELECTs to get rows
* Unique class to remove duplicate rows
* Unique class
- to remove duplicate rows for QUICK_INDEX_MERGE_SELECT
- to intersect rows for QUICK_INDEX_INTERSECT_SELECT
INDEX MERGE OPTIMIZER
Current implementation doesn't detect all cases where index_merge could
Current implementation doesn't detect all cases where index merge could
be used, in particular:
* index_merge will never be used if range scan is possible (even if
range scan is more expensive)
* index_merge+'using index' is not supported (this the consequence of
* index merge+'using index' is not supported (this the consequence of
the above restriction)
* If WHERE part contains complex nested AND and OR conditions, some ways
to retrieve rows using index_merge will not be considered. The choice
to retrieve rows using index merge will not be considered. The choice
of read plan may depend on the order of conjuncts/disjuncts in WHERE
part of the query, see comments near imerge_list_or_list and
SEL_IMERGE::or_sel_tree_with_checks functions for details.
* There is no "index_merge_ref" method (but index_merge on non-first
* There is no "index_merge_ref" method (but index merge on non-first
table in join is possible with 'range checked for each record').
See comments around SEL_IMERGE class and test_quick_select for more
details.
ROW RETRIEVAL ALGORITHM
index_merge uses Unique class for duplicates removal. index_merge takes
advantage of Clustered Primary Key (CPK) if the table has one.
The index_merge algorithm consists of two phases:
index merge/intersection uses Unique class for duplicates removal.
index merge/intersection takes advantage of Clustered Primary Key (CPK)
if the table has one.
The index merge/intersection algorithm consists of two phases:
Phase 1
(implemented by a QUICK_INDEX_MERGE_SELECT::read_keys_and_merge call):
Phase 1 (implemented in QUICK_INDEX_MERGE_SELECT::prepare_unique):
prepare()
{
activate 'index only';
......@@ -511,32 +518,31 @@ class QUICK_RANGE_SELECT_GEOM: public QUICK_RANGE_SELECT
deactivate 'index only';
}
Phase 2 (implemented as sequence of QUICK_INDEX_MERGE_SELECT::get_next
calls):
Phase 2
(implemented as sequence of QUICK_INDEX_MERGE_SELECT::get_next calls):
fetch()
{
retrieve all rows from row pointers stored in Unique;
retrieve all rows from row pointers stored in Unique
(merging/intersecting them);
free Unique;
retrieve all rows for CPK scan;
if (! intersection)
retrieve all rows for CPK scan;
}
*/
class QUICK_INDEX_MERGE_SELECT : public QUICK_SELECT_I
class QUICK_INDEX_SORT_SELECT : public QUICK_SELECT_I
{
protected:
Unique *unique;
public:
QUICK_INDEX_MERGE_SELECT(THD *thd, TABLE *table);
~QUICK_INDEX_MERGE_SELECT();
QUICK_INDEX_SORT_SELECT(THD *thd, TABLE *table);
~QUICK_INDEX_SORT_SELECT();
int init();
int reset(void);
int get_next();
bool reverse_sorted() { return false; }
bool unique_key_range() { return false; }
int get_type() { return QS_TYPE_INDEX_MERGE; }
void add_keys_and_lengths(String *key_names, String *used_lengths);
void add_info_string(String *str);
bool is_keys_used(const MY_BITMAP *fields);
#ifndef DBUG_OFF
void dbug_dump(int indent, bool verbose);
......@@ -544,60 +550,54 @@ class QUICK_INDEX_MERGE_SELECT : public QUICK_SELECT_I
bool push_quick_back(QUICK_RANGE_SELECT *quick_sel_range);
/* range quick selects this index_merge read consists of */
/* range quick selects this index merge/intersect consists of */
List<QUICK_RANGE_SELECT> quick_selects;
/* quick select that uses clustered primary key (NULL if none) */
QUICK_RANGE_SELECT* pk_quick_select;
/* true if this select is currently doing a clustered PK scan */
bool doing_pk_scan;
MEM_ROOT alloc;
THD *thd;
int read_keys_and_merge();
virtual int read_keys_and_merge()= 0;
/* used to get rows collected in Unique */
READ_RECORD read_record;
};
class QUICK_INDEX_INTERSECT_SELECT : public QUICK_SELECT_I
class QUICK_INDEX_MERGE_SELECT : public QUICK_INDEX_SORT_SELECT
{
Unique *unique;
private:
/* true if this select is currently doing a clustered PK scan */
bool doing_pk_scan;
protected:
int read_keys_and_merge();
public:
QUICK_INDEX_INTERSECT_SELECT(THD *thd, TABLE *table);
~QUICK_INDEX_INTERSECT_SELECT();
QUICK_INDEX_MERGE_SELECT(THD *thd, TABLE *table)
:QUICK_INDEX_SORT_SELECT(thd, table) {}
int init();
int reset(void);
int get_next();
bool reverse_sorted() { return false; }
bool unique_key_range() { return false; }
int get_type() { return QS_TYPE_INDEX_INTERSECT; }
int get_next();
int get_type() { return QS_TYPE_INDEX_MERGE; }
void add_keys_and_lengths(String *key_names, String *used_lengths);
void add_info_string(String *str);
bool is_keys_used(const MY_BITMAP *fields);
#ifndef DBUG_OFF
void dbug_dump(int indent, bool verbose);
#endif
bool push_quick_back(QUICK_RANGE_SELECT *quick_sel_range);
/* range quick selects this index_merge read consists of */
List<QUICK_RANGE_SELECT> quick_selects;
/* quick select that uses clustered primary key (NULL if none) */
QUICK_RANGE_SELECT* pk_quick_select;
/* true if this select is currently doing a clustered PK scan */
bool doing_pk_scan;
};
MEM_ROOT alloc;
THD *thd;
class QUICK_INDEX_INTERSECT_SELECT : public QUICK_INDEX_SORT_SELECT
{
protected:
int read_keys_and_merge();
/* used to get rows collected in Unique */
READ_RECORD read_record;
public:
QUICK_INDEX_INTERSECT_SELECT(THD *thd, TABLE *table)
:QUICK_INDEX_SORT_SELECT(thd, table) {}
key_map filtered_scans;
int get_next();
int get_type() { return QS_TYPE_INDEX_INTERSECT; }
void add_keys_and_lengths(String *key_names, String *used_lengths);
void add_info_string(String *str);
};
......
sql/sql_class.h
View file @ 144f82a9
......@@ -2998,7 +2998,7 @@ class Unique :public Sql_alloc
bool flush();
uint size;
uint full_size;
uint min_dupl_count;
uint min_dupl_count; /* always 0 for unions, > 0 for intersections */
public:
ulong elements;
......@@ -3022,6 +3022,7 @@ class Unique :public Sql_alloc
bool get(TABLE *table);
/* Cost of searching for an element in the tree */
inline static double get_search_cost(uint tree_elems, uint compare_factor)
{
return log((double) tree_elems) / (compare_factor * M_LN2);
......
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