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Code Activity

* New index_merge EXPLAIN output format

Browse Source 
* Fixed a problem with wrong query results for partially covering keys in ROR-index_merge
 * ROR-intersection retrieval plan choice algorithm now uses less disk IO
   - and properly processes clustered PK range scans 
 * Fixed several minor range optimizer problems
 * Added more comments
 * Code cleanup


mysql-test/r/index_merge.result:
  New index_merge EXPLAIN output format changes
mysql-test/r/index_merge_innodb.result:
  New index_merge EXPLAIN output format changes
mysql-test/r/index_merge_ror.result:
  New index_merge EXPLAIN output format changes
  Added test for scans on keys that cover fields partially
  Fixed a minor ROR optimizer problem
mysql-test/r/index_merge_ror_cpk.result:
  More tests added
mysql-test/t/index_merge_ror.test:
  New index_merge EXPLAIN output format changes
  Added test for scans on keys that cover fields partially
  Fixed a minor ROR optimizer problem
mysql-test/t/index_merge_ror_cpk.test:
  More tests added
mysys/my_bitmap.c:
  Comments added, code cleanup
sql/opt_range.cc:
  Comments added, code cleanup
  Numerous fixes, see changeset description
sql/opt_range.h:
  Comments added, code cleanup
  New index_merge EXPLAIN output format related changes
sql/sql_select.cc:
  Comments added, code cleanup
  New index_merge EXPLAIN output
This commit is contained in:
unknown
2004-05-29 02:04:01 +04:00
parent aa2bd8ec73
commit 1ce1880204
10 changed files with 1142 additions and 483 deletions
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195
sql/opt_range.h
View File

@ -77,27 +77,59 @@ public:
ha_rows records; /* estimate of # of records to be retrieved */
double read_time; /* time to perform this retrieval */
TABLE *head;
/*
index this quick select uses, or MAX_KEY for quick selects
Index this quick select uses, or MAX_KEY for quick selects
that use several indexes
*/
uint index;
/* applicable iff index!= MAX_KEY */
uint max_used_key_length, used_key_parts;
/*
Total length of first used_key_parts parts of the key.
Applicable if index!= MAX_KEY.
*/
uint max_used_key_length;
/*
Max. number of (first) key parts this quick select uses for retrieval.
eg. for "(key1p1=c1 AND key1p2=c2) OR key1p1=c2" used_key_parts == 2.
Applicable if index!= MAX_KEY.
*/
uint used_key_parts;
QUICK_SELECT_I();
virtual ~QUICK_SELECT_I(){};
/*
Call init() immediately after creation of quick select. if init() call
fails, reset() or get_next() must not be called.
/*
Do post-constructor initialization.
SYNOPSIS
init()
init() performs initializations that should have been in constructor if
it was possible to return errors from constructors. The join optimizer may
create and then delete quick selects without retrieving any rows so init()
must not contain any IO or CPU intensive code.
If init() call fails the only valid action is to delete this quick select,
reset() and get_next() must not be called.
RETURN
0 OK
other Error code
*/
virtual int init() = 0;
/*
Call reset() before first get_next call. get_next must not be called if
reset() call fails.
Initialize quick select for row retrieval.
SYNOPSIS
reset()
reset() should be called when it is certain that row retrieval will be
necessary. This call may do heavyweight initialization like buffering first
N records etc. If reset() call fails get_next() must not be called.
RETURN
0 OK
other Error code
*/
virtual int reset(void) = 0;
virtual int get_next() = 0; /* get next record to retrieve */
@ -117,30 +149,54 @@ public:
virtual int get_type() = 0;
/*
Initialize this quick select as a child of a index union or intersection
scan. This call replaces init() call.
Initialize this quick select as a merged scan inside a ROR-union or a ROR-
intersection scan. The caller must not additionally call init() if this
function is called.
SYNOPSIS
init_ror_merged_scan()
reuse_handler quick select may use (q: psergey??)
(q: is this natural that we do it this way)
NOTES
psergey?
*/
virtual int init_ror_child_scan(bool reuse_handler)
virtual int init_ror_merged_scan(bool reuse_handler)
{ DBUG_ASSERT(0); return 1; }
virtual void cleanup_ror_child_scan() { DBUG_ASSERT(0); }
/* Save ROWID of last retrieved row in file->ref. (psergey: or table->ref?) */
virtual void save_last_pos(){};
/*
Fill key_names with list of keys this quick select used;
fill used_lenghth with correponding used lengths.
Append comma-separated list of keys this quick select uses to key_names;
append comma-separated list of corresponding used lengths to used_lengths.
This is used by select_describe.
*/
virtual void fill_keys_and_lengths(String *key_names,
String *used_lengths)=0;
virtual void add_keys_and_lengths(String *key_names,
String *used_lengths)=0;
/*
Append text representation of quick select structure (what and how is
merged) to str. The result is added to "Extra" field in EXPLAIN output.
This function is implemented only by quick selects that merge other quick
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
a) uses field that is listed in passed field list or
b) is automatically updated (like a timestamp)
*/
virtual bool check_if_keys_used(List<Item> *fields);
/*
rowid of last row retrieved by this quick select. This is used only
when doing ROR-index_merge selects
rowid of last row retrieved by this quick select. This is used only when
doing ROR-index_merge selects
*/
byte *last_rowid;
/*
Table record buffer used by this quick select.
Currently this is always the same as head->record[0]. psergey: check that!
*/
byte *record;
#ifndef DBUG_OFF
/*
@ -155,6 +211,10 @@ public:
struct st_qsel_param;
class SEL_ARG;
/*
Quick select that does a range scan on a single key. The records are
returned in key order.
*/
class QUICK_RANGE_SELECT : public QUICK_SELECT_I
{
protected:
@ -163,7 +223,11 @@ public:
int error;
protected:
handler *file;
bool free_file; /* if true, this quick select "owns" file and will free it */
/*
If true, this quick select has its "own" handler object which should be
closed no later then this quick select is deleted.
*/
bool free_file;
protected:
friend
@ -207,15 +271,16 @@ public:
int get_next();
bool reverse_sorted() { return 0; }
bool unique_key_range();
int init_ror_child_scan(bool reuse_handler);
int init_ror_merged_scan(bool reuse_handler);
void save_last_pos()
{
file->position(record);
};
int get_type() { return QS_TYPE_RANGE; }
void fill_keys_and_lengths(String *key_names, String *used_lengths);
void add_keys_and_lengths(String *key_names, String *used_lengths);
void add_info_string(String *str);
#ifndef DBUG_OFF
virtual void dbug_dump(int indent, bool verbose);
void dbug_dump(int indent, bool verbose);
#endif
};
@ -291,10 +356,11 @@ public:
bool reverse_sorted() { return false; }
bool unique_key_range() { return false; }
int get_type() { return QS_TYPE_INDEX_MERGE; }
void fill_keys_and_lengths(String *key_names, String *used_lengths);
void add_keys_and_lengths(String *key_names, String *used_lengths);
void add_info_string(String *str);
bool check_if_keys_used(List<Item> *fields);
#ifndef DBUG_OFF
virtual void dbug_dump(int indent, bool verbose);
void dbug_dump(int indent, bool verbose);
#endif
bool push_quick_back(QUICK_RANGE_SELECT *quick_sel_range);
@ -317,7 +383,6 @@ public:
THD *thd;
int prepare_unique();
bool reset_called;
/* used to get rows collected in Unique */
READ_RECORD read_record;
@ -326,9 +391,22 @@ public:
/*
Rowid-Ordered Retrieval (ROR) index intersection quick select.
This quick select produces an intersection of records returned by several
QUICK_RANGE_SELECTs that return data ordered by rowid.
This quick select produces intersection of row sequences returned
by several QUICK_RANGE_SELECTs it "merges".
All merged QUICK_RANGE_SELECTs must return rowids in rowid order.
QUICK_ROR_INTERSECT_SELECT will return rows in rowid order, too.
All merged quick selects retrieve {rowid, covered_fields} tuples (not full
table records).
QUICK_ROR_INTERSECT_SELECT retrieves full records if it is not being used
by QUICK_ROR_INTERSECT_SELECT and all merged quick selects together don't
cover needed all fields.
If one of the merged quick selects is a Clustered PK range scan, it is
used only to filter rowid sequence produced by other merged quick selects.
*/
class QUICK_ROR_INTERSECT_SELECT : public QUICK_SELECT_I
{
public:
@ -343,28 +421,46 @@ public:
bool reverse_sorted() { return false; }
bool unique_key_range() { return false; }
int get_type() { return QS_TYPE_ROR_INTERSECT; }
void fill_keys_and_lengths(String *key_names, String *used_lengths);
void add_keys_and_lengths(String *key_names, String *used_lengths);
void add_info_string(String *str);
bool check_if_keys_used(List<Item> *fields);
#ifndef DBUG_OFF
virtual void dbug_dump(int indent, bool verbose);
void dbug_dump(int indent, bool verbose);
#endif
int init_ror_child_scan(bool reuse_handler);
int init_ror_merged_scan(bool reuse_handler);
bool push_quick_back(QUICK_RANGE_SELECT *quick_sel_range);
/* range quick selects this intersection consists of */
/*
Range quick selects this intersection consists of, not including
cpk_quick.
*/
List<QUICK_RANGE_SELECT> quick_selects;
/*
Merged quick select that uses Clustered PK, if there is one. This quick
select is not used for row retrieval, it is used for row retrieval.
*/
QUICK_RANGE_SELECT *cpk_quick;
MEM_ROOT alloc;
THD *thd;
bool reset_called;
bool need_to_fetch_row;
MEM_ROOT alloc; /* Memory pool for this and merged quick selects data. */
THD *thd; /* current thread */
bool need_to_fetch_row; /* if true, do retrieve full table records. */
};
/*
Rowid-Ordered Retrieval index union select.
This quick select produces union of row sequences returned by several
quick select it "merges".
All merged quick selects must return rowids in rowid order.
QUICK_ROR_UNION_SELECT will return rows in rowid order, too.
All merged quick selects are set not to retrieve full table records.
ROR-union quick select always retrieves full records.
*/
class QUICK_ROR_UNION_SELECT : public QUICK_SELECT_I
{
public:
@ -377,33 +473,30 @@ public:
bool reverse_sorted() { return false; }
bool unique_key_range() { return false; }
int get_type() { return QS_TYPE_ROR_UNION; }
void fill_keys_and_lengths(String *key_names, String *used_lengths);
void add_keys_and_lengths(String *key_names, String *used_lengths);
void add_info_string(String *str);
bool check_if_keys_used(List<Item> *fields);
#ifndef DBUG_OFF
virtual void dbug_dump(int indent, bool verbose);
void dbug_dump(int indent, bool verbose);
#endif
bool push_quick_back(QUICK_SELECT_I *quick_sel_range);
/* range quick selects this index_merge read consists of */
List<QUICK_SELECT_I> quick_selects;
List<QUICK_SELECT_I> quick_selects; /* Merged quick selects */
QUEUE queue;
MEM_ROOT alloc;
QUEUE queue; /* Priority queue for merge operation */
MEM_ROOT alloc; /* Memory pool for this and merged quick selects data. */
THD *thd;
byte *cur_rowid;
byte *prev_rowid;
uint rowid_length;
bool reset_called;
bool have_prev_rowid;
THD *thd; /* current thread */
byte *cur_rowid; /* buffer used in get_next() */
byte *prev_rowid; /* rowid of last row returned by get_next() */
bool have_prev_rowid; /* true if prev_rowid has valid data */
uint rowid_length; /* table rowid length */
private:
static int queue_cmp(void *arg, byte *val1, byte *val2);
};
class QUICK_SELECT_DESC: public QUICK_RANGE_SELECT
{
public: