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DISTINCT optimization

Browse source 
Fixes when using column privileges
Manual updates
This commit is contained in:
monty@tramp.mysql.fi 2000-10-06 21:15:03 +03:00
parent a434c8d244
commit 207548a836
8 changed files with 283 additions and 131 deletions
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26
BitKeeper/etc/logging_ok
View file

@ -1,25 +1 @@
bk@work.mysql.com
davida@work.mysql.com
jamppa@work.mysql.com
jcole@ham.spaceapes.com
jcole@jcole.burghcom.com
jcole@nslinux.bedford.progress.com
jcole@tetra.bedford.progress.com
jcole@tetra.spaceapes.com
matt@work.mysql.com
monty@donna.mysql.com
monty@work.mysql.com
mwagner@evoq.home.mwagner.org
nusphere@main.burghcom.com
paul@central.snake.net
paul@work.mysql.com
sasha@mysql.sashanet.com
sasha@work.mysql.com
serg@infomag.ape.relarn.ru
serg@work.mysql.com
sinisa@work.mysql.com
spurr@nslinux.bedford.progress.com
tim@localhost.polyesthetic.msg
tim@threads.polyesthetic.msg
tim@work.mysql.com
tonu@work.mysql.com
monty@tramp.mysql.fi

178
Docs/manual.texi
View file

@ -305,14 +305,14 @@ Post-installation Setup and Testing
* Command-line options:: Command-line options
* Option files:: Option files
Is there anything special to do when upgrading/downgrading MySQL?
Is There Anything Special to Do when Upgrading/Downgrading MySQL?
* Upgrading-from-3.22:: Upgrading from a 3.22 version to 3.23
* Upgrading-from-3.21:: Upgrading from a 3.21 version to 3.22
* Upgrading-from-3.20:: Upgrading from a 3.20 version to 3.21
* Upgrading-to-arch:: Upgrading to another architecture
How standards-compatible is MySQL?
How Standards-compatible Is MySQL?
* Extensions to ANSI:: @strong{MySQL} extensions to ANSI SQL92
* Ansi mode:: Running @strong{MySQL} in ANSI mode
@ -321,7 +321,7 @@ How standards-compatible is MySQL?
* Standards:: What standards does @strong{MySQL} follow?
* Commit-rollback:: How to cope without @code{COMMIT}-@code{ROLLBACK}
Functionality missing from MySQL
Functionality Missing from MySQL
* Missing Sub-selects:: Sub-selects
* Missing SELECT INTO TABLE:: @code{SELECT INTO TABLE}
@ -335,7 +335,7 @@ Foreign Keys
* Broken Foreign KEY:: Reasons NOT to use foreign keys
The MySQL access privilege system
The MySQL Access Privilege System
* General security:: General security
* Security:: How to make @strong{MySQL} secure against crackers
@ -353,7 +353,7 @@ The MySQL access privilege system
* Passwords:: How to set up passwords
* Access denied:: Causes of @code{Access denied} errors
MySQL language reference
MySQL Language Reference
* Literals:: Literals: how to write strings and numbers
* Variables:: User variables
@ -394,7 +394,7 @@ MySQL language reference
* CREATE FUNCTION:: @code{CREATE FUNCTION} syntax
* Reserved words:: Is @strong{MySQL} picky about reserved words?
Literals: how to write strings and numbers
Literals: How to Write Strings and Numbers
* String syntax:: Strings
* Number syntax:: Numbers
@ -402,11 +402,11 @@ Literals: how to write strings and numbers
* NULL values:: @code{NULL} values
* Legal names:: Database, table, index, column and alias names
Database, table, index, column and alias names
Database, Table, Index, Column, and Alias Names
* Name case sensitivity:: Case sensitivity in names
Column types
Column Types
* Storage requirements:: Column type storage requirements
* Numeric types:: Numeric types
@ -417,21 +417,21 @@ Column types
* Multiple-column indexes:: Multiple-column indexes
* Other-vendor column types:: Using column types from other database engines
Date and time types
Date and Time Types
* Y2K issues:: Y2K issues and date types
* DATETIME:: The @code{DATETIME}, @code{DATE} and @code{TIMESTAMP} types
* TIME:: The @code{TIME} type
* YEAR:: The @code{YEAR} type
String types
String Types
* CHAR:: The @code{CHAR} and @code{VARCHAR} types
* BLOB:: The @code{BLOB} and @code{TEXT} types
* ENUM:: The @code{ENUM} type
* SET:: The @code{SET} type
Functions for use in @code{SELECT} and @code{WHERE} clauses
Functions for Use in @code{SELECT} and @code{WHERE} Clauses
* Grouping functions:: Grouping functions
* Arithmetic functions:: Normal arithmetic operations
@ -447,7 +447,7 @@ Functions for use in @code{SELECT} and @code{WHERE} clauses
* Miscellaneous functions:: Miscellaneous functions
* Group by functions:: Functions for @code{GROUP BY} clause
@code{CREATE TABLE} syntax
@code{CREATE TABLE} Syntax
* Silent column changes:: Silent column changes
@ -580,6 +580,7 @@ Speed of queries that access or update data
* Estimating performance:: Estimating query performance
* SELECT speed:: Speed of @code{SELECT} queries
* Where optimizations:: How MySQL optimizes @code{WHERE} clauses
* DISTINCT optimization::
* LEFT JOIN optimization:: How MySQL optimizes @code{LEFT JOIN}
* LIMIT optimization:: How MySQL optimizes @code{LIMIT}
* Insert speed:: Speed of @code{INSERT} queries
@ -4393,14 +4394,47 @@ last version number is newer than yours). We have tried to fix only
fatal bugs and make small, relatively safe changes to that version.
@end itemize
The second decision to make is whether you want to use a source distribution or
a binary distribution:
The second decision to make is whether you want to use a source
distribution or a binary distribution. In most cases you should probably
use a binary distribution, if there exist one for your platform, as this
is generally, it will be easier to install than a source distribution.
In the following cases you will probably be better of with a source
installation:
@itemize @bullet
@item
If you want to run @strong{MySQL} on a platform for which a current binary
distribution exists, use that. Generally, it will be easier to install
than a source distribution.
If you want to install @strong{MySQL} at some explicit location. (The standard
binary distributions are 'ready to run' at any place, but you may want
to get even more flexibility).
@item
If you want to configure @code{mysqld} with some extra feature that is NOT in
the standard binary distributions. Here follows a list of the most common
extra options that you may want to use
@itemize @bullet
@item --with-berkeley-db
@item --with-raid
@item --with-libwrap
@item --with-named-z-lib (This is done for some of the binaries)
@item --with-debugging[=full]
@end itemize
@item
The default binary distribution is normally compiled with support
for all characters sets and should work on a variety of processors from
the same processor family.
If you want a faster @strong{MySQL} server you may want to recompile it
with support for only the character sets you need, use a better compiler
(like pgcc) or use compiler options that are better optimized for your
processor.
@item
If you have found a bug and reported it to the @strong{MySQL}
development team you will probably got a patch that you need to apply to
the source distribution to get the bug fixed.
@item
If you want to read (and/or modify) the C and C++ code that makes up
@ -9122,6 +9156,7 @@ for clients from option files.
@item @strong{Filename} @tab @strong{Purpose}
@item @code{/etc/my.cnf} @tab Global options
@item @code{DATADIR/my.cnf} @tab Server-specific options
@item @code{defaults-extra-file} @tab The file specified with --defaults-extra-file=#
@item @code{~/.my.cnf} @tab User-specific options
@end multitable
@ -9233,15 +9268,19 @@ there are sample configuration files for small, medium, large, and very
large systems. You can copy @file{my-xxxx.cnf} to your home directory
(rename the copy to @file{.my.cnf}) to experiment with this.
To tell a @strong{MySQL} program not to read any option files, specify
@code{--no-defaults} as the first option on the command line. This
@strong{MUST} be the first option or it will have no effect!
If you want to check which options are used, you can give the option
@code{--print-defaults} as the first option.
All @strong{MySQL} clients that support option files support the
following options:
If you want to force the use of a specific config file, you can use the option
@code{--defaults-file=full-path-to-default-file}. If you do this, only the
specified file will be read.
@multitable @columnfractions .40 .60
@item --no-defaults @tab Don't read any option files.
@item --print-defaults @tab Print the program name and all options that it will get.
@item --defaults-file=full-path-to-default-file @tab Only use the given configuration file.
@item --defaults-extra-file=full-path-to-default-file @tab Read this configuration file after the global configuration file but before the user configuration file.
@end multitable
Note that the above options must be first on the command line to work!
@code{--print-defaults} may however be used directly after the
@code{--defaults-xxx-file} commands.
Note for developers: Option file handling is implemented simply by
processing all matching options (that is, options in the appropriate group)
@ -9252,6 +9291,19 @@ read option files, you need add only two lines to give it that capability.
Check the source code of any of the standard @strong{MySQL} clients to see
how to do this.
In shell scripts you can use the @file{my_print_defaults} command to parse the
config files:
@example
shell> my_print_defaults client mysql
--port=3306
--socket=/tmp/mysql.sock
--no-auto-rehash
@end example
The above output contains all options for the groups 'client' and 'mysql'.
@node Upgrade, , Post-installation, Installing
@section Is There Anything Special to Do when Upgrading/Downgrading MySQL?
@cindex upgrading
@ -20035,6 +20087,9 @@ resolve the query. Here follows an explanation of the different text
strings that can be found in this column:
@table @code
@item Distinct
@strong{MySQL} will not continue searching for more rows for the current row
combination after it has found the first matching row.
@item Not exists
@strong{MySQL} was able to do a @code{LEFT JOIN} optimization on the
query and will not examine more rows in this table for a row combination
@ -20779,9 +20834,28 @@ The biggest differences between the ANSI SQL and @strong{MySQL} versions of
@code{GRANT} are:
@itemize @bullet
@item
In @strong{MySQL} privileges are given for an username + hostname combination
and not only for an username.
@item
ANSI SQL doesn't have global or database-level privileges and ANSI SQL
doesn't support all privilege types that @strong{MySQL} supports.
@strong{MySQL} doesn't support the ANSI SQL @code{TRIGGER}, @code{EXECUTE} or
@code{UNDER} privileges.
@item
ANSI SQL privileges are structured in a hierarchal manner. If you remove
an user, all privileges the user has granted are revoked. In
@strong{MySQL} the granted privileges are not automaticly revoked, but
you have to revoke these yourself if needed.
@item
If you in @code{MySQL} have the @code{INSERT} grant on only part of the
columns in a table, you can execute @code{INSERT} statements on the
table; The columns for which you don't have the @code{INSERT} privilege
will set to their default values. ANSI SQL requires you to have the
@code{INSERT} privilege on all columns.
@item
When you drop a table in ANSI SQL, all privileges for the table are revoked.
@ -26092,6 +26166,7 @@ great tool to find out if this is a problem with your query.
* Estimating performance:: Estimating query performance
* SELECT speed:: Speed of @code{SELECT} queries
* Where optimizations:: How MySQL optimizes @code{WHERE} clauses
* DISTINCT optimization::
* LEFT JOIN optimization:: How MySQL optimizes @code{LEFT JOIN}
* LIMIT optimization:: How MySQL optimizes @code{LIMIT}
* Insert speed:: Speed of @code{INSERT} queries
@ -26171,7 +26246,7 @@ time for a large table!
@cindex optimizations
@findex WHERE
@node Where optimizations, LEFT JOIN optimization, SELECT speed, Query Speed
@node Where optimizations, DISTINCT optimization, SELECT speed, Query Speed
@subsection How MySQL optimizes @code{WHERE} clauses
The @code{WHERE} optimizations are put in the @code{SELECT} part here because
@ -26244,18 +26319,14 @@ possibilities. If all columns in @code{ORDER BY} and in @code{GROUP
BY} come from the same table, then this table is preferred first when
joining.
@item
If there is an @code{ORDER BY} clause and a different @code{GROUP BY} clause,
or if the @code{ORDER BY} or @code{GROUP BY}
contains columns from tables other than the first table in the join
queue, a temporary table is created.
If there is an @code{ORDER BY} clause and a different @code{GROUP BY}
clause, or if the @code{ORDER BY} or @code{GROUP BY} contains columns
from tables other than the first table in the join queue, a temporary
table is created.
@item
If you use @code{SQL_SMALL_RESULT}, @strong{MySQL} will use an in-memory
temporary table.
@item
As @code{DISTINCT} is converted to a @code{GROUP BY} on all columns,
@code{DISTINCT} combined with @code{ORDER BY} will in many cases also need
a temporary table.
@item
Each table index is queried and the best index that spans fewer than 30% of
the rows is used. If no such index can be found, a quick table scan is used.
@item
@ -26298,9 +26369,32 @@ mysql> SELECT ... FROM tbl_name ORDER BY key_part1,key_part2,...
mysql> SELECT ... FROM tbl_name ORDER BY key_part1 DESC,key_part2 DESC,...
@end example
@findex DISTINCT
@cindex optimizing, DISTINCT
@node DISTINCT optimization, LEFT JOIN optimization, Where optimizations, Query Speed
@subsection How MySQL optimizes @code{DISTINCT}
@code{DISTINCT} is converted to a @code{GROUP BY} on all columns,
@code{DISTINCT} combined with @code{ORDER BY} will in many cases also
need a temporary table.
When combining @code{LIMIT #} with @code{DISTINCT}, @strong{MySQL} will stop
as soon as it finds @code{#} unique rows.
If you don't use columns from all used tables, @strong{MySQL} will stop
the scanning of the not used tables as soon as it has found the first match.
@example
SELECT DISTINCT t1.a FROM t1,t2 where t1.a=t2.a;
@end example
In the case, assuming t1 is used before t2 (check with @code{EXPLAIN}), then
@strong{MySQL} will stop reading from t2 (for that particular row in t1)
when the first row in t2 is found.
@findex LEFT JOIN
@cindex optimizing, LEFT JOIN
@node LEFT JOIN optimization, LIMIT optimization, Where optimizations, Query Speed
@node LEFT JOIN optimization, LIMIT optimization, DISTINCT optimization, Query Speed
@subsection How MySQL optimizes @code{LEFT JOIN} and @code{RIGHT JOIN}
@code{A LEFT JOIN B} is in @strong{MySQL} implemented as follows:
@ -31397,6 +31491,10 @@ Load the privilege tables with: @code{mysqladmin -h hostname
flush-privileges} or with the SQL command @code{FLUSH PRIVILEGES}.
@end enumerate
Note that after you started @code{mysqld} with @code{--skip-grant-tables},
any usage of @code{GRANT} commands will give you an @code{Unknown command}
error until you have executed @code{FLUSH PRIVILEGES}.
@cindex files, permissions
@cindex error mesaages, can't find file
@cindex files, not found message
@ -37760,6 +37858,16 @@ though, so 3.23 is not released as a stable version yet.
@appendixsubsec Changes in release 3.23.26
@itemize @bullet
@item
Added optimization of queries where @code{DISTINCT} is only used on columns
from some of the tables.
@item
Allow floating point numbers where there are no sign after the exponent
(like 1e1).
@item
@code{SHOW GRANTS} didn't always show all column grants.
@item
Added @code{--default-extra-file=#} to all @strong{MySQL} clients.
@item
Automatic repair of @code{MyISAM} tables.
@item
Columns referenced in @code{INSERT} are are now properly initialized.

14
extra/my_print_defaults.c
View file

@ -32,6 +32,8 @@ static struct option long_options[] =
{
{"config-file", required_argument, 0, 'c'},
{"defaults-file", required_argument, 0, 'c'},
{"defaults-extra-file", required_argument, 0, 'e'},
{"extra-file", required_argument, 0, 'e'},
{"no-defaults", no_argument, 0, 'd'},
{"help", no_argument, 0, '?'},
{"version", no_argument, 0, 'V'},
@ -40,7 +42,7 @@ static struct option long_options[] =
static void usage(my_bool version)
{
printf("%s Ver 1.1 for %s at %s\n",my_progname,SYSTEM_TYPE,
printf("%s Ver 1.2 for %s at %s\n",my_progname,SYSTEM_TYPE,
MACHINE_TYPE);
if (version)
return;
@ -50,6 +52,9 @@ static void usage(my_bool version)
printf("\n\
-c, --config-file=#, --defaults-file=#\n\
The config file to use (default '%s')\n\
-e, --extra-file=#, --defaults-extra-file=#\n\
Read this file after the global /etc config file and\n\
before the config file in the users home directory.\n\
--no-defaults Return an empty string (useful for scripts)\n\
-?, --help Display this help message and exit.\n\
-V, --version Output version information and exit.\n",
@ -61,13 +66,16 @@ static int get_options(int *argc,char ***argv)
{
int c,option_index;
while ((c=getopt_long(*argc,*argv,"c:V?I",
while ((c=getopt_long(*argc,*argv,"c:e:V?I",
long_options, &option_index)) != EOF)
{
switch (c) {
case 'c':
config_file=optarg;
break;
case 'e':
defaults_extra_file=optarg; /* Used by the load_defaults */
break;
case 'n':
exit(0);
case 'I':
@ -102,7 +110,7 @@ int main(int argc, char **argv)
if (get_options(&argc,&argv))
exit(1);
if (!(load_default_groups=(char**) my_malloc((argc+2)*sizeof(char*),
MYF(MY_WME))))
MYF(MY_WME))))
exit(1);
for (count=0; *argv ; argv++,count++)

1
include/my_sys.h
View file

@ -206,6 +206,7 @@ extern my_bool NEAR my_disable_locking,NEAR my_disable_async_io,
NEAR my_disable_flush_key_blocks;
extern char wild_many,wild_one,wild_prefix;
extern const char *charsets_dir;
extern char *defaults_extra_file;
typedef struct wild_file_pack /* Struct to hold info when selecting files */
{

48
mysys/default.c
View file

@ -29,8 +29,9 @@
** The following arguments are handled automaticly; If used, they must be
** first argument on the command line!
** --no-defaults ; no options are read.
** --print-defaults ; Print the modified command line and exit
** --defaults-file=full-path-to-default-file ; Only this file will be read.
** --defaults-extra-file=full-path-to-default-file ; Read this file before ~/
** --print-defaults ; Print the modified command line and exit
****************************************************************************/
#undef SAFEMALLOC /* safe_malloc is not yet initailized */
@ -39,6 +40,8 @@
#include "m_string.h"
#include "m_ctype.h"
char *defaults_extra_file=0;
/* Which directories are searched for options (and in which order) */
const char *default_directories[]= {
@ -50,6 +53,7 @@ const char *default_directories[]= {
#ifdef DATADIR
DATADIR,
#endif
"", /* Place for defaults_extra_dir */
#ifndef __WIN__
"~/",
#endif
@ -71,9 +75,10 @@ void load_defaults(const char *conf_file, const char **groups,
int *argc, char ***argv)
{
DYNAMIC_ARRAY args;
const char **dirs, *extra_default_file;
const char **dirs, *forced_default_file;
TYPELIB group;
my_bool found_print_defaults=0;
uint args_used=0;
MEM_ROOT alloc;
char *ptr,**res;
DBUG_ENTER("load_defaults");
@ -97,9 +102,20 @@ void load_defaults(const char *conf_file, const char **groups,
}
/* Check if we want to force the use a specific default file */
extra_default_file=0;
if (*argc >= 2 && is_prefix(argv[0][1],"--defaults-file="))
extra_default_file=strchr(argv[0][1],'=')+1;
forced_default_file=0;
if (*argc >= 2)
{
if (is_prefix(argv[0][1],"--defaults-file="))
{
forced_default_file=strchr(argv[0][1],'=')+1;
args_used++;
}
else if (is_prefix(argv[0][1],"--defaults-extra-file="))
{
defaults_extra_file=strchr(argv[0][1],'=')+1;
args_used++;
}
}
group.count=0;
group.name= "defaults";
@ -109,9 +125,9 @@ void load_defaults(const char *conf_file, const char **groups,
if (init_dynamic_array(&args, sizeof(char*),*argc, 32))
goto err;
if (extra_default_file)
if (forced_default_file)
{
if (search_default_file(&args, &alloc, "", extra_default_file, "",
if (search_default_file(&args, &alloc, "", forced_default_file, "",
&group))
goto err;
}
@ -132,8 +148,14 @@ void load_defaults(const char *conf_file, const char **groups,
#endif
for (dirs=default_directories ; *dirs; dirs++)
{
if (search_default_file(&args, &alloc, *dirs, conf_file, default_ext,
&group))
int error;
if (**dirs)
error=search_default_file(&args, &alloc, *dirs, conf_file,
default_ext, &group);
else if (defaults_extra_file)
error=search_default_file(&args, &alloc, NullS, defaults_extra_file,
default_ext, &group);
if (error)
goto err;
}
}
@ -145,11 +167,9 @@ void load_defaults(const char *conf_file, const char **groups,
/* copy name + found arguments + command line arguments to new array */
res[0]=argv[0][0];
memcpy((gptr) (res+1), args.buffer, args.elements*sizeof(char*));
if (extra_default_file)
{
--*argc; /* Skipp --defaults-file */
++*argv;
}
/* Skipp --defaults-file and --defaults-extra-file */
(*argc)-= args_used;
(*argv)+= args_used;
/* Check if we wan't to see the new argument list */
if (*argc >= 2 && !strcmp(argv[0][1],"--print-defaults"))

10
sql/sql_acl.cc
View file

@ -2004,6 +2004,8 @@ bool check_grant(THD *thd, uint want_access, TABLE_LIST *tables,
want_access &= ~table->grant.privilege;
goto err; // No grants
}
if (show_table)
continue; // We have some priv on this
table->grant.grant_table=grant_table; // Remember for column test
table->grant.version=grant_version;
@ -2013,8 +2015,6 @@ bool check_grant(THD *thd, uint want_access, TABLE_LIST *tables,
if (!(~table->grant.privilege & want_access))
continue;
if (show_table && table->grant.privilege)
continue; // Test from show tables
if (want_access & ~(grant_table->cols | table->grant.privilege))
{
@ -2457,18 +2457,18 @@ int mysql_show_grants(THD *thd,LEX_USER *lex_user)
!strcmp(lex_user->host.str,host))
{
want_access=grant_table->privs;
if (want_access)
if ((want_access | grant_table->cols) != 0)
{
String global(buff,sizeof(buff));
global.length(0);
global.append("GRANT ",6);
if (test_all_bits(want_access,(TABLE_ACLS & ~GRANT_ACL)))
if (test_all_bits(grant_table->privs,(TABLE_ACLS & ~GRANT_ACL)))
global.append("ALL PRIVILEGES",14);
else
{
int found=0;
uint j,test_access= want_access & ~GRANT_ACL;
uint j,test_access= (want_access | grant_table->cols) & ~GRANT_ACL;
for (counter=0, j = SELECT_ACL;j <= TABLE_ACLS; counter++,j <<= 1)
{

89
sql/sql_select.cc
View file

@ -136,7 +136,8 @@ static void copy_sum_funcs(Item_sum **func_ptr);
static bool add_ref_to_table_cond(THD *thd, JOIN_TAB *join_tab);
static void init_sum_functions(Item_sum **func);
static bool update_sum_func(Item_sum **func);
static void select_describe(JOIN *join, bool need_tmp_table, bool need_order);
static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
bool distinct);
static void describe_info(const char *info);
/*****************************************************************************
@ -171,6 +172,7 @@ mysql_select(THD *thd,TABLE_LIST *tables,List<Item> &fields,COND *conds,
no_order=0;
bzero((char*) &keyuse,sizeof(keyuse));
thd->proc_info="init";
thd->used_tables=0; // Updated by setup_fields
if (setup_fields(thd,tables,fields,1,&all_fields) ||
setup_conds(thd,tables,&conds) ||
@ -261,7 +263,7 @@ mysql_select(THD *thd,TABLE_LIST *tables,List<Item> &fields,COND *conds,
join.join_tab=0;
join.tmp_table_param.copy_field=0;
join.sum_funcs=0;
join.send_records=0L;
join.send_records=join.found_records=0;
join.tmp_table_param.end_write_records= HA_POS_ERROR;
join.first_record=join.sort_and_group=0;
join.select_options=select_options;
@ -506,7 +508,8 @@ mysql_select(THD *thd,TABLE_LIST *tables,List<Item> &fields,COND *conds,
order=0;
select_describe(&join,need_tmp,
(order != 0 &&
(!need_tmp || order != group || simple_group)));
(!need_tmp || order != group || simple_group)),
select_distinct);
error=0;
goto err;
}
@ -557,6 +560,26 @@ mysql_select(THD *thd,TABLE_LIST *tables,List<Item> &fields,COND *conds,
order=0;
}
}
/*
Optimize distinct when used on some of the tables
SELECT DISTINCT t1.a FROM t1,t2 WHERE t1.b=t2.b
In this case we can stop scanning t2 when we have found one t1.a
*/
if (tmp_table->distinct)
{
table_map used_tables= thd->used_tables;
JOIN_TAB *join_tab=join.join_tab+join.tables-1;
do
{
if (used_tables & join_tab->table->map)
break;
join_tab->not_used_in_distinct=1;
} while (join_tab-- != join.join_tab);
}
/* Copy data to the temporary table */
thd->proc_info="Copying to tmp table";
if (do_select(&join,(List<Item> *) 0,tmp_table,0))
goto err; /* purecov: inspected */
@ -2122,7 +2145,7 @@ make_simple_join(JOIN *join,TABLE *tmp_table)
join->tmp_table_param.copy_field=0;
join->first_record=join->sort_and_group=0;
join->sum_funcs=0;
join->send_records=0L;
join->send_records=(ha_rows) 0;
join->group=0;
join_tab->cache.buff=0; /* No cacheing */
@ -2130,15 +2153,16 @@ make_simple_join(JOIN *join,TABLE *tmp_table)
join_tab->select=0;
join_tab->select_cond=0;
join_tab->quick=0;
bzero((char*) &join_tab->read_record,sizeof(join_tab->read_record));
join_tab->type= JT_ALL; /* Map through all records */
join_tab->keys= (uint) ~0; /* test everything in quick */
join_tab->info=0;
join_tab->on_expr=0;
join_tab->ref.key = -1;
join_tab->not_used_in_distinct=0;
join_tab->read_first_record= join_init_read_record;
bzero((char*) &join_tab->read_record,sizeof(join_tab->read_record));
tmp_table->status=0;
tmp_table->null_row=0;
join_tab->read_first_record= join_init_read_record;
return FALSE;
}
@ -3256,7 +3280,6 @@ create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
if (item->with_sum_func && type != Item::SUM_FUNC_ITEM ||
item->const_item())
continue;
if (type == Item::SUM_FUNC_ITEM && !group && !save_sum_fields)
{ /* Can't calc group yet */
((Item_sum*) item)->result_field=0;
@ -3913,7 +3936,9 @@ sub_select(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
if (!(error=(*join_tab->read_first_record)(join_tab)))
{
bool not_exists_optimize=join_tab->table->reginfo.not_exists_optimize;
bool not_exists_optimize= join_tab->table->reginfo.not_exists_optimize;
bool not_used_in_distinct=join_tab->not_used_in_distinct;
ha_rows found_records=join->found_records;
READ_RECORD *info= &join_tab->read_record;
do
@ -3932,6 +3957,8 @@ sub_select(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
{
if ((error=(*next_select)(join,join_tab+1,0)) < 0)
return error;
if (not_used_in_distinct && found_records != join->found_records)
return 0;
}
}
} while (!(error=info->read_record(info)));
@ -4545,23 +4572,21 @@ end_write(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
}
if (!join->having || join->having->val_int())
{
join->found_records++;
if ((error=table->file->write_row(table->record[0])))
{
if (error != HA_ERR_FOUND_DUPP_KEY &&
error != HA_ERR_FOUND_DUPP_UNIQUE)
{
if (create_myisam_from_heap(table, &join->tmp_table_param, error,1))
DBUG_RETURN(1); // Not a table_is_full error
table->uniques=0; // To ensure rows are the same
}
}
else
{
if (error == HA_ERR_FOUND_DUPP_KEY ||
error == HA_ERR_FOUND_DUPP_UNIQUE)
goto end;
if (create_myisam_from_heap(table, &join->tmp_table_param, error,1))
DBUG_RETURN(1); // Not a table_is_full error
table->uniques=0; // To ensure rows are the same
if (++join->send_records >= join->tmp_table_param.end_write_records)
DBUG_RETURN(-3);
}
}
}
end:
DBUG_RETURN(0);
}
@ -4585,6 +4610,7 @@ end_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
DBUG_RETURN(-2); /* purecov: inspected */
}
join->found_records++;
copy_fields(&join->tmp_table_param); // Groups are copied twice.
/* Make a key of group index */
for (group=table->group ; group ; group=group->next)
@ -6335,12 +6361,13 @@ static bool add_ref_to_table_cond(THD *thd, JOIN_TAB *join_tab)
** Send a description about what how the select will be done to stdout
****************************************************************************/
static void select_describe(JOIN *join, bool need_tmp_table, bool need_order)
static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
bool distinct)
{
DBUG_ENTER("select_describe");
List<Item> field_list;
Item *item;
THD *thd=join->thd;
DBUG_ENTER("select_describe");
field_list.push_back(new Item_empty_string("table",NAME_LEN));
field_list.push_back(new Item_empty_string("type",10));
@ -6356,11 +6383,12 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order)
item->maybe_null=1;
field_list.push_back(new Item_real("rows",0.0,0,10));
field_list.push_back(new Item_empty_string("Extra",255));
if (send_fields(join->thd,field_list,1))
if (send_fields(thd,field_list,1))
return; /* purecov: inspected */
char buff[512],*buff_ptr;
String tmp(buff,sizeof(buff)),*packet= &join->thd->packet;
String tmp(buff,sizeof(buff)),*packet= &thd->packet;
table_map used_tables=0;
for (uint i=0 ; i < join->tables ; i++)
{
JOIN_TAB *tab=join->join_tab+i;
@ -6473,11 +6501,22 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order)
}
buff_ptr=strmov(buff_ptr,"Using filesort");
}
if (distinct & test_all_bits(used_tables,thd->used_tables))
{
if (buff != buff_ptr)
{
buff_ptr[0]=';' ; buff_ptr[1]=' '; buff_ptr+=2;
}
buff_ptr=strmov(buff_ptr,"Distinct");
}
net_store_data(packet,buff,(uint) (buff_ptr - buff));
if (my_net_write(&join->thd->net,(char*) packet->ptr(),packet->length()))
if (my_net_write(&thd->net,(char*) packet->ptr(),packet->length()))
DBUG_VOID_RETURN; /* purecov: inspected */
// For next iteration
used_tables|=table->map;
}
send_eof(&join->thd->net);
send_eof(&thd->net);
DBUG_VOID_RETURN;
}

48
sql/sql_select.h
View file

@ -79,36 +79,36 @@ class JOIN;
typedef struct st_join_table {
TABLE *table;
int (*read_first_record)(struct st_join_table *tab);
int (*next_select)(JOIN *,struct st_join_table *,bool);
bool cached_eq_ref_table,eq_ref_table;
READ_RECORD read_record;
uint keys; /* all keys with can be used */
key_map const_keys; /* Keys with constant part */
key_map checked_keys; /* Keys checked in find_best */
key_map needed_reg;
ha_rows records,found_records,read_time;
table_map dependent,key_dependent;
uint use_quick,index;
uint status; // Save status for cache
enum join_type type;
JOIN_CACHE cache;
KEYUSE *keyuse; /* pointer to first used key */
SQL_SELECT *select;
COND *select_cond;
QUICK_SELECT *quick;
Item *on_expr;
uint used_fields,used_fieldlength,used_blobs;
const char *info;
int (*read_first_record)(struct st_join_table *tab);
int (*next_select)(JOIN *,struct st_join_table *,bool);
READ_RECORD read_record;
double worst_seeks;
key_map const_keys; /* Keys with constant part */
key_map checked_keys; /* Keys checked in find_best */
key_map needed_reg;
ha_rows records,found_records,read_time;
table_map dependent,key_dependent;
uint keys; /* all keys with can be used */
uint use_quick,index;
uint status; // Save status for cache
uint used_fields,used_fieldlength,used_blobs;
enum join_type type;
bool cached_eq_ref_table,eq_ref_table,not_used_in_distinct;
TABLE_REF ref;
JOIN_CACHE cache;
} JOIN_TAB;
typedef struct st_position { /* Used in find_best */
double records_read;
JOIN_TAB *table;
KEYUSE *key;
double records_read;
} POSITION;
@ -116,16 +116,16 @@ typedef struct st_position { /* Used in find_best */
class TMP_TABLE_PARAM {
public:
List<Item> copy_funcs;
Copy_field *copy_field;
byte *group_buff;
Item_result_field **funcs;
MI_COLUMNDEF *recinfo,*start_recinfo;
KEY *keyinfo;
ha_rows end_write_records;
uint copy_field_count,field_count,sum_func_count,func_count;
uint group_parts,group_length;
uint quick_group;
Copy_field *copy_field;
byte *group_buff;
ha_rows end_write_records;
Item_result_field **funcs;
List<Item> copy_funcs;
MI_COLUMNDEF *recinfo,*start_recinfo;
KEY *keyinfo;
TMP_TABLE_PARAM() :group_parts(0),group_length(0),copy_field(0) {}
~TMP_TABLE_PARAM()
@ -148,7 +148,7 @@ class JOIN {
uint send_group_parts;
bool sort_and_group,first_record,full_join,group, no_field_update;
table_map const_table_map;
ha_rows send_records;
ha_rows send_records,found_records;
POSITION positions[MAX_TABLES+1],best_positions[MAX_TABLES+1];
double best_read;
List<Item> *fields;