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Commit ca0ba8e0 authored by serg@serg.mysql.com's avatar serg@serg.mysql.com
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Docs/manual.texi
View file @ ca0ba8e0
......@@ -409,6 +409,7 @@ MySQL Language Reference
* LOCK TABLES:: @code{LOCK TABLES/UNLOCK TABLES} syntax
* SET OPTION:: @code{SET OPTION} syntax
* GRANT:: @code{GRANT} and @code{REVOKE} syntax
* HANDLER:: @code{HANDLER} syntax
* CREATE INDEX:: @code{CREATE INDEX} syntax
* DROP INDEX:: @code{DROP INDEX} syntax
* Comments:: Comment syntax
......@@ -13483,6 +13484,7 @@ to restart @code{mysqld} with @code{--skip-grant-tables} to run
* SET OPTION:: @code{SET OPTION} syntax
* SET TRANSACTION:: @code{SET TRANSACTION} syntax
* GRANT:: @code{GRANT} and @code{REVOKE} syntax
* HANDLER:: @code{HANDLER} syntax
* CREATE INDEX:: @code{CREATE INDEX} syntax
* DROP INDEX:: @code{DROP INDEX} syntax
* Comments:: Comment syntax
......@@ -22396,7 +22398,7 @@ You can set the default isolation level for @code{mysqld} with
@findex GRANT
@findex REVOKE
@node GRANT, CREATE INDEX, SET TRANSACTION, Reference
@node GRANT, HANDLER, SET TRANSACTION, Reference
@section @code{GRANT} and @code{REVOKE} Syntax
@example
......@@ -22624,11 +22626,52 @@ dropped only with explicit @code{REVOKE} commands or by manipulating the
@strong{MySQL} grant tables.
@end itemize
@findex HANDLER
@node HANDLER, CREATE INDEX, GRANT, Reference
@section @code{HANDLER} Syntax
@example
HANDLER table OPEN [ AS alias ]
HANDLER table READ index @{ = | >= | <= | < @} (value1, value2, ... ) [ WHERE ... ] [LIMIT ... ]
HANDLER table READ index @{ FIRST | NEXT | PREV | LAST @} [ WHERE ... ] [LIMIT ... ]
HANDLER table READ @{ FIRST | NEXT @} [ WHERE ... ] [LIMIT ... ]
HANDLER table CLOSE
@end example
The @code{HANDLER} statement provides direct access to @strong{MySQL} table
interface, bypassing SQL optimizer. Thus, it is faster then SELECT.
The first form of @code{HANDLER} statement opens a table, making
in accessible via the following @code{HANDLER ... READ} routines.
The second form fetches one (or, specified by @code{LIMIT} clause) row
where the index specified complies to the condition and @code{WHERE}
condition is met. If the index consists of several parts (spans over
several columns) the values are specified in comma-separated list,
providing values only for few first columns is possible.
The third form fetches one (or, specified by @code{LIMIT} clause) row
from the table in index order, matching @code{WHERE} condition.
The fourth form (without index specification) fetches one (or, specified
by @code{LIMIT} clause) row from the table in natural row order (as stored
in data file) matching @code{WHERE} condition. It is faster than
@code{HANDLER table READ index} when full table scan is desired.
The last form closes the table, opened with @code{HANDLER ... OPEN}.
@code{HANDLER} is somewhat low-level statement, for example it does not
provide consistency. That is @code{HANDLER ... OPEN} does @strong{not}
takes a snapshot of the table, and does @strong{not} locks the table. The
above means, that after @code{HANDLER ... OPEN} table data can be
modified (by this or other thread) and these modifications may appear only
partially in @code{HANDLER ... NEXT} or @code{HANDLER ... PREV} scans.
@cindex indexes
@cindex indexes, multi-part
@cindex multi-part index
@findex CREATE INDEX
@node CREATE INDEX, DROP INDEX, GRANT, Reference
@node CREATE INDEX, DROP INDEX, HANDLER, Reference
@section @code{CREATE INDEX} Syntax
@example
mysql-test/t/handler.test
View file @ ca0ba8e0
......@@ -5,8 +5,8 @@
drop table if exists t1;
create table t1 (a int, b char(10), key a(a), key b(a,b));
insert into t1 values
(14,"aaa"),(15,"bbb"),(16,"ccc"),(16,"xxx"),
(17,"ddd"),(18,"eee"),(19,"fff"),(19,"yyy"),
(14,"aaa"),(15,"bbb"),(16,"ccc"),(16,"xxx"),
(20,"ggg"),(21,"hhh"),(22,"iii");
handler t1 open as t2;
handler t2 read a first;
......@@ -50,7 +50,16 @@ handler t2 read a next limit 3;
handler t2 read a prev limit 10;
handler t2 read a>=(16) limit 4;
handler t2 read a>=(16) limit 2,2;
handler t2 read a last limit 3;
handler t2 read a=(19);
handler t2 read a=(19) where b="yyy";
handler t2 read first;
handler t2 read next;
handler t2 read next;
handler t2 read last;
handler t2 close;
drop table if exists t1;
sql/mysql_priv.h
View file @ ca0ba8e0
......@@ -384,8 +384,8 @@ int mysqld_show(THD *thd, const char *wild, show_var_st *variables);
/* sql_handler.cc */
int mysql_ha_open(THD *thd, TABLE_LIST *tables);
int mysql_ha_close(THD *thd, TABLE_LIST *tables);
int mysql_ha_read(THD *, TABLE_LIST *,enum enum_ha_read_modes,
char *,List<Item> *,enum ha_rkey_function,ha_rows,ha_rows);
int mysql_ha_read(THD *, TABLE_LIST *,enum enum_ha_read_modes,char *,
List<Item> *,enum ha_rkey_function,Item *,ha_rows,ha_rows);
/* sql_base.cc */
void set_item_name(Item *item,char *pos,uint length);
......
sql/sql_base.cc
View file @ ca0ba8e0
......@@ -407,7 +407,7 @@ void close_thread_tables(THD *thd, bool locked)
{
DBUG_ENTER("close_thread_tables");
if (thd->locked_tables || thd->manual_open)
if (thd->locked_tables)
DBUG_VOID_RETURN; // LOCK TABLES in use
TABLE *table,*next;
......
sql/sql_class.cc
View file @ ca0ba8e0
......@@ -76,7 +76,7 @@ static void free_var(user_var_entry *entry)
****************************************************************************/
THD::THD():user_time(0),fatal_error(0),last_insert_id_used(0),
insert_id_used(0),in_lock_tables(0),manual_open(0),
insert_id_used(0),in_lock_tables(0),
global_read_lock(0),bootstrap(0)
{
host=user=priv_user=db=query=ip=0;
......@@ -85,7 +85,8 @@ THD::THD():user_time(0),fatal_error(0),last_insert_id_used(0),
query_length=col_access=0;
query_error=0;
next_insert_id=last_insert_id=0;
open_tables=temporary_tables=0;
open_tables=temporary_tables=handler_tables=0;
handler_items=0;
tmp_table=0;
lock=locked_tables=0;
used_tables=0;
......@@ -158,10 +159,14 @@ THD::~THD()
net_end(&net);
}
ha_rollback(this);
if (locked_tables || manual_open)
if (locked_tables)
{
lock=locked_tables; locked_tables=0;
manual_open=0;
close_thread_tables(this);
}
if (handler_tables)
{
open_tables=handler_tables; handler_tables=0;
close_thread_tables(this);
}
close_temporary_tables(this);
......
sql/sql_class.h
View file @ ca0ba8e0
......@@ -231,7 +231,7 @@ public:
const char *proc_info;
uint client_capabilities,max_packet_length;
uint master_access,db_access;
TABLE *open_tables,*temporary_tables;
TABLE *open_tables,*temporary_tables, *handler_tables;
MYSQL_LOCK *lock,*locked_tables;
ULL *ull;
struct st_my_thread_var *mysys_var;
......@@ -253,7 +253,7 @@ public:
#ifdef HAVE_GEMINI_DB
struct st_gemini gemini;
#endif
Item *free_list;
Item *free_list, *handler_items;
CONVERT *convert_set;
Field *dupp_field;
#ifndef __WIN__
......@@ -278,7 +278,7 @@ public:
bool slave_thread;
bool set_query_id,locked,count_cuted_fields,some_tables_deleted;
bool no_errors, allow_sum_func, password, fatal_error;
bool query_start_used,last_insert_id_used,insert_id_used,manual_open;
bool query_start_used,last_insert_id_used,insert_id_used;
bool system_thread,in_lock_tables,global_read_lock;
bool query_error, bootstrap;
bool volatile killed;
......
sql/sql_handler.cc
View file @ ca0ba8e0
......@@ -17,23 +17,53 @@
/* HANDLER ... commands - direct access to ISAM */
#include <assert.h>
#include "mysql_priv.h"
#include "sql_select.h"
/* TODO:
HANDLER blabla OPEN [ AS foobar ] [ (column-list) ]
the most natural (easiest, fastest) way to do it is to
compute List<Item> field_list not in mysql_ha_read
but in mysql_ha_open, and then store it in TABLE structure.
The problem here is that mysql_parse calls free_item to free all the
items allocated at the end of every query. The workaround would to
keep two item lists per THD - normal free_list and handler_items.
The second is to be freeed only on thread end. mysql_ha_open should
then do { handler_items=concat(handler_items, free_list); free_list=0; }
But !!! do_cammand calls free_root at the end of every query and frees up
all the sql_alloc'ed memory. It's harder to work around...
*/
#define HANDLER_TABLES_HACK(thd) { \
TABLE *tmp=thd->open_tables; \
thd->open_tables=thd->handler_tables; \
thd->handler_tables=tmp; }
static TABLE *find_table_by_name(THD *thd, char *db, char *table_name);
int mysql_ha_open(THD *thd, TABLE_LIST *tables)
{
HANDLER_TABLES_HACK(thd);
int err=open_tables(thd,tables);
if (!err)
{
thd->manual_open=1;
HANDLER_TABLES_HACK(thd);
if (err)
return -1;
send_ok(&thd->net);
}
return 0;
}
int mysql_ha_close(THD *thd, TABLE_LIST *tables)
{
/* Perhaps, we should close table here.
But it's not easy - *tables is a single-linked list, designed
to be closed at all once.
So, why bother ? All the tables will be closed at thread exit.
*/
send_ok(&thd->net);
return 0;
}
......@@ -43,28 +73,31 @@ static enum enum_ha_read_modes rkey_to_rnext[]=
int mysql_ha_read(THD *thd, TABLE_LIST *tables,
enum enum_ha_read_modes mode, char *keyname, List<Item> *key_expr,
enum ha_rkey_function ha_rkey_mode,
enum ha_rkey_function ha_rkey_mode, Item *cond,
ha_rows select_limit,ha_rows offset_limit)
{
int err;
int err, keyno=-1;
TABLE *table=find_table_by_name(thd, tables->db, tables->name);
if (!table)
{
my_printf_error(ER_UNKNOWN_TABLE,ER(ER_UNKNOWN_TABLE),MYF(0),
tables->name,"HANDLER");
// send_error(&thd->net,ER_UNKNOWN_TABLE);
// send_ok(&thd->net);
return -1;
}
tables->table=table;
int keyno=find_type(keyname, &table->keynames, 1+2)-1;
if (keyno<0)
if (cond && cond->fix_fields(thd,tables))
return -1;
if (keyname)
{
if ((keyno=find_type(keyname, &table->keynames, 1+2)-1)<0)
{
my_printf_error(ER_KEY_DOES_NOT_EXITS,ER(ER_KEY_DOES_NOT_EXITS),MYF(0),
keyname,tables->name);
return -1;
}
}
List<Item> list;
list.push_front(new Item_field(NULL,NULL,"*"));
......@@ -75,55 +108,62 @@ int mysql_ha_read(THD *thd, TABLE_LIST *tables,
table->file->index_init(keyno);
if (select_limit == thd->default_select_limit) select_limit=1;
select_limit+=offset_limit;
for (uint num_rows=0; num_rows < select_limit; num_rows++)
send_fields(thd,list,1);
MYSQL_LOCK *lock=mysql_lock_tables(thd,&tables->table,1);
for (uint num_rows=0; num_rows < select_limit; )
{
switch(mode)
{
case RFIRST:
err=table->file->index_first(table->record[0]);
err=keyname ?
table->file->index_first(table->record[0]) :
table->file->rnd_init(1) ||
table->file->rnd_next(table->record[0]);
mode=RNEXT;
break;
case RLAST:
dbug_assert(keyname != 0);
err=table->file->index_last(table->record[0]);
mode=RPREV;
break;
case RNEXT:
err=table->file->index_next(table->record[0]);
err=keyname ?
table->file->index_next(table->record[0]) :
table->file->rnd_next(table->record[0]);
break;
case RPREV:
dbug_assert(keyname != 0);
err=table->file->index_prev(table->record[0]);
break;
case RKEY:
{
dbug_assert(keyname != 0);
KEY *keyinfo=table->key_info+keyno;
uint key_len=0, i;
byte *key, *buf;
KEY_PART_INFO *key_part=keyinfo->key_part;
uint key_len;
byte *key;
if (key_expr->elements > keyinfo->key_parts)
{
my_printf_error(ER_TOO_MANY_KEY_PARTS,ER(ER_TOO_MANY_KEY_PARTS),
MYF(0),keyinfo->key_parts);
return -1;
goto err;
}
for (i=0; i < key_expr->elements; i++)
key_len+=keyinfo->key_part[i].store_length;
if (!(key=sql_calloc(ALIGN_SIZE(key_len))))
List_iterator<Item> it_ke(*key_expr);
Item *item;
for (key_len=0 ; (item=it_ke++) ; key_part++)
{
send_error(&thd->net,ER_OUTOFMEMORY);
return -1;
item->save_in_field(key_part->field);
key_len+=key_part->store_length;
}
List_iterator<Item> it_ke(*key_expr);
for (i=0, buf=key; i < key_expr->elements; i++)
if (!(key=sql_calloc(ALIGN_SIZE(key_len))))
{
uint maybe_null= test(keyinfo->key_part[i].null_bit);
store_key_item ski=store_key_item(keyinfo->key_part[i].field,
(char*)buf+maybe_null,maybe_null ? (char*) buf : 0,
keyinfo->key_part[i].length, it_ke++);
ski.copy();
buf+=keyinfo->key_part[i].store_length;
send_error(&thd->net,ER_OUTOFMEMORY);
goto err;
}
key_copy(key, table, keyno, key_len);
err=table->file->index_read(table->record[0],
key,key_len,ha_rkey_mode);
mode=rkey_to_rnext[(int)ha_rkey_mode];
......@@ -131,19 +171,28 @@ int mysql_ha_read(THD *thd, TABLE_LIST *tables,
}
default:
send_error(&thd->net,ER_ILLEGAL_HA);
return -1;
goto err;
}
if (err && err != HA_ERR_KEY_NOT_FOUND && err != HA_ERR_END_OF_FILE)
if (err)
{
if (err != HA_ERR_KEY_NOT_FOUND && err != HA_ERR_END_OF_FILE)
{
sql_print_error("mysql_ha_read: Got error %d when reading table",
err);
table->file->print_error(err,MYF(0));
return -1;
goto err;
}
goto ok;
}
if (cond)
{
err=err;
if(!cond->val_int())
continue;
}
if (num_rows>=offset_limit)
{
if (num_rows==offset_limit) send_fields(thd,list,1);
if (!err)
{
String *packet = &thd->packet;
......@@ -156,15 +205,21 @@ int mysql_ha_read(THD *thd, TABLE_LIST *tables,
{
packet->free(); // Free used
my_error(ER_OUT_OF_RESOURCES,MYF(0));
return -1;
goto err;
}
}
my_net_write(&thd->net, (char*)packet->ptr(), packet->length());
}
}
num_rows++;
}
ok:
mysql_unlock_tables(thd,lock);
send_eof(&thd->net);
return 0;
err:
mysql_unlock_tables(thd,lock);
return -1;
}
/**************************************************************************
......@@ -184,7 +239,7 @@ static TABLE *find_table_by_name(THD *thd, char *db, char *table_name)
if (!db || ! *db) db="";
dblen=strlen(db);
for (TABLE *table=thd->open_tables; table ; table=table->next)
for (TABLE *table=thd->handler_tables; table ; table=table->next)
{
if (!memcmp(table->table_cache_key, db, dblen) &&
!my_strcasecmp(table->table_name,table_name))
......
sql/sql_parse.cc
View file @ ca0ba8e0
......@@ -2009,8 +2009,8 @@ mysql_execute_command(void)
case SQLCOM_HA_READ:
if (check_db_used(thd,tables) || check_table_access(thd,SELECT_ACL, tables))
goto error;
res = mysql_ha_read(thd, tables, lex->ha_read_mode,
lex->backup_dir, lex->insert_list, lex->ha_rkey_mode,
res = mysql_ha_read(thd, tables, lex->ha_read_mode, lex->backup_dir,
lex->insert_list, lex->ha_rkey_mode, lex->where,
lex->select_limit, lex->offset_limit);
break;
......@@ -2059,7 +2059,7 @@ mysql_execute_command(void)
}
thd->proc_info="query end"; // QQ
if (res < 0)
send_error(&thd->net,thd->killed ? ER_SERVER_SHUTDOWN : 0, 0);
send_error(&thd->net,thd->killed ? ER_SERVER_SHUTDOWN : 0);
error:
DBUG_VOID_RETURN;
......
sql/sql_yacc.yy
View file @ ca0ba8e0
......@@ -535,7 +535,8 @@ bool my_yyoverflow(short **a, YYSTYPE **b,int *yystacksize);
equal optional_braces opt_key_definition key_usage_list2
opt_mi_check_type opt_to mi_check_types normal_join
table_to_table_list table_to_table opt_table_list opt_as
handler_read_function handler_rkey_mode END_OF_INPUT
handler_rkey_function handler_rkey_mode handler_read_or_scan
END_OF_INPUT
%type <NONE>
'-' '+' '*' '/' '%' '(' ')'
......@@ -1904,7 +1905,8 @@ order_dir:
limit_clause:
/* empty */
{
Lex->select_limit= current_thd->default_select_limit;
Lex->select_limit= (Lex->sql_command == SQLCOM_HA_READ) ?
1 : current_thd->default_select_limit;
Lex->offset_limit= 0L;
}
| LIMIT ULONG_NUM
......@@ -2844,7 +2846,7 @@ unlock:
/*
** Table: direct access to ISAM functions
** Handler: direct access to ISAM functions
*/
handler:
......@@ -2860,44 +2862,39 @@ handler:
if (!add_table_to_list($2,0,0))
YYABORT;
}
| HANDLER_SYM table_ident READ_SYM ident handler_read_function limit_clause
| HANDLER_SYM table_ident READ_SYM handler_read_or_scan
{
Lex->sql_command = SQLCOM_HA_READ;
Lex->backup_dir= $4.str;
if (!add_table_to_list($2,0,0))
YYABORT;
}
where_clause limit_clause { }
handler_read_function:
FIRST_SYM
{
Lex->ha_read_mode = RFIRST;
}
| NEXT_SYM
{
Lex->ha_read_mode = RNEXT;
}
| PREV_SYM
{
Lex->ha_read_mode = RPREV;
}
| LAST_SYM
{
Lex->ha_read_mode = RLAST;
}
handler_read_or_scan:
handler_scan_function { Lex->backup_dir= 0; }
| ident handler_rkey_function { Lex->backup_dir= $1.str; }
handler_scan_function:
FIRST_SYM { Lex->ha_read_mode = RFIRST; }
| NEXT_SYM { Lex->ha_read_mode = RNEXT; }
handler_rkey_function:
FIRST_SYM { Lex->ha_read_mode = RFIRST; }
| NEXT_SYM { Lex->ha_read_mode = RNEXT; }
| PREV_SYM { Lex->ha_read_mode = RPREV; }
| LAST_SYM { Lex->ha_read_mode = RLAST; }
| handler_rkey_mode
{
Lex->ha_read_mode = RKEY;
if (!(Lex->insert_list = new List_item))
YYABORT;
}
'(' values ')' { }
} '(' values ')' { }
handler_rkey_mode:
EQ { Lex->ha_rkey_mode=HA_READ_KEY_EXACT; }
| GE { Lex->ha_rkey_mode=HA_READ_KEY_OR_NEXT; }
| LE { Lex->ha_rkey_mode=HA_READ_KEY_OR_PREV; }
| GT_SYM {Lex->ha_rkey_mode=HA_READ_AFTER_KEY; }
| GT_SYM { Lex->ha_rkey_mode=HA_READ_AFTER_KEY; }
| LT { Lex->ha_rkey_mode=HA_READ_BEFORE_KEY; }
/* GRANT / REVOKE */
......
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