Hi Guilhem,
Thanks for the patch and for a detailed explanation in commit comments
about why this fails.
However, it would be good with an "executive summary" in the
non-file-specific part of the commit comments that sums up the issue
and what has been done to fix it. To me it was actually not quite
clear from the commit comments what changes have actually been made.
It kind of "drowned" in the detailed specification of the problem.
IIUC, the basic message is that the described save/restore logic is
not necessary since all engines sets table->status, anyway. I think
this could be said more explicitly.
I also wonder why the reported test case only fails for
join_cache_level=3. Is this because buffers were not filled up when
incremental buffers were used?
I have only minor comments to the actual code (see inline), so patch
is approved.
On 04/ 1/11 11:09 AM, Guilhem Bichot wrote:
> #At file:///home/mysql_src/bzrrepos_new/59651/ based on
revid:roy.lyseng@stripped
>
> 3348 Guilhem Bichot 2011-04-01
> Fix for BUG#11766522 "59651: ASSERTION `TABLE_REF->HAS_RECORD'
FAILED WITH JOIN_CACHE_LEVEL=3":
> during execution, access to last-in-plan tables spoiled
TABLE::status of first tables.
> @ mysql-test/include/join_cache.inc
> test for bug. Without the code fix, join_cache_jcl3 would
hit an assertion failure in join_read_key2.
> @ mysql-test/r/join_cache_jcl1.result
> correct result (32 rows)
> @ mysql-test/r/join_cache_jcl2.result
> correct result (32 rows)
> @ mysql-test/r/join_cache_jcl3.result
> correct result (32 rows)
> @ mysql-test/r/join_cache_jcl4.result
> correct result (32 rows)
> @ mysql-test/r/join_cache_jcl5.result
> correct result (32 rows)
> @ mysql-test/r/join_cache_jcl6.result
> correct result (32 rows)
> @ mysql-test/r/join_cache_jcl7.result
> correct result (32 rows)
> @ mysql-test/r/join_cache_jcl8.result
> correct result (32 rows)
> @ sql/handler.h
> Removing the assignments to table->status
> from ha_innodb.cc, ha_myisam.cc, ha_heap.cc causes test
failures,
> which shows that engines must set table->status.
> So tell this brutal truth, in comments: engines must set
table->status.
I think it should be made more explicit that only comments have been
changed/added in this file.
> All those which I could check, do so (including PBXT).
> Question for reviewers: most of the affected handler functions
> have ha_* non-virtual wrappers (ha_index_next_same(), etc);
> we could, in a follow-up patch:
> - remove the requirement from the engine (don't set
table->status
> in their functions anymore)
> - set table->status in the ha_* wrappers.
> - make STATUS_ * flags invisible to engines
> - change them to an enum, and replace the magic value "0"
> with an enum value.
Sounds like very good ideas to me.
> @ sql/sql_join_cache.cc
> Deleting broken code which caused the bug. It was broken for
two reasons.
> First, it affected JOIN_TABs located _before_ 'join_tab' in
the plan;
> there is no reason why reading rows from 'join_tab' should
affect
> TABLE::status of previous JOIN_TABs.
> Second, the save/restore logic was not recursion-safe; consider:
> int save_x, x; // global variables
> f()
> {
> save_x= x; // save
> f();
> x= save_x; // restore
> }
> the inner call to f() will overwrite the value of save_x,
> in the end x will not get its original value back.
> That is what caused the assertion failure. In the bug's
testcase,
> the last tables of the plan are t7, t8, t6. t7 is doing ref
access,
> t8 and t6 are doing join buffering. During execution,
> at some point, no row is found in t7 so t7's table->status
is set to
> STATUS_NOT_FOUND // because no record found
> | STATUS_NULL_ROW // because NULL-complemented (LEFT JOIN)
> Then we continue into t8: at some point the join buffer of
t8 is full,
> so t8 cannot accumulate more partial records sent by t7, so
> join_records() is called for t8, to generate records (of t8
joined
> with its buffer), in order to be able to later empty t8's
buffer.
> Those records are generated, which backs up t7's table->status
> into t7's tab->status, and changes table->status to 0.
> Generated records are passed to t6. t6's buffer gets full. So
> join_records() is called for t6. Which backs up t7's
table->status
> (0) into t7's tab->status. From then on, things are wrong,
as when
> the two join_records() finally end, t7's table->status is not
> restored to its original value
(STATUS_NOT_FOUND|STATUS_NULL_ROW)
> but to 0 ("save_x" issue above). After that, more rows come
from tables
> before t7, so we have another ref access to t7 i.e. a call
to join_read_key2(),
> which has this code:
> if (cmp_buffer_with_ref(tab->join->thd, table, table_ref) ||
> (table->status& (STATUS_GARBAGE | STATUS_NULL_ROW)))
> {
> ...
> }
> else if (table->status == 0)
> {
> DBUG_ASSERT(table_ref->has_record);
> table_ref->use_count++;
> }
> The "else" branch is expected to be for when:
> - the lookup value is the same as the previous lookup value
(see cmp_buffer_with_ref())
> - the previous lookup did find a record (i.e. table->status==0)
> - in which case there should be a record ready for reusal
> (which is asserted with table_ref->has_record) and a new
lookup can be avoided.
> But in our case, though the lookup value is the same, there
> is no record; if t7's table->status was correct it would still
> have STATUS_NULL_ROW and we wouldn't enter the "else" block.
> Because t7's table->status is wrongly 0, we enter the "else"
> and the assertion fires, because there is no record actually.
>
> This code dates from 2000 at the latest (when code was
imported into bitkeeper).
>
> It is unlikely that this causes a real bug in 5.1 or 5.5
because:
> - those older versions do join buffering only for inner join
> - in an inner join, if the "ref" access finds no rows, we don't
> go into the "next" tables, so have no chance to corrupt
table->status
> of the table doing "ref" access.
> @ sql/sql_select.cc
> unused flag (was never set)
This is no longer the only change.
> @ sql/sql_select.h
> JOIN_TAB::status not needed anymore
> @ sql/structs.h
> Best-effort documentation of STATUS_ flags, to the extent of
what I understood.
> Deleting STATUS_PARENT and STATUS_NOT_READ: they were never
set, and this is sure:
It should be STATUS_NO_PARENT
> Deleting STATUS_NO_RECORD.
I think the above line is misplaced since the below lines is
associated with the previous line. I think you should also explain
why STATUS_NO_RECORD could be deleted.
> I temporarily changed TABLE::status to an enum so that any
> table->status= 8; /* using 8 instead of STATUS_NOT_READ */
> would be caught by the compiler.
>
> modified:
> mysql-test/include/join_cache.inc
> mysql-test/r/join_cache_jcl1.result
> mysql-test/r/join_cache_jcl2.result
> mysql-test/r/join_cache_jcl3.result
> mysql-test/r/join_cache_jcl4.result
> mysql-test/r/join_cache_jcl5.result
> mysql-test/r/join_cache_jcl6.result
> mysql-test/r/join_cache_jcl7.result
> mysql-test/r/join_cache_jcl8.result
> sql/handler.h
> sql/item_cmpfunc.cc
> sql/sql_base.h
> sql/sql_join_cache.cc
> sql/sql_select.cc
> sql/sql_select.h
> sql/structs.h
> sql/table.cc
> === modified file 'mysql-test/include/join_cache.inc'
> --- a/mysql-test/include/join_cache.inc 2010-08-11 13:28:19 +0000
> +++ b/mysql-test/include/join_cache.inc 2011-04-01 09:09:15 +0000
> @@ -1577,3 +1577,72 @@ eval explain $query;
> eval $query;
>
> drop table t1,t2;
> +
> +--echo
> +--echo # Bug#11766522 "59651: ASSERTION `TABLE_REF->HAS_RECORD' FAILED
> +--echo # WITH JOIN_CACHE_LEVEL=3"
> +--echo
> +
> +CREATE TABLE t1 (
> + b varchar(20)
> +) ;
> +INSERT INTO t1 VALUES ('1'),('1');
> +
> +CREATE TABLE t4 (
> + col253 text
> +) ;
> +INSERT INTO t4 VALUES (''),('pf');
> +
> +CREATE TABLE t6 (
> + col282 timestamp
> +) ;
> +INSERT INTO t6 VALUES ('2010-11-07 01:04:45'),('2010-12-13 01:36:32');
> +
> +CREATE TABLE t7 (
> + col319 timestamp NOT NULL,
> + UNIQUE KEY idx263 (col319)
> +) ;
> +# zero rows would do, if there was no const-table optimization
> +insert into t7 values("2000-01-01"),("2000-01-02");
> +
> +CREATE TABLE t3 (
> + col582 char(230) CHARACTER SET utf8 DEFAULT NULL
> +) ;
> +# one single row would do, if there was no const-table optimization
> +INSERT INTO t3 VALUES ('cymej'),('spb');
> +
> +CREATE TABLE t5 (
> + col712 time
> +) ;
> +# zero rows would do, if there was no const-table optimization
> +insert into t5 values(0),(0);
> +
> +CREATE TABLE t8 (
> + col804 char(169),
> + col805 varchar(51)
> +) ;
> +INSERT INTO t8 VALUES ('tmqcb','pwk');
> +
> +CREATE TABLE t2 (
> + col841 varchar(10)
> +) ;
> +# one single row would do, if there was no const-table optimization
> +INSERT INTO t2 VALUES (''),('');
> +
> +# small buffer, to trigger "full buffer" in both caches of t8 and t6
> +set join_buffer_size=1;
> +select @@join_buffer_size;
I think you should explain that buffer size will not be 1, bit lowest
possible, and that a warning is expected.
> +
> +--disable_warnings
> +select 1 from
> +(t1 join t2 join t3)
> +left join t4 on 1
> +left join t5 on 1 like t4.col253
> +left join t6 on t5.col712 is null
> +left join t7 on t1.b<=>t7.col319
> +left join t8 on t3.col582<= 1;
> +--enable_warnings
> +
> +drop table t1,t2,t3,t4,t5,t6,t7,t8;
> +
> +set @@join_buffer_size=default;
>
> === modified file 'mysql-test/r/join_cache_jcl1.result'
> --- a/mysql-test/r/join_cache_jcl1.result 2011-02-17 14:42:21 +0000
> +++ b/mysql-test/r/join_cache_jcl1.result 2011-04-01 09:09:15 +0000
> @@ -2250,5 +2250,91 @@ col_int_key col_datetime
> 0 2000-09-26 07:45:57
> 2 2003-02-11 21:19:41
> drop table t1,t2;
> +
> +# Bug#11766522 "59651: ASSERTION `TABLE_REF->HAS_RECORD' FAILED
> +# WITH JOIN_CACHE_LEVEL=3"
> +
> +CREATE TABLE t1 (
> +b varchar(20)
> +) ;
> +INSERT INTO t1 VALUES ('1'),('1');
> +CREATE TABLE t4 (
> +col253 text
> +) ;
> +INSERT INTO t4 VALUES (''),('pf');
> +CREATE TABLE t6 (
> +col282 timestamp
> +) ;
> +INSERT INTO t6 VALUES ('2010-11-07 01:04:45'),('2010-12-13 01:36:32');
> +CREATE TABLE t7 (
> +col319 timestamp NOT NULL,
> +UNIQUE KEY idx263 (col319)
> +) ;
> +insert into t7 values("2000-01-01"),("2000-01-02");
> +CREATE TABLE t3 (
> +col582 char(230) CHARACTER SET utf8 DEFAULT NULL
> +) ;
> +INSERT INTO t3 VALUES ('cymej'),('spb');
> +CREATE TABLE t5 (
> +col712 time
> +) ;
> +insert into t5 values(0),(0);
> +CREATE TABLE t8 (
> +col804 char(169),
> +col805 varchar(51)
> +) ;
> +INSERT INTO t8 VALUES ('tmqcb','pwk');
> +CREATE TABLE t2 (
> +col841 varchar(10)
> +) ;
> +INSERT INTO t2 VALUES (''),('');
> +set join_buffer_size=1;
> +Warnings:
> +Warning 1292 Truncated incorrect join_buffer_size value: '1'
> +select @@join_buffer_size;
> +@@join_buffer_size
> +128
> +select 1 from
> +(t1 join t2 join t3)
> +left join t4 on 1
> +left join t5 on 1 like t4.col253
> +left join t6 on t5.col712 is null
> +left join t7 on t1.b<=>t7.col319
> +left join t8 on t3.col582<= 1;
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
> +1
This result is a bit "boring" ;-) I suggest using "select count(*)"
instead of "select 1". Also makes it easier to spot differences
between result files.
> +drop table t1,t2,t3,t4,t5,t6,t7,t8;
> +set @@join_buffer_size=default;
> set optimizer_join_cache_level = default;
> set optimizer_switch = default;
>
...
> === modified file 'sql/handler.h'
> --- a/sql/handler.h 2011-01-26 21:12:56 +0000
> +++ b/sql/handler.h 2011-04-01 09:09:15 +0000
> @@ -1799,9 +1799,12 @@ public:
> }
> /**
> @brief
> - Positions an index cursor to the index specified in the handle.
Fetches the
> - row if available. If the key value is null, begin at the first
key of the
> - index.
> + Positions an index cursor to the index specified in the handle
> + ('active_index'). Fetches the row if available. If the key
value is null,
> + begin at the first key of the index.
> + To indicate success (found a record), function returns 0 _and_
> + sets table->status to 0. Otherwise, returns non-zero and sets
> + table->status to STATUS_NOT_FOUND.
I suggest adding a @returns tag here.
> */
> virtual int index_read_map(uchar * buf, const uchar * key,
> key_part_map keypart_map,
> @@ -1813,27 +1816,34 @@ public:
> protected:
> /**
> @brief
> - Positions an index cursor to the index specified in the handle.
Fetches the
> - row if available. If the key value is null, begin at the first
key of the
> - index.
> + Positions an index cursor to the index specified in parameter.
Fetches
> + the row if available. If the key value is null, begin at the
first key of
> + the index.
> + @returns as index_read_map().
At first, the above line was a bit confusing to me. I suggest "@see
index_read_map(), instead"
> */
> virtual int index_read_idx_map(uchar * buf, uint index, const
uchar * key,
> key_part_map keypart_map,
> enum ha_rkey_function find_flag);
> + /// @returns as index_read_map().
> virtual int index_next(uchar * buf)
> { return HA_ERR_WRONG_COMMAND; }
> + /// @returns as index_read_map().
> virtual int index_prev(uchar * buf)
> { return HA_ERR_WRONG_COMMAND; }
> + /// @returns as index_read_map().
> virtual int index_first(uchar * buf)
> { return HA_ERR_WRONG_COMMAND; }
> + /// @returns as index_read_map().
> virtual int index_last(uchar * buf)
> { return HA_ERR_WRONG_COMMAND; }
> public:
> + /// @returns as index_read_map().
> virtual int index_next_same(uchar *buf, const uchar *key, uint
keylen);
> /**
> @brief
> The following functions works like index_read, but it find the
last
> row with the current key value or prefix.
> + @returns as index_read_map().
> */
> virtual int index_read_last_map(uchar * buf, const uchar * key,
> key_part_map keypart_map)
> @@ -1853,7 +1863,9 @@ public:
> { return NULL; }
> virtual int ft_read(uchar *buf) { return HA_ERR_WRONG_COMMAND; }
> protected:
> + /// @returns as index_read_map().
> virtual int rnd_next(uchar *buf)=0;
> + /// @returns as index_read_map().
> virtual int rnd_pos(uchar * buf, uchar *pos)=0;
> public:
> /**
>
> === modified file 'sql/item_cmpfunc.cc'
> --- a/sql/item_cmpfunc.cc 2011-02-08 15:54:12 +0000
> +++ b/sql/item_cmpfunc.cc 2011-04-01 09:09:15 +0000
> @@ -430,7 +430,8 @@ static bool convert_constant_item(THD *t
> */
> bool save_field_value= (field_item->depended_from&&
> (field_item->const_item() ||
> - !(field->table->status&
STATUS_NO_RECORD)));
> + !(field->table->status&
> + (STATUS_GARBAGE | STATUS_NOT_FOUND))));
I think a helper function that returned (STATUS_GARBAGE |
STATUS_NOT_FOUND) would be good so one did not have to remember to
test for both all over the place.
> if (save_field_value)
> orig_field_val= field->val_int();
> if (!(*item)->is_null()&& !(*item)->save_in_field(field, 1))
>
> === modified file 'sql/sql_base.h'
> --- a/sql/sql_base.h 2010-11-23 22:37:59 +0000
> +++ b/sql/sql_base.h 2011-04-01 09:09:15 +0000
> @@ -323,7 +323,7 @@ inline void setup_table_map(TABLE *table
> table->used_fields= 0;
> table->const_table= 0;
> table->null_row= 0;
> - table->status= STATUS_NO_RECORD;
> + table->status= STATUS_GARBAGE | STATUS_NOT_FOUND;
> table->maybe_null= table_list->outer_join;
> TABLE_LIST *embedding= table_list->embedding;
> while (!table->maybe_null&& embedding)
>
> === modified file 'sql/sql_join_cache.cc'
> --- a/sql/sql_join_cache.cc 2010-09-02 07:34:10 +0000
> +++ b/sql/sql_join_cache.cc 2011-04-01 09:09:15 +0000
> @@ -1761,7 +1761,6 @@ enum_nested_loop_state JOIN_CACHE_BNL::j
> {
> uint cnt;
> int error;
> - JOIN_TAB *tab;
> READ_RECORD *info;
> enum_nested_loop_state rc= NESTED_LOOP_OK;
> SQL_SELECT *select= join_tab->cache_select;
> @@ -1788,18 +1787,9 @@ enum_nested_loop_state JOIN_CACHE_BNL::j
> join_tab->select->quick= 0;
> }
>
> - for (tab= join->join_tab; tab != join_tab ; tab++)
> - {
> - tab->status= tab->table->status;
> - tab->table->status= 0;
> - }
> -
> /* Start retrieving all records of the joined table */
> if ((error= join_init_read_record(join_tab)))
> - {
> - rc= error< 0 ? NESTED_LOOP_NO_MORE_ROWS: NESTED_LOOP_ERROR;
> - goto finish;
> - }
> + return error< 0 ? NESTED_LOOP_NO_MORE_ROWS: NESTED_LOOP_ERROR;
>
> info=&join_tab->read_record;
> do
> @@ -1811,8 +1801,7 @@ enum_nested_loop_state JOIN_CACHE_BNL::j
> {
> /* The user has aborted the execution of the query */
> join->thd->send_kill_message();
> - rc= NESTED_LOOP_KILLED;
> - goto finish;
> + return NESTED_LOOP_KILLED;
> }
>
> /*
> @@ -1826,10 +1815,7 @@ enum_nested_loop_state JOIN_CACHE_BNL::j
>
(!select->skip_record(join->thd,&skip_record)&&
> !skip_record));
> if (select&& join->thd->is_error())
> - {
> - rc= NESTED_LOOP_ERROR;
> - goto finish;
> - }
> + return NESTED_LOOP_ERROR;
> if (consider_record)
> {
> /* Prepare to read records from the join buffer */
> @@ -1847,7 +1833,7 @@ enum_nested_loop_state JOIN_CACHE_BNL::j
> get_record();
> rc= generate_full_extensions(get_curr_rec());
> if (rc != NESTED_LOOP_OK&& rc != NESTED_LOOP_NO_MORE_ROWS)
> - goto finish;
> + return rc;
> }
> }
> }
> @@ -1856,9 +1842,6 @@ enum_nested_loop_state JOIN_CACHE_BNL::j
>
> if (error> 0) // Fatal error
> rc= NESTED_LOOP_ERROR;
> -finish:
> - for (tab= join->join_tab; tab != join_tab ; tab++)
> - tab->table->status= tab->status;
> return rc;
> }
>
> @@ -2299,7 +2282,7 @@ enum_nested_loop_state JOIN_CACHE_BKA::j
>
> rc= init_join_matching_records(&seq_funcs, records);
> if (rc != NESTED_LOOP_OK)
> - goto finish;
> + return rc;
>
> while (!(error= file->multi_range_read_next((char **)&rec_ptr)))
> {
> @@ -2307,8 +2290,7 @@ enum_nested_loop_state JOIN_CACHE_BKA::j
> {
> /* The user has aborted the execution of the query */
> join->thd->send_kill_message();
> - rc= NESTED_LOOP_KILLED;
> - goto finish;
> + return NESTED_LOOP_KILLED;
> }
> if (join_tab->keep_current_rowid)
> join_tab->table->file->position(join_tab->table->record[0]);
> @@ -2323,14 +2305,13 @@ enum_nested_loop_state JOIN_CACHE_BKA::j
> get_record_by_pos(rec_ptr);
> rc= generate_full_extensions(rec_ptr);
> if (rc != NESTED_LOOP_OK&& rc != NESTED_LOOP_NO_MORE_ROWS)
> - goto finish;
> + return rc;
> }
> }
>
> if (error> 0&& error != HA_ERR_END_OF_FILE)
> return NESTED_LOOP_ERROR;
> -finish:
> - return end_join_matching_records(rc);
> + return rc;
> }
>
>
> @@ -2375,12 +2356,6 @@ JOIN_CACHE_BKA::init_join_matching_recor
> /* Dynamic range access is never used with BKA */
> DBUG_ASSERT(join_tab->use_quick != 2);
>
> - for (JOIN_TAB *tab =join->join_tab; tab != join_tab ; tab++)
> - {
> - tab->status= tab->table->status;
> - tab->table->status= 0;
> - }
> -
> init_mrr_buff();
>
> /*
> @@ -2398,31 +2373,6 @@ JOIN_CACHE_BKA::init_join_matching_recor
>
>
> /*
> - Finish searching for records that match records from the join buffer
> -
> - SYNOPSIS
> - end_join_matching_records()
> - rc return code passed by the join_matching_records function
> -
> - DESCRIPTION
> - This function perform final actions on searching for all matches for
> - the records from the join buffer and building all full join
extensions
> - of the records with these matches.
> -
> - RETURN
> - return code rc passed to the function as a parameter
> -*/
> -
> -enum_nested_loop_state
> -JOIN_CACHE_BKA::end_join_matching_records(enum_nested_loop_state rc)
> -{
> - for (JOIN_TAB *tab=join->join_tab; tab != join_tab ; tab++)
> - tab->table->status= tab->status;
> - return rc;
> -}
> -
> -
> -/*
> Get the key built over the next record from BKA join buffer
>
> SYNOPSIS
> @@ -3192,7 +3142,7 @@ JOIN_CACHE_BKA_UNIQUE::join_matching_rec
>
> rc= init_join_matching_records(&seq_funcs, key_entries);
> if (rc != NESTED_LOOP_OK)
> - goto finish;
> + return rc;
>
> while (!(error= file->multi_range_read_next((char
**)&key_chain_ptr)))
> {
> @@ -3227,8 +3177,7 @@ JOIN_CACHE_BKA_UNIQUE::join_matching_rec
> {
> /* The user has aborted the execution of the query */
> join->thd->send_kill_message();
> - rc= NESTED_LOOP_KILLED;
> - goto finish;
> + return NESTED_LOOP_KILLED;
> }
> /*
> If only the first match is needed and it has been already found
> @@ -3241,7 +3190,7 @@ JOIN_CACHE_BKA_UNIQUE::join_matching_rec
> get_record_by_pos(rec_ptr);
> rc= generate_full_extensions(rec_ptr);
> if (rc != NESTED_LOOP_OK&& rc != NESTED_LOOP_NO_MORE_ROWS)
> - goto finish;
> + return rc;
> }
> }
> while (next_rec_ref_ptr != last_rec_ref_ptr);
> @@ -3249,8 +3198,7 @@ JOIN_CACHE_BKA_UNIQUE::join_matching_rec
>
> if (error> 0&& error != HA_ERR_END_OF_FILE)
> return NESTED_LOOP_ERROR;
> -finish:
> - return end_join_matching_records(rc);
> + return rc;
> }
>
>
>
> === modified file 'sql/sql_select.cc'
> --- a/sql/sql_select.cc 2011-03-03 09:43:14 +0000
> +++ b/sql/sql_select.cc 2011-04-01 09:09:15 +0000
> @@ -11168,7 +11168,7 @@ make_join_readinfo(JOIN *join, ulonglong
> */
> tab->sorted= sorted;
> sorted= 0; // only first must
be sorted
> - table->status=STATUS_NO_RECORD;
> + table->status= STATUS_GARBAGE | STATUS_NOT_FOUND;
> pick_table_access_method (tab);
>
> if (tab->loosescan_match_tab)
> @@ -17960,7 +17960,7 @@ join_read_const_table(JOIN_TAB *tab, POS
> TABLE *table=tab->table;
> table->const_table=1;
> table->null_row=0;
> - table->status=STATUS_NO_RECORD;
> + table->status= STATUS_GARBAGE | STATUS_NOT_FOUND;
>
> if (tab->type == JT_SYSTEM)
> {
> @@ -18154,7 +18154,7 @@ join_read_key2(JOIN_TAB *tab, TABLE *tab
> indices on NOT NULL columns (see create_ref_for_key()).
> */
> if (cmp_buffer_with_ref(tab->join->thd, table, table_ref) ||
> - (table->status& (STATUS_GARBAGE | STATUS_NO_PARENT |
STATUS_NULL_ROW)))
> + (table->status& (STATUS_GARBAGE | STATUS_NULL_ROW)))
> {
> if (table_ref->key_err)
> {
>
> === modified file 'sql/sql_select.h'
> --- a/sql/sql_select.h 2011-03-01 14:57:53 +0000
> +++ b/sql/sql_select.h 2011-04-01 09:09:15 +0000
> @@ -296,7 +296,6 @@ typedef struct st_join_table : public Sq
>
> table_map dependent,key_dependent;
> uint index;
> - uint status; ///< Save status for cache
> uint used_fields,used_fieldlength,used_blobs;
> uint used_null_fields;
> uint used_rowid_fields;
> @@ -470,7 +469,6 @@ st_join_table::st_join_table()
> dependent(0),
> key_dependent(0),
> index(0),
> - status(0),
> used_fields(0),
> used_fieldlength(0),
> used_blobs(0),
> @@ -1032,9 +1030,6 @@ protected:
> enum_nested_loop_state init_join_matching_records(RANGE_SEQ_IF
*seq_funcs,
> uint ranges);
>
> - /* Finish searching for records that match records from the join
buffer */
> - enum_nested_loop_state
end_join_matching_records(enum_nested_loop_state rc);
> -
> public:
>
> /*
>
> === modified file 'sql/structs.h'
> --- a/sql/structs.h 2010-10-21 09:49:16 +0000
> +++ b/sql/structs.h 2011-04-01 09:09:15 +0000
> @@ -231,13 +231,20 @@ typedef struct user_conn {
> #define REG_SKIP_DUP 256
>
> /* Bits in form->status */
> -#define STATUS_NO_RECORD (1+2) /* Record isn't usably */
> #define STATUS_GARBAGE 1
> -#define STATUS_NOT_FOUND 2 /* No record in database when needed */
> -#define STATUS_NO_PARENT 4 /* Parent record wasn't found */
> -#define STATUS_NOT_READ 8 /* Record isn't read */
> -#define STATUS_UPDATED 16 /* Record is updated by formula */
> -#define STATUS_NULL_ROW 32 /* table->null_row is set */
> +/**
> + Means we were searching for a row and didn't find it. This is used by
> + storage engines (@see handler::index_read_map()) and the Server
layer.
> +*/
> +#define STATUS_NOT_FOUND 2
> +/// Reserved for use by multi-table update. Means the row has been
updated.
> +#define STATUS_UPDATED 16
> +/**
> + Means that table->null_row is set. This is an artificial
NULL-filled row
> + (one example: in outer join, if no match has been found in inner
table).
> +*/
> +#define STATUS_NULL_ROW 32
> +/// Reserved for use by multi-table delete. Means the row has been
deleted.
> #define STATUS_DELETED 64
I suggest removing the TABs above.
>
> /*
>
> === modified file 'sql/table.cc'
> --- a/sql/table.cc 2011-02-09 15:17:14 +0000
> +++ b/sql/table.cc 2011-04-01 09:09:15 +0000
> @@ -3301,7 +3301,7 @@ void TABLE::init(THD *thd, TABLE_LIST *t
> force_index= 0;
> force_index_order= 0;
> force_index_group= 0;
> - status= STATUS_NO_RECORD;
> + status= STATUS_GARBAGE | STATUS_NOT_FOUND;
I think it would suffice to initialize status to STATUS_GARBAGE.
AFAICT, there is no test for STATUS_NOT_FOUND that does not also check
STATUS_GARBAGE. Also, comments indicate that STATUS_GARBAGE means
first read. (Same goes for other places that initialize
table->status.)
> insert_values= 0;
> fulltext_searched= 0;
> file->ft_handler= 0;
>
>
>
>
>
--
Øystein
