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[Maria-developers] per-partition attributes in the CREATE TABLE
by Sergei Golubchik 09 Jun '10

09 Jun '10

Hi, we've talked about engine attributes in the CREATE TABLE, and that one should be able to specify them per partition as well. Now, thinking about it, I'm not quite sure what the semantics shuld be. What is your use case ? How do you want them to work ? I see different possibilities. Say, there is create table ... (.....) XXX=1 partition by list (a) ( partition p0 values in (1) YYY=2, partition p1 values in (2) ); 1. We can say that XXX should be listed in the engine's hton->table_options, and YYY - in the hton->partition_options. this works fine because the engine can use table_share->option_struct and it will contain correct values, independent from whether a table is partitioned or not. but it will break when partitioning will support different engines in different partitions. 2. We can say that XXX is partition engine options, and a pluggable engine can only see YYY. YYY should come from hton->partition_options, and the engine's table level attributes are not applicable. The drawback - every engine needs to have special code to take care of the partitioned case, and to duplicate all table-level options in the partition-level options. 3. Same as 2, but YYY can come from either table level or partition level arrays. Every engine still needs the special code for partitioned case, but does not need to duplicate the table_options array. Regards, Sergei

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[Maria-developers] Ever wanted to save/restore your GDB breakpoints? Here's a solution.
by Timour Katchaounov 09 Jun '10

09 Jun '10

Hi, Today I got really annoyed while debugging a server crash with GDB. I never managed to make the same GDB reattach to a new process after a crash. This means that after each crash one has to restart GDB, and reattach to the new process. As a result all breakpoints are lost, and need to be set each time, which is pretty annoying. Today I thought that others might have been equally annoyed, and might have figured a solution. Indeed, Google is our friend, and I found the following short snippet that should be added to .gdbinit: define bsave shell rm -f brestore.txt set logging file brestore.txt set logging on info break set logging off # reformat on-the-fly to a valid gdb command file shell perl -n -e 'print "break $1\n" if /^\d+.+?(\S+)$/g' brestore.txt > brestore.gdb end document bsave store actual breakpoints end define brestore source brestore.gdb end document brestore restore breakpoints saved by bsave end The credits go to this page: http://stackoverflow.com/questions/501486/getting-gdb-to-save-a-list-of-bre… Happy debugging, Timour

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[Maria-developers] bzr commit into MariaDB 5.1, with Maria 1.5:maria branch (knielsen:2850)
by knielsen＠knielsen-hq.org 09 Jun '10

09 Jun '10

#At lp:maria 2850 knielsen(a)knielsen-hq.org 2010-06-09 MWL#116: Fix a couple of races in group commit. modified: include/atomic/gcc_builtins.h include/atomic/x86-gcc.h sql/handler.cc === modified file 'include/atomic/gcc_builtins.h' --- a/include/atomic/gcc_builtins.h 2008-02-06 16:55:04 +0000 +++ b/include/atomic/gcc_builtins.h 2010-06-09 11:17:39 +0000 @@ -19,8 +19,9 @@ v= __sync_lock_test_and_set(a, v); #define make_atomic_cas_body(S) \ int ## S sav; \ - sav= __sync_val_compare_and_swap(a, *cmp, set); \ - if (!(ret= (sav == *cmp))) *cmp= sav; + int ## S cmp_val= *cmp; \ + sav= __sync_val_compare_and_swap(a, cmp_val, set);\ + if (!(ret= (sav == cmp_val))) *cmp= sav #ifdef MY_ATOMIC_MODE_DUMMY #define make_atomic_load_body(S) ret= *a === modified file 'include/atomic/x86-gcc.h' --- a/include/atomic/x86-gcc.h 2007-02-28 16:50:51 +0000 +++ b/include/atomic/x86-gcc.h 2010-06-09 11:17:39 +0000 @@ -38,15 +38,33 @@ #define asm __asm__ #endif +/* + The atomic operations imply a memory barrier for the CPU, to ensure that all + prior writes are flushed from cache, and all subsequent reads reloaded into + cache. + + We need to imply a similar memory barrier for the compiler, so that all + pending stores (to memory that may be aliased in other parts of the code) + will be flushed to memory before the operation, and all reads from such + memory be re-loaded. This is achieved by adding the "memory" pseudo-register + to the clobber list, see GCC documentation for more explanation. + + The compiler and CPU memory barriers are needed to make sure changes in one + thread are made visible in another by the atomic operation. +*/ #ifndef MY_ATOMIC_NO_XADD #define make_atomic_add_body(S) \ - asm volatile (LOCK_prefix "; xadd %0, %1;" : "+r" (v) , "+m" (*a)) + asm volatile (LOCK_prefix "; xadd %0, %1;" : "+r" (v) , "+m" (*a): : "memory") #endif #define make_atomic_fas_body(S) \ - asm volatile ("xchg %0, %1;" : "+r" (v) , "+m" (*a)) + asm volatile ("xchg %0, %1;" : "+r" (v) , "+m" (*a) : : "memory") #define make_atomic_cas_body(S) \ + int ## S sav; \ asm volatile (LOCK_prefix "; cmpxchg %3, %0; setz %2;" \ - : "+m" (*a), "+a" (*cmp), "=q" (ret): "r" (set)) + : "+m" (*a), "=a" (sav), "=q" (ret) \ + : "r" (set), "a" (*cmp) : "memory"); \ + if (!ret) \ + *cmp= sav #ifdef MY_ATOMIC_MODE_DUMMY #define make_atomic_load_body(S) ret=*a @@ -59,9 +77,9 @@ #define make_atomic_load_body(S) \ ret=0; \ asm volatile (LOCK_prefix "; cmpxchg %2, %0" \ - : "+m" (*a), "+a" (ret): "r" (ret)) + : "+m" (*a), "+a" (ret) : "r" (ret) : "memory") #define make_atomic_store_body(S) \ - asm volatile ("; xchg %0, %1;" : "+m" (*a), "+r" (v)) + asm volatile ("; xchg %0, %1;" : "+m" (*a), "+r" (v) : : "memory") #endif /* TODO test on intel whether the below helps. on AMD it makes no difference */ === modified file 'sql/handler.cc' --- a/sql/handler.cc 2010-05-26 08:16:18 +0000 +++ b/sql/handler.cc 2010-06-09 11:17:39 +0000 @@ -1103,14 +1103,30 @@ ha_check_and_coalesce_trx_read_only(THD static THD * enqueue_atomic(THD *thd) { - my_atomic_rwlock_wrlock(&LOCK_group_commit_queue); + THD *orig_queue; + thd->next_commit_ordered= group_commit_queue; + + my_atomic_rwlock_wrlock(&LOCK_group_commit_queue); + do + { + /* + Save the read value of group_commit_queue in each iteration of the loop. + When my_atomic_casptr() returns TRUE, we know that orig_queue is equal + to the value of group_commit_queue when we enqueued. + + However, as soon as we enqueue, thd->next_commit_ordered may be + invalidated by another thread (the group commit leader). So we need to + save the old queue value in a local variable orig_queue like this. + */ + orig_queue= thd->next_commit_ordered; + } while (!my_atomic_casptr((void **)(&group_commit_queue), (void **)(&thd->next_commit_ordered), - thd)) - ; + thd)); my_atomic_rwlock_wrunlock(&LOCK_group_commit_queue); - return thd->next_commit_ordered; + + return orig_queue; } static THD * @@ -1399,6 +1415,9 @@ int ha_commit_trans(THD *thd, bool all) int cookie; if (tc_log->use_group_log_xid) { + // ToDo: if xid==NULL here, we may use is_group_commit_leader uninitialised. + // ToDo: Same for cookie below when xid==NULL. + // Seems we generally need to check the case xid==NULL. if (is_group_commit_leader) { pthread_mutex_lock(&LOCK_group_commit); @@ -1434,9 +1453,18 @@ int ha_commit_trans(THD *thd, bool all) } pthread_mutex_unlock(&LOCK_group_commit); - /* Wake up everyone except ourself. */ - while ((queue= queue->next_commit_ordered) != NULL) - group_commit_wakeup_other(queue); + /* Wake up everyone except ourself. */ + THD *current= queue->next_commit_ordered; + while (current != NULL) + { + /* + Careful not to access current->next_commit_ordered after waking up + the other thread! As it may change immediately after wakeup. + */ + THD *next= current->next_commit_ordered; + group_commit_wakeup_other(current); + current= next; + } } else {

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[Maria-developers] Fixes for an issue with my_atomic
by Kristian Nielsen 09 Jun '10

09 Jun '10

Hi, I had a problem with my group commit patch, and tracked it down to a problem in my_atomic. The issue is that my_atomic_cas*(val, cmp, new) accesses *cmp after successful CAS operation (in one place reading it, in another place writing it). Here is the fix: Index: work-5.1-groupcommit/include/atomic/gcc_builtins.h =================================================================== --- work-5.1-groupcommit.orig/include/atomic/gcc_builtins.h 2010-06-09 11:53:59.000000000 +0200 +++ work-5.1-groupcommit/include/atomic/gcc_builtins.h 2010-06-09 11:54:06.000000000 +0200 @@ -19,8 +19,9 @@ v= __sync_lock_test_and_set(a, v); #define make_atomic_cas_body(S) \ int ## S sav; \ - sav= __sync_val_compare_and_swap(a, *cmp, set); \ - if (!(ret= (sav == *cmp))) *cmp= sav; + int ## S cmp_val= *cmp; \ + sav= __sync_val_compare_and_swap(a, cmp_val, set);\ + if (!(ret= (sav == cmp_val))) *cmp= sav #ifdef MY_ATOMIC_MODE_DUMMY #define make_atomic_load_body(S) ret= *a Index: work-5.1-groupcommit/include/atomic/x86-gcc.h =================================================================== --- work-5.1-groupcommit.orig/include/atomic/x86-gcc.h 2010-06-09 11:53:59.000000000 +0200 +++ work-5.1-groupcommit/include/atomic/x86-gcc.h 2010-06-09 11:54:06.000000000 +0200 @@ -45,8 +45,12 @@ #define make_atomic_fas_body(S) \ asm volatile ("xchg %0, %1;" : "+r" (v) , "+m" (*a)) #define make_atomic_cas_body(S) \ + int ## S sav; \ asm volatile (LOCK_prefix "; cmpxchg %3, %0; setz %2;" \ - : "+m" (*a), "+a" (*cmp), "=q" (ret): "r" (set)) + : "+m" (*a), "=a" (sav), "=q" (ret) \ + : "r" (set), "a" (*cmp)); \ + if (!ret) \ + *cmp= sav #ifdef MY_ATOMIC_MODE_DUMMY #define make_atomic_load_body(S) ret=*a This makes the behaviour consistent with the other implementations, see for example generic-msvc.h. (It is also pretty important for correct operation. In my code, I use my_atomic_casptr() to atomically enqueue a struct from one thread, and as soon as it is enqueued another thread may grab the struct and change it, including the field pointed to by cmp. So it is essential that my_atomic_casptr() neither reads nor writes *cmp after successful CAS, as the above patch ensures.) It was btw. a bit funny how I tracked this down. After digging for a few hours in my own code without success I got the idea to check the CAS implementation, and spotted the problem in gcc_builtins.h. After fixing I was baffled as to why my code stil failed, until I realised I was not using gcc_builtins.h but x86-gcc.h, and found and fixed the similar problem there ;-) Now the question is, where should I push this (if at all)? Any opinions? ----------------------------------------------------------------------- While I was there, I also noticed another potential problem in gcc_builtins.h, suggesting this patch: Index: work-5.1-groupcommit/include/atomic/x86-gcc.h =================================================================== --- work-5.1-groupcommit.orig/include/atomic/x86-gcc.h 2010-06-09 11:37:12.000000000 +0200 +++ work-5.1-groupcommit/include/atomic/x86-gcc.h 2010-06-09 11:52:47.000000000 +0200 @@ -38,17 +38,31 @@ #define asm __asm__ #endif +/* + The atomic operations imply a memory barrier for the CPU, to ensure that all + prior writes are flushed from cache, and all subsequent reads reloaded into + cache. + + We need to imply a similar memory barrier for the compiler, so that all + pending stores (to memory that may be aliased in other parts of the code) + will be flushed to memory before the operation, and all reads from such + memory be re-loaded. This is achieved by adding the "memory" pseudo-register + to the clobber list, see GCC documentation for more explanation. + + The compiler and CPU memory barriers are needed to make sure changes in one + thread are made visible in another by the atomic operation. +*/ #ifndef MY_ATOMIC_NO_XADD #define make_atomic_add_body(S) \ - asm volatile (LOCK_prefix "; xadd %0, %1;" : "+r" (v) , "+m" (*a)) + asm volatile (LOCK_prefix "; xadd %0, %1;" : "+r" (v) , "+m" (*a): : "memory") #endif #define make_atomic_fas_body(S) \ - asm volatile ("xchg %0, %1;" : "+r" (v) , "+m" (*a)) + asm volatile ("xchg %0, %1;" : "+r" (v) , "+m" (*a) : : "memory") #define make_atomic_cas_body(S) \ int ## S sav; \ asm volatile (LOCK_prefix "; cmpxchg %3, %0; setz %2;" \ : "+m" (*a), "=a" (sav), "=q" (ret) \ - : "r" (set), "a" (*cmp)); \ + : "r" (set), "a" (*cmp) : "memory"); \ if (!ret) \ *cmp= sav @@ -63,9 +77,9 @@ #define make_atomic_load_body(S) \ ret=0; \ asm volatile (LOCK_prefix "; cmpxchg %2, %0" \ - : "+m" (*a), "+a" (ret): "r" (ret)) + : "+m" (*a), "+a" (ret) : "r" (ret) : "memory") #define make_atomic_store_body(S) \ - asm volatile ("; xchg %0, %1;" : "+m" (*a), "+r" (v)) + asm volatile ("; xchg %0, %1;" : "+m" (*a), "+r" (v) : : "memory") #endif /* TODO test on intel whether the below helps. on AMD it makes no difference */ The comment in the patch explains the idea I think. Basically, these memory barrier operations need to be a compiler barrier also. Otherwise there is nothing that prevents GCC from moving unrelated stores across the memory barrier operation. This is a problem for example when filling in a structure and then atomically linking it into a shared list. The CPU memory barrier ensures that the fields in the structure will be visible to other threads on the CPU level, but it is also necessary to tell GCC to keep the stores into the struct fields prior to the store linking into the shared list. (It also makes the volatile declaration on the updated memory location unnecessary, but maybe it is needed for other implementations (though it shouldn't be, volatile is almost always wrong)). - Kristian.

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[Maria-developers] Patch to build xtradb and federatedx statically on Windows
by Bo Thorsen 09 Jun '10

09 Jun '10

Hi everyone, Recently, we found out that xtradb and federatedx were compiled as plugins on Windows. This is not correct because they are core storage engines and should be linked statically instead. On Unix, it's possible to build both types, but the CMake files doesn't really handle this. They just look in plug.in, and if there is a dynamic line, the storage engine is built dynamically. I'm hesitant to fix this properly, as it's probably already done in MySQL 5.5, or at least it will be. I see no reason to come up with a good solution for a temporary problem - there are many other issues on Windows that are more pressing. FederatedX couldn't compile as a statically linked plugin at all on Windows. I have fixed this now, but I *really* don't like the way we do these hacks on Windows. It's absurdly difficult to keep track of when a variable says xtradb and when it says innobase. And debugging CMakeLists.txt files is not too much fun. Anyway, I did the same thing on FederatedX as is done in XtraDB, and it works now. Finally, I removed a subdir that didn't have a CMakeLists.txt. Removed a warning during the cmake run. With this patch, the Windows zip file release build should work correctly and produce a MariaDB with both XtraDB and FederatedX in it. Should I check this into ~maria-captains/maria/5.1, or is there a branch more suitable at the moment? Bo Thorsen. Monty Program AB. -- MariaDB: MySQL replacement Community developed. Feature enhanced. Backward compatible.

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[Maria-developers] Rev 2795: Uninitialized memory problem fixed. in file:///home/bell/maria/bzr/work-maria-5.3-scache2/
by sanja＠askmonty.org 08 Jun '10

08 Jun '10

At file:///home/bell/maria/bzr/work-maria-5.3-scache2/ ------------------------------------------------------------ revno: 2795 revision-id: sanja(a)askmonty.org-20100608122454-dtlvue8n2s55yi67 parent: sanja(a)askmonty.org-20100608120847-v4loj2gdqjflbarv committer: sanja(a)askmonty.org branch nick: work-maria-5.3-scache2 timestamp: Tue 2010-06-08 15:24:54 +0300 message: Uninitialized memory problem fixed. === modified file 'sql/table.cc' --- a/sql/table.cc 2010-06-07 07:58:45 +0000 +++ b/sql/table.cc 2010-06-08 12:24:54 +0000 @@ -5176,6 +5176,7 @@ key_part_info->offset= (*reg_field)->offset(record[0]); key_part_info->length= (uint16) (*reg_field)->pack_length(); keyinfo->key_length+= key_part_info->length; + key_part_info->key_part_flag= 0; /* TODO: The below method of computing the key format length of the key part is a copy/paste from opt_range.cc, and table.cc.

1 0

[Maria-developers] Rev 2794: Fixed uninitialized memory in file:///home/bell/maria/bzr/work-maria-5.3-scache2/
by sanja＠askmonty.org 08 Jun '10

08 Jun '10

At file:///home/bell/maria/bzr/work-maria-5.3-scache2/ ------------------------------------------------------------ revno: 2794 revision-id: sanja(a)askmonty.org-20100608120847-v4loj2gdqjflbarv parent: sanja(a)askmonty.org-20100608114156-36q3me04ecxh2by6 committer: sanja(a)askmonty.org branch nick: work-maria-5.3-scache2 timestamp: Tue 2010-06-08 15:08:47 +0300 message: Fixed uninitialized memory === modified file 'sql/sql_subquery_cache.cc' --- a/sql/sql_subquery_cache.cc 2010-06-08 11:41:56 +0000 +++ b/sql/sql_subquery_cache.cc 2010-06-08 12:08:47 +0000 @@ -50,6 +50,7 @@ tab_ref->null_rejecting= 1; tab_ref->disable_cache= FALSE; tab_ref->has_record= 0; + tab_ref->use_count= 0; KEY_PART_INFO *cur_key_part= tmp_key->key_part; store_key **ref_key= tab_ref->key_copy;

1 0

[Maria-developers] Rev 2793: Fixed uninitialized memory. in file:///home/bell/maria/bzr/work-maria-5.3-scache2/
by sanja＠askmonty.org 08 Jun '10

08 Jun '10

At file:///home/bell/maria/bzr/work-maria-5.3-scache2/ ------------------------------------------------------------ revno: 2793 revision-id: sanja(a)askmonty.org-20100608114156-36q3me04ecxh2by6 parent: sanja(a)askmonty.org-20100608093610-efg156vu4mi4u9pp committer: sanja(a)askmonty.org branch nick: work-maria-5.3-scache2 timestamp: Tue 2010-06-08 14:41:56 +0300 message: Fixed uninitialized memory. === modified file 'sql/mysql_priv.h' --- a/sql/mysql_priv.h 2010-05-31 21:25:54 +0000 +++ b/sql/mysql_priv.h 2010-06-08 11:41:56 +0000 @@ -1274,7 +1274,7 @@ select_result *result, SELECT_LEX_UNIT *unit, SELECT_LEX *select_lex); -struct st_join_table *create_index_lookup_join_tab(TABLE *table); +struct st_join_table *create_index_lookup_join_tab(TABLE *table, int key_no); int join_read_key2(THD *thd, struct st_join_table *tab, TABLE *table, struct st_table_ref *table_ref); void free_underlaid_joins(THD *thd, SELECT_LEX *select); === modified file 'sql/sql_select.cc' --- a/sql/sql_select.cc 2010-05-31 21:25:54 +0000 +++ b/sql/sql_select.cc 2010-06-08 11:41:56 +0000 @@ -7627,11 +7627,12 @@ Creates and fills JOIN_TAB for index look up in temporary table @param table The table where to look up + @param key_no Number of key @return JOIN_TAB object or NULL in case of error */ -JOIN_TAB *create_index_lookup_join_tab(TABLE *table) +JOIN_TAB *create_index_lookup_join_tab(TABLE *table, int key_no) { JOIN_TAB *tab; DBUG_ENTER("create_index_lookup_join_tab"); @@ -7640,13 +7641,12 @@ DBUG_RETURN(NULL); tab->read_record.table= table; tab->read_record.file=table->file; - /*tab->read_record.unlock_row= rr_unlock_row;*/ tab->next_select=0; tab->sorted= 1; + tab->ref.key= key_no; table->status= STATUS_NO_RECORD; tab->read_first_record= join_read_key; - /*tab->read_record.unlock_row= join_read_key_unlock_row;*/ tab->read_record.read_record= join_no_more_records; if (table->covering_keys.is_set(tab->ref.key) && !table->no_keyread) === modified file 'sql/sql_subquery_cache.cc' --- a/sql/sql_subquery_cache.cc 2010-05-31 21:25:54 +0000 +++ b/sql/sql_subquery_cache.cc 2010-06-08 11:41:56 +0000 @@ -225,7 +225,7 @@ (uchar*)&field_counter) < 0) || createtmp_table_search_structures(table_thd, cache_table, li_items, &tab_ref) || - !(tab= create_index_lookup_join_tab(cache_table))) + !(tab= create_index_lookup_join_tab(cache_table, 0))) { DBUG_PRINT("error", ("creating index failed")); goto error;

1 0

[Maria-developers] Rev 2792: Fixed memory management problem (Item can't contain other Item due to way of Items destruction). in file:///home/bell/maria/bzr/work-maria-5.3-scache2/
by sanja＠askmonty.org 08 Jun '10

08 Jun '10

At file:///home/bell/maria/bzr/work-maria-5.3-scache2/ ------------------------------------------------------------ revno: 2792 revision-id: sanja(a)askmonty.org-20100608093610-efg156vu4mi4u9pp parent: sanja(a)askmonty.org-20100608074734-1m60ib2tac7y9m33 committer: sanja(a)askmonty.org branch nick: work-maria-5.3-scache2 timestamp: Tue 2010-06-08 12:36:10 +0300 message: Fixed memory management problem (Item can't contain other Item due to way of Items destruction). === modified file 'sql/item_cmpfunc.cc' --- a/sql/item_cmpfunc.cc 2010-05-31 21:25:54 +0000 +++ b/sql/item_cmpfunc.cc 2010-06-08 09:36:10 +0000 @@ -1737,13 +1737,16 @@ not_null_tables_cache|= args[1]->not_null_tables(); const_item_cache&= args[1]->const_item(); DBUG_ASSERT(scache == NULL); + DBUG_ASSERT(value_for_scache == NULL); if (args[0]->cols() ==1 && thd->variables.optimizer_switch & OPTIMIZER_SWITCH_SUBQUERY_CACHE && !(sub->engine->uncacheable() & (UNCACHEABLE_RAND | UNCACHEABLE_SIDEEFFECT))) { sub->depends_on.push_front((Item**)&cache); - scache= new Subquery_cache_tmptable(thd, sub->depends_on, &result); + value_for_scache= new Item_bool_cache; + scache= new Subquery_cache_tmptable(thd, sub->depends_on, + value_for_scache); } fixed= 1; return FALSE; @@ -1851,8 +1854,8 @@ /* put result in the cache */ if (scache) { - result.set(tmp, null_value); - scache->put_value(&result); + value_for_scache->set(tmp, null_value); + scache->put_value(value_for_scache); } DBUG_RETURN(tmp); } @@ -1876,6 +1879,7 @@ delete scache; scache= 0; } + value_for_scache= 0; DBUG_VOID_RETURN; } === modified file 'sql/item_cmpfunc.h' --- a/sql/item_cmpfunc.h 2010-05-31 21:25:54 +0000 +++ b/sql/item_cmpfunc.h 2010-06-08 09:36:10 +0000 @@ -241,7 +241,7 @@ /* Subquery cache */ Subquery_cache *scache; /* result representation for the subquery cache */ - Item_bool_cache result; + Item_bool_cache *value_for_scache; bool save_cache; /* Stores the value of "NULL IN (SELECT ...)" for uncorrelated subqueries: @@ -252,7 +252,8 @@ my_bool result_for_null_param; public: Item_in_optimizer(Item *a, Item_in_subselect *b): - Item_bool_func(a, my_reinterpret_cast(Item *)(b)), cache(0), scache(NULL), + Item_bool_func(a, my_reinterpret_cast(Item *)(b)), cache(0), + scache(NULL), value_for_scache(NULL), save_cache(0), result_for_null_param(UNKNOWN) {} bool fix_fields(THD *, Item **); === modified file 'sql/item_subselect.cc' --- a/sql/item_subselect.cc 2010-05-31 21:25:54 +0000 +++ b/sql/item_subselect.cc 2010-06-08 09:36:10 +0000 @@ -34,10 +34,10 @@ Item_subselect::Item_subselect(): Item_result_field(), value_assigned(0), thd(0), substitution(0), - engine(0), old_engine(0), scache(0), used_tables_cache(0), - have_to_be_excluded(0), const_item_cache(1), inside_first_fix_fields(0), - done_first_fix_fields(FALSE), eliminated(FALSE), engine_changed(0), - changed(0), is_correlated(FALSE) + engine(0), old_engine(0), scache(0), value_for_scache(0), + used_tables_cache(0), have_to_be_excluded(0), const_item_cache(1), + inside_first_fix_fields(0), done_first_fix_fields(FALSE), + eliminated(FALSE), engine_changed(0), changed(0), is_correlated(FALSE) { with_subselect= 1; reset(); @@ -121,6 +121,7 @@ delete scache; scache= 0; } + value_for_scache= 0; reset(); value_assigned= 0; DBUG_VOID_RETURN; @@ -129,7 +130,7 @@ void Item_singlerow_subselect::cleanup() { DBUG_ENTER("Item_singlerow_subselect::cleanup"); - value= 0; row= 0; + value= 0; row= 0; null_value_item= 0; Item_subselect::cleanup(); DBUG_VOID_RETURN; } @@ -572,7 +573,7 @@ Item_singlerow_subselect::Item_singlerow_subselect(st_select_lex *select_lex) - :Item_subselect(), value(0) + :Item_subselect(), value(0), null_value_item(0) { DBUG_ENTER("Item_singlerow_subselect::Item_singlerow_subselect"); init(select_lex, new select_singlerow_subselect(this)); @@ -760,6 +761,7 @@ (uint)depends_on.elements, (uint)test(thd->variables.optimizer_switch & OPTIMIZER_SWITCH_SUBQUERY_CACHE))); engine->fix_length_and_dec(row= &value); + DBUG_ASSERT(scache == NULL); if (depends_on.elements && optimizer_flag(thd, OPTIMIZER_SWITCH_SUBQUERY_CACHE) && !(engine->uncacheable() & (UNCACHEABLE_RAND | @@ -839,6 +841,22 @@ DBUG_RETURN(NULL); } + +/** + Puts NULL value as result in the cache +*/ + +void Item_singlerow_subselect::put_null_value_in_scache() +{ + if (!value_for_scache) + { + value_for_scache= new Item_bool_cache; + value_for_scache->set(0, TRUE); // NULL + } + DBUG_ASSERT(value_for_scache->null_value); + scache->put_value(value_for_scache); +} + double Item_singlerow_subselect::val_real() { Item *cached_value; @@ -870,7 +888,7 @@ reset(); DBUG_PRINT("info", ("error: %u", (uint)err)); if (scache && !err) - scache->put_value(&const_null_value); + put_null_value_in_scache(); DBUG_RETURN(0); } } @@ -906,7 +924,7 @@ reset(); DBUG_PRINT("info", ("error: %u", (uint)err)); if (scache && !err) - scache->put_value(&const_null_value); + put_null_value_in_scache(); DBUG_RETURN(0); } } @@ -942,7 +960,7 @@ reset(); DBUG_PRINT("info", ("error: %u", (uint)err)); if (scache && !err) - scache->put_value(&const_null_value); + put_null_value_in_scache(); DBUG_RETURN(0); } } @@ -979,7 +997,7 @@ reset(); DBUG_PRINT("info", ("error: %u", (uint)err)); if (scache && !err) - scache->put_value(&const_null_value); + put_null_value_in_scache(); DBUG_RETURN(0); } } @@ -1016,7 +1034,7 @@ reset(); DBUG_PRINT("info", ("error: %u", (uint)err)); if (scache && !err) - scache->put_value(&const_null_value); + put_null_value_in_scache(); DBUG_RETURN(0); } } @@ -1108,13 +1126,16 @@ max_columns= engine->cols(); /* We need only 1 row to determine existence */ unit->global_parameters->select_limit= new Item_int((int32) 1); + + DBUG_ASSERT(scache == NULL); + DBUG_ASSERT(value_for_scache == NULL); if (substype() == EXISTS_SUBS && depends_on.elements && optimizer_flag(thd, OPTIMIZER_SWITCH_SUBQUERY_CACHE) && !(engine->uncacheable() & (UNCACHEABLE_RAND | UNCACHEABLE_SIDEEFFECT))) { - DBUG_ASSERT(scache == NULL); - scache= new Subquery_cache_tmptable(thd, depends_on, &result); + value_for_scache= new Item_bool_cache; + scache= new Subquery_cache_tmptable(thd, depends_on, value_for_scache); DBUG_PRINT("info", ("cache: 0x%lx", (ulong) scache)); } DBUG_VOID_RETURN; @@ -1141,8 +1162,8 @@ if (scache) { - result.set(value, FALSE); - scache->put_value(&result); + value_for_scache->set(value, FALSE); + scache->put_value(value_for_scache); } DBUG_RETURN((double) value); @@ -1170,8 +1191,8 @@ if (scache) { - result.set(value, FALSE); - scache->put_value(&result); + value_for_scache->set(value, FALSE); + scache->put_value(value_for_scache); } DBUG_RETURN(value); @@ -1213,8 +1234,8 @@ if (scache) { - result.set(value, FALSE); - scache->put_value(&result); + value_for_scache->set(value, FALSE); + scache->put_value(value_for_scache); } str->set((ulonglong)value,&my_charset_bin); @@ -1257,8 +1278,8 @@ if (scache) { - result.set(value, FALSE); - scache->put_value(&result); + value_for_scache->set(value, FALSE); + scache->put_value(value_for_scache); } int2my_decimal(E_DEC_FATAL_ERROR, value, 0, decimal_value); @@ -1287,8 +1308,8 @@ if (scache) { - result.set(value, FALSE); - scache->put_value(&result); + value_for_scache->set(value, FALSE); + scache->put_value(value_for_scache); } DBUG_RETURN(value != 0); === modified file 'sql/item_subselect.h' --- a/sql/item_subselect.h 2010-05-31 21:25:54 +0000 +++ b/sql/item_subselect.h 2010-06-08 09:36:10 +0000 @@ -60,8 +60,8 @@ subselect_engine *old_engine; /* subquery cache */ Subquery_cache *scache; - /* null consrtant for caching */ - Item_null const_null_value; + /* subquery cache value for NULL and TRUE/FALSE subqueries */ + Item_bool_cache *value_for_scache; /* cache of used external tables */ table_map used_tables_cache; /* allowed number of columns (1 for single value subqueries) */ @@ -217,10 +217,15 @@ { protected: Item_cache *value, **row; + /* null value for subquery cache value */ + Item_null *null_value_item; + + void put_null_value_in_scache(); public: Item_singlerow_subselect(st_select_lex *select_lex); - Item_singlerow_subselect() :Item_subselect(), value(0), row (0) {} + Item_singlerow_subselect() :Item_subselect(), value(0), row (0), + null_value_item(0) {} void cleanup(); subs_type substype() { return SINGLEROW_SUBS; } @@ -284,8 +289,6 @@ { protected: bool value; /* value of this item (boolean: exists/not-exists) */ - /* result representation for the subquery cache */ - Item_bool_cache result; public: Item_exists_subselect(st_select_lex *select_lex);

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[Maria-developers] Build Slaves
by Adam M. Dutko 08 Jun '10

08 Jun '10

Is the adutko-ultrasparc3 buildbot too slow? would it be missed?

2 1