diff --git a/sql/opt_range.cc b/sql/opt_range.cc index acf69fdd09840e5603a81d83d687ff47b8a53001..e67a9881bba372bed32b1029748923a0ec836655 100644 --- a/sql/opt_range.cc +++ b/sql/opt_range.cc @@ -725,7 +725,7 @@ QUICK_RANGE_SELECT::QUICK_RANGE_SELECT(THD *thd, TABLE *table, uint key_nr, key_part_info= head->key_info[index].key_part; my_init_dynamic_array(&ranges, sizeof(QUICK_RANGE*), 16, 16); - /* 'thd' is not accessible in QUICK_RANGE_SELECT::get_next_init(). */ + /* 'thd' is not accessible in QUICK_RANGE_SELECT::reset(). */ multi_range_bufsiz= thd->variables.read_rnd_buff_size; multi_range_count= thd->variables.multi_range_count; multi_range_length= 0; @@ -749,9 +749,6 @@ int QUICK_RANGE_SELECT::init() { DBUG_ENTER("QUICK_RANGE_SELECT::init"); - if ((error= get_next_init())) - DBUG_RETURN(error); - if (file->inited == handler::NONE) DBUG_RETURN(error= file->ha_index_init(index)); error= 0; @@ -5655,9 +5652,8 @@ int QUICK_INDEX_MERGE_SELECT::read_keys_and_merge() We reuse the same instance of handler so we need to call both init and reset here. */ - if (cur_quick->init()) + if (cur_quick->init() || cur_quick->reset()) DBUG_RETURN(1); - cur_quick->reset(); unique= new Unique(refpos_order_cmp, (void *)head->file, head->file->ref_length, @@ -5675,10 +5671,8 @@ int QUICK_INDEX_MERGE_SELECT::read_keys_and_merge() if (cur_quick->file->inited != handler::NONE) cur_quick->file->ha_index_end(); - if (cur_quick->init()) + if (cur_quick->init() || cur_quick->reset()) DBUG_RETURN(1); - /* QUICK_RANGE_SELECT::reset never fails */ - cur_quick->reset(); } if (result) @@ -5745,9 +5739,8 @@ int QUICK_INDEX_MERGE_SELECT::get_next() if (pk_quick_select) { doing_pk_scan= TRUE; - if ((result= pk_quick_select->init())) + if ((result= pk_quick_select->init()) || (result= pk_quick_select->reset())) DBUG_RETURN(result); - pk_quick_select->reset(); DBUG_RETURN(pk_quick_select->get_next()); } } @@ -5908,28 +5901,15 @@ int QUICK_ROR_UNION_SELECT::get_next() DBUG_RETURN(error); } - -/* - Initialize data structures needed by get_next(). - - SYNOPSIS - QUICK_RANGE_SELECT::get_next_init() - - DESCRIPTION - This is called from get_next() at its first call for an object. - It allocates memory buffers and sets size variables. - - RETURN - 0 OK. - != 0 Error. -*/ - -int QUICK_RANGE_SELECT::get_next_init(void) +int QUICK_RANGE_SELECT::reset() { uint mrange_bufsiz; byte *mrange_buff; - DBUG_ENTER("QUICK_RANGE_SELECT::get_next_init"); - + DBUG_ENTER("QUICK_RANGE_SELECT::reset"); + next=0; + range= NULL; + cur_range= (QUICK_RANGE**) ranges.buffer; + /* Do not allocate the buffers twice. */ if (multi_range_length) { @@ -5937,15 +5917,8 @@ int QUICK_RANGE_SELECT::get_next_init(void) DBUG_RETURN(0); } - /* If the ranges are not yet initialized, wait for the next call. */ - if (! ranges.elements) - { - DBUG_RETURN(0); - } - - /* - Allocate the ranges array. - */ + /* Allocate the ranges array. */ + DBUG_ASSERT(ranges.elements); multi_range_length= min(multi_range_count, ranges.elements); DBUG_ASSERT(multi_range_length > 0); while (multi_range_length && ! (multi_range= (KEY_MULTI_RANGE*) @@ -5962,9 +5935,7 @@ int QUICK_RANGE_SELECT::get_next_init(void) DBUG_RETURN(HA_ERR_OUT_OF_MEM); } - /* - Allocate the handler buffer if necessary. - */ + /* Allocate the handler buffer if necessary. */ if (file->table_flags() & HA_NEED_READ_RANGE_BUFFER) { mrange_bufsiz= min(multi_range_bufsiz, @@ -5992,9 +5963,6 @@ int QUICK_RANGE_SELECT::get_next_init(void) multi_range_buff->buffer_end= mrange_buff + mrange_bufsiz; multi_range_buff->end_of_used_area= mrange_buff; } - - /* Initialize the current QUICK_RANGE pointer. */ - cur_range= (QUICK_RANGE**) ranges.buffer; DBUG_RETURN(0); } @@ -7948,10 +7916,10 @@ int QUICK_GROUP_MIN_MAX_SELECT::reset(void) file->extra(HA_EXTRA_KEYREAD); /* We need only the key attributes */ result= file->ha_index_init(index); result= file->index_last(record); - if (quick_prefix_select) - quick_prefix_select->reset(); if (result) DBUG_RETURN(result); + if (quick_prefix_select && quick_prefix_select->reset()) + DBUG_RETURN(1); /* Save the prefix of the last group. */ key_copy(last_prefix, record, index_info, group_prefix_len); diff --git a/sql/opt_range.h b/sql/opt_range.h index 71981dfb5c741ba9363e2e903bb3f811ae92c9ca..97d646cedbe2d95350b6dae59c2713c6dc16451a 100644 --- a/sql/opt_range.h +++ b/sql/opt_range.h @@ -59,6 +59,44 @@ class QUICK_RANGE :public Sql_alloc { /* Quick select interface. This class is a parent for all QUICK_*_SELECT and FT_SELECT classes. + + The usage scenario is as follows: + 1. Create quick select + quick= new QUICK_XXX_SELECT(...); + + 2. Perform lightweight initialization. This can be done in 2 ways: + 2.a: Regular initialization + if (quick->init()) + { + //the only valid action after failed init() call is delete + delete quick; + } + 2.b: Special initialization for quick selects merged by QUICK_ROR_*_SELECT + if (quick->init_ror_merged_scan()) + delete quick; + + 3. Perform zero, one, or more scans. + while (...) + { + // initialize quick select for scan. This may allocate + // buffers and/or prefetch rows. + if (quick->reset()) + { + //the only valid action after failed reset() call is delete + delete quick; + //abort query + } + + // perform the scan + do + { + res= quick->get_next(); + } while (res && ...) + } + + 4. Delete the select: + delete quick; + */ class QUICK_SELECT_I @@ -117,27 +155,16 @@ public: reset() should be called when it is certain that row retrieval will be necessary. This call may do heavyweight initialization like buffering first N records etc. If reset() call fails get_next() must not be called. - Note that reset() may be called several times if this quick select - executes in a subselect. + Note that reset() may be called several times if + * the quick select is executed in a subselect + * a JOIN buffer is used + RETURN 0 OK other Error code */ virtual int reset(void) = 0; - /* - Initialize get_next() for row retrieval. - SYNOPSIS - get_next_init() - - get_next_init() must be called before the first get_next(). - If get_next_init() call fails get_next() must not be called. - - RETURN - 0 OK - other Error code - */ - virtual int get_next_init() { return false; } virtual int get_next() = 0; /* get next record to retrieve */ /* Range end should be called when we have looped over the whole index */ @@ -284,18 +311,7 @@ public: ~QUICK_RANGE_SELECT(); int init(); - int reset(void) - { - next=0; - range= NULL; - cur_range= (QUICK_RANGE**) ranges.buffer; - /* - Note: in opt_range.cc there are places where it is assumed that this - function always succeeds - */ - return 0; - } - int get_next_init(void); + int reset(void); int get_next(); void range_end(); int get_next_prefix(uint prefix_length, byte *cur_prefix); @@ -310,6 +326,8 @@ public: #ifndef DBUG_OFF void dbug_dump(int indent, bool verbose); #endif +private: + /* Used only by QUICK_SELECT_DESC */ QUICK_RANGE_SELECT(const QUICK_RANGE_SELECT& org) : QUICK_SELECT_I() { bcopy(&org, this, sizeof(*this)); @@ -685,6 +703,7 @@ public: QUICK_RANGE_SELECT (thd, table, key, 1) { init(); } ~FT_SELECT() { file->ft_end(); } int init() { return error=file->ft_init(); } + int reset() { return 0; } int get_next() { return error=file->ft_read(record); } int get_type() { return QS_TYPE_FULLTEXT; } }; diff --git a/sql/records.cc b/sql/records.cc index 9a506cadf0c9115f222606eda8333b9deec0ccf5..00da1ac1adc74ef7b6daf91d311097596fc5dc3c 100644 --- a/sql/records.cc +++ b/sql/records.cc @@ -100,19 +100,8 @@ void init_read_record(READ_RECORD *info,THD *thd, TABLE *table, } else if (select && select->quick) { - int error; DBUG_PRINT("info",("using rr_quick")); - - if (!table->file->inited) - table->file->ha_index_init(select->quick->index); info->read_record=rr_quick; - - if ((error= select->quick->get_next_init())) - { - /* Cannot return error code here. Instead print to error log. */ - table->file->print_error(error,MYF(ME_NOREFRESH)); - thd->fatal_error(); - } } else if (table->sort.record_pointers) {