diff --git a/mysql-test/r/innodb_mysql.result b/mysql-test/r/innodb_mysql.result index b487cfd9a4b099334987ead0bd9f2357be3c2865..47fa331c9ab35145d22b5818ddf8cca5ada77a41 100644 --- a/mysql-test/r/innodb_mysql.result +++ b/mysql-test/r/innodb_mysql.result @@ -1246,4 +1246,19 @@ set global innodb_autoextend_increment=@my_innodb_autoextend_increment; set @my_innodb_commit_concurrency=@@global.innodb_commit_concurrency; set global innodb_commit_concurrency=0; set global innodb_commit_concurrency=@my_innodb_commit_concurrency; +CREATE TABLE t1 (a int, b int, c int, PRIMARY KEY (a), KEY t1_b (b)) +ENGINE=InnoDB; +INSERT INTO t1 (a,b,c) VALUES (1,1,1), (2,1,1), (3,1,1), (4,1,1); +INSERT INTO t1 (a,b,c) SELECT a+4,b,c FROM t1; +EXPLAIN SELECT a, b, c FROM t1 WHERE b = 1 ORDER BY a DESC LIMIT 5; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 range t1_b t1_b 5 NULL 4 Using where +SELECT a, b, c FROM t1 WHERE b = 1 ORDER BY a DESC LIMIT 5; +a b c +8 1 1 +7 1 1 +6 1 1 +5 1 1 +4 1 1 +DROP TABLE t1; End of 5.0 tests diff --git a/mysql-test/t/innodb_mysql.test b/mysql-test/t/innodb_mysql.test index 59ee7c274bbddb698f3cae360dea5da6ed8a9936..e15d1aee08a3461877f9dcda209983cfb48df3a8 100644 --- a/mysql-test/t/innodb_mysql.test +++ b/mysql-test/t/innodb_mysql.test @@ -996,4 +996,22 @@ set @my_innodb_commit_concurrency=@@global.innodb_commit_concurrency; set global innodb_commit_concurrency=0; set global innodb_commit_concurrency=@my_innodb_commit_concurrency; +# +# Bug #37830: ORDER BY ASC/DESC - no difference +# + +CREATE TABLE t1 (a int, b int, c int, PRIMARY KEY (a), KEY t1_b (b)) + ENGINE=InnoDB; + +INSERT INTO t1 (a,b,c) VALUES (1,1,1), (2,1,1), (3,1,1), (4,1,1); +INSERT INTO t1 (a,b,c) SELECT a+4,b,c FROM t1; + +# should be range access +EXPLAIN SELECT a, b, c FROM t1 WHERE b = 1 ORDER BY a DESC LIMIT 5; + +# should produce '8 7 6 5 4' for a +SELECT a, b, c FROM t1 WHERE b = 1 ORDER BY a DESC LIMIT 5; + +DROP TABLE t1; + --echo End of 5.0 tests diff --git a/sql/opt_range.cc b/sql/opt_range.cc index 95cda371673b805b552ded747d55f52bbfb1f652..7587db4e3298f945f6b90d1e5a57305fe3194b17 100644 --- a/sql/opt_range.cc +++ b/sql/opt_range.cc @@ -7099,7 +7099,8 @@ bool QUICK_RANGE_SELECT::row_in_ranges() QUICK_SELECT_DESC::QUICK_SELECT_DESC(QUICK_RANGE_SELECT *q, uint used_key_parts_arg) - : QUICK_RANGE_SELECT(*q), rev_it(rev_ranges) + : QUICK_RANGE_SELECT(*q), rev_it(rev_ranges), + used_key_parts (used_key_parts_arg) { QUICK_RANGE *r; @@ -7141,10 +7142,11 @@ int QUICK_SELECT_DESC::get_next() int result; if (last_range) { // Already read through key - result = ((last_range->flag & EQ_RANGE) - ? file->index_next_same(record, (byte*) last_range->min_key, - last_range->min_length) : - file->index_prev(record)); + result = ((last_range->flag & EQ_RANGE && + used_key_parts <= head->key_info[index].key_parts) ? + file->index_next_same(record, (byte*) last_range->min_key, + last_range->min_length) : + file->index_prev(record)); if (!result) { if (cmp_prev(*rev_it.ref()) == 0) @@ -7168,7 +7170,9 @@ int QUICK_SELECT_DESC::get_next() continue; } - if (last_range->flag & EQ_RANGE) + if (last_range->flag & EQ_RANGE && + used_key_parts <= head->key_info[index].key_parts) + { result= file->index_read(record, (byte*) last_range->max_key, last_range->max_length, HA_READ_KEY_EXACT); @@ -7176,6 +7180,8 @@ int QUICK_SELECT_DESC::get_next() else { DBUG_ASSERT(last_range->flag & NEAR_MAX || + (last_range->flag & EQ_RANGE && + used_key_parts > head->key_info[index].key_parts) || range_reads_after_key(last_range)); result=file->index_read(record, (byte*) last_range->max_key, last_range->max_length, @@ -7273,54 +7279,6 @@ bool QUICK_SELECT_DESC::range_reads_after_key(QUICK_RANGE *range_arg) } -/* TRUE if we are reading over a key that may have a NULL value */ - -#ifdef NOT_USED -bool QUICK_SELECT_DESC::test_if_null_range(QUICK_RANGE *range_arg, - uint used_key_parts) -{ - uint offset, end; - KEY_PART *key_part = key_parts, - *key_part_end= key_part+used_key_parts; - - for (offset= 0, end = min(range_arg->min_length, range_arg->max_length) ; - offset < end && key_part != key_part_end ; - offset+= key_part++->store_length) - { - if (!memcmp((char*) range_arg->min_key+offset, - (char*) range_arg->max_key+offset, - key_part->store_length)) - continue; - - if (key_part->null_bit && range_arg->min_key[offset]) - return 1; // min_key is null and max_key isn't - // Range doesn't cover NULL. This is ok if there is no more null parts - break; - } - /* - If the next min_range is > NULL, then we can use this, even if - it's a NULL key - Example: SELECT * FROM t1 WHERE a = 2 AND b >0 ORDER BY a DESC,b DESC; - - */ - if (key_part != key_part_end && key_part->null_bit) - { - if (offset >= range_arg->min_length || range_arg->min_key[offset]) - return 1; // Could be null - key_part++; - } - /* - If any of the key parts used in the ORDER BY could be NULL, we can't - use the key to sort the data. - */ - for (; key_part != key_part_end ; key_part++) - if (key_part->null_bit) - return 1; // Covers null part - return 0; -} -#endif - - void QUICK_RANGE_SELECT::add_info_string(String *str) { KEY *key_info= head->key_info + index; diff --git a/sql/opt_range.h b/sql/opt_range.h index 3a737323eb7db2c018d3ba4bf0831ad03a4ebd42..8856223b371e5107adb3631e053ad10cc16529d4 100644 --- a/sql/opt_range.h +++ b/sql/opt_range.h @@ -667,12 +667,10 @@ class QUICK_SELECT_DESC: public QUICK_RANGE_SELECT int get_type() { return QS_TYPE_RANGE_DESC; } private: bool range_reads_after_key(QUICK_RANGE *range); -#ifdef NOT_USED - bool test_if_null_range(QUICK_RANGE *range, uint used_key_parts); -#endif int reset(void) { rev_it.rewind(); return QUICK_RANGE_SELECT::reset(); } List<QUICK_RANGE> rev_ranges; List_iterator<QUICK_RANGE> rev_it; + uint used_key_parts; }; diff --git a/sql/sql_select.cc b/sql/sql_select.cc index 60ba7591726e0ffe5cfcbb3ccfb07e31715319a7..bcc5f30180f97d33b283e97868d668688272b90b 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -12088,26 +12088,25 @@ part_of_refkey(TABLE *table,Field *field) } -/***************************************************************************** - Test if one can use the key to resolve ORDER BY - - SYNOPSIS - test_if_order_by_key() - order Sort order - table Table to sort - idx Index to check - used_key_parts Return value for used key parts. - - - NOTES - used_key_parts is set to correct key parts used if return value != 0 - (On other cases, used_key_part may be changed) - - RETURN - 1 key is ok. - 0 Key can't be used - -1 Reverse key can be used -*****************************************************************************/ +/** + Test if a key can be used to resolve ORDER BY + + used_key_parts is set to correct key parts used if return value != 0 + (On other cases, used_key_part may be changed). + Note that the value may actually be greater than the number of index + key parts. This can happen for storage engines that have the primary + key parts as a suffix for every secondary key. + + @param order Sort order + @param table Table to sort + @param idx Index to check + @param[out] used_key_parts Return value for used key parts. + + @return indication if the key can be used for sorting + @retval 1 key can be used for reading data in order. + @retval 0 Key can't be used + @retval -1 Reverse read on the key can be used +*/ static int test_if_order_by_key(ORDER *order, TABLE *table, uint idx, uint *used_key_parts) @@ -12172,11 +12171,27 @@ static int test_if_order_by_key(ORDER *order, TABLE *table, uint idx, reverse=flag; // Remember if reverse key_part++; } - *used_key_parts= on_primary_key ? table->key_info[idx].key_parts : - (uint) (key_part - table->key_info[idx].key_part); - if (reverse == -1 && !(table->file->index_flags(idx, *used_key_parts-1, 1) & - HA_READ_PREV)) - reverse= 0; // Index can't be used + if (on_primary_key) + { + uint used_key_parts_secondary= table->key_info[idx].key_parts; + uint used_key_parts_pk= + (uint) (key_part - table->key_info[table->s->primary_key].key_part); + *used_key_parts= used_key_parts_pk + used_key_parts_secondary; + + if (reverse == -1 && + (!(table->file->index_flags(idx, used_key_parts_secondary - 1, 1) & + HA_READ_PREV) || + !(table->file->index_flags(table->s->primary_key, + used_key_parts_pk - 1, 1) & HA_READ_PREV))) + reverse= 0; // Index can't be used + } + else + { + *used_key_parts= (uint) (key_part - table->key_info[idx].key_part); + if (reverse == -1 && + !(table->file->index_flags(idx, *used_key_parts-1, 1) & HA_READ_PREV)) + reverse= 0; // Index can't be used + } DBUG_RETURN(reverse); }