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MDEV-23908: Implement SELECT ... OFFSET ... FETCH ...

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This commit implements the standard SQL extension
OFFSET start { ROW | ROWS }
[FETCH { FIRST | NEXT } [ count ] { ROW | ROWS } { ONLY | WITH TIES }]

To achieve this a reserved keyword OFFSET is introduced.

The general logic for WITH TIES implies:
1. The number of rows a query returns is no longer known during optimize
   phase. Adjust optimizations to no longer consider this.
2. During end_send make use of an "order Cached_item"to compare if the
   ORDER BY columns changed. Keep returning rows until there is a
   change. This happens only after we reached the row limit.
3. Within end_send_group, the order by clause was eliminated. It is
   still possible to keep the optimization of using end_send_group for
   producing the final result set.
This commit is contained in:
Vicențiu Ciorbaru
2021-03-28 21:41:50 +03:00
parent 2d595319bf
commit 299b935320
19 changed files with 2621 additions and 81 deletions
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2
scripts/mysql_system_tables.sql
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@ -144,7 +144,7 @@ CREATE TABLE IF NOT EXISTS time_zone ( Time_zone_id int unsigned NOT NULL auto
CREATE TABLE IF NOT EXISTS time_zone_transition ( Time_zone_id int unsigned NOT NULL, Transition_time bigint signed NOT NULL, Transition_type_id int unsigned NOT NULL, PRIMARY KEY /*TzIdTranTime*/ (Time_zone_id, Transition_time) ) engine=Aria transactional=1 CHARACTER SET utf8 comment='Time zone transitions';
CREATE TABLE IF NOT EXISTS time_zone_transition_type ( Time_zone_id int unsigned NOT NULL, Transition_type_id int unsigned NOT NULL, Offset int signed DEFAULT 0 NOT NULL, Is_DST tinyint unsigned DEFAULT 0 NOT NULL, Abbreviation char(8) DEFAULT '' NOT NULL, PRIMARY KEY /*TzIdTrTId*/ (Time_zone_id, Transition_type_id) ) engine=Aria transactional=1 CHARACTER SET utf8 comment='Time zone transition types';
CREATE TABLE IF NOT EXISTS time_zone_transition_type ( Time_zone_id int unsigned NOT NULL, Transition_type_id int unsigned NOT NULL, `Offset` int signed DEFAULT 0 NOT NULL, Is_DST tinyint unsigned DEFAULT 0 NOT NULL, Abbreviation char(8) DEFAULT '' NOT NULL, PRIMARY KEY /*TzIdTrTId*/ (Time_zone_id, Transition_type_id) ) engine=Aria transactional=1 CHARACTER SET utf8 comment='Time zone transition types';
CREATE TABLE IF NOT EXISTS time_zone_leap_second ( Transition_time bigint signed NOT NULL, Correction int signed NOT NULL, PRIMARY KEY /*TranTime*/ (Transition_time) ) engine=Aria transactional=1 CHARACTER SET utf8 comment='Leap seconds information for time zones';