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e56f6c585e
Timestamp-versioned row deletion was exposed to a collisional problem: if current timestamp wasn't changed, then a sequence of row delete+insert could get a duplication error. A row delete would find another conflicting history row and return an error. This is true both for REPLACE and DELETE statements, however in REPLACE, the "optimized" path is usually taken, especially in the tests. There, delete+insert is substituted for a single versioned row update. In the end, both paths end up as ha_update_row + ha_write_row. The solution is to handle a history collision somehow. From the design perspective, the user shouldn't experience history rows loss, unless there's a technical limitation. To the contrary, trxid-based changes should never generate history for the same transaction, see MDEV-15427. If two operations on the same row happened too quickly, so that they happen at the same timestamp, the history row shouldn't be lost. We can still write a history row, though it'll have row_start == row_end. We cannot store more than one such historical row, as this will violate the unique constraint on row_end. So we will have to phisically delete the row if the history row is already available. In this commit: 1. Improve TABLE::delete_row to handle the history collision: if an update results with a duplicate error, delete a row for real. 2. use TABLE::delete_row in a non-optimistic path of REPLACE, where the system-versioned case now belongs entirely.
80 lines
2.6 KiB
Text
80 lines
2.6 KiB
Text
create table t1(
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x int unsigned,
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sys_start bigint unsigned as row start invisible,
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sys_end bigint unsigned as row end invisible,
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period for system_time (sys_start, sys_end))
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with system versioning engine=innodb;
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create table t2(x int unsigned) engine=innodb;
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start transaction;
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insert into t1(x) values(1);
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commit;
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start transaction;
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insert into t2(x) values(1);
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savepoint a;
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insert into t1(x) values(1);
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rollback to a;
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commit;
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insert into t2(x) values (1);
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create or replace table t1 (
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x int,
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y int as (x) virtual,
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sys_trx_start bigint unsigned as row start invisible,
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sys_trx_end bigint unsigned as row end invisible,
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period for system_time (sys_trx_start, sys_trx_end)
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) engine=innodb with system versioning;
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insert into t1 values (1, null);
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update t1 set x= x + 1;
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select x, y, sys_trx_end = 18446744073709551615 as current from t1 for system_time all;
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x y current
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2 2 1
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1 1 0
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create or replace table t1 (
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x int,
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row_start timestamp(6) as row start invisible,
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row_end timestamp(6) as row end invisible,
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period for system_time (row_start, row_end)
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) with system versioning;
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insert into t1 values (1), (2);
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insert into t1 (row_start) select row_end from t1;
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ERROR HY000: The value specified for generated column 'row_start' in table 't1' has been ignored
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set sql_mode='';
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insert into t1 (row_start, row_end) values (DEFAULT, 1);
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Warnings:
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Warning 1906 The value specified for generated column 'row_end' in table 't1' has been ignored
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set sql_mode=default;
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select @@sql_mode into @saved_mode;
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set sql_mode= '';
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insert into t1 (x, row_start, row_end) values (3, 4, 5);
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Warnings:
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Warning 1906 The value specified for generated column 'row_start' in table 't1' has been ignored
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Warning 1906 The value specified for generated column 'row_end' in table 't1' has been ignored
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set sql_mode= @saved_mode;
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insert into t1 (row_start, row_end) values (DEFAULT, DEFAULT);
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select * from t1;
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x
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1
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2
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NULL
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3
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NULL
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# MDEV-14792 INSERT without column list into table with explicit versioning columns produces bad data
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create or replace table t1 (
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i int,
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s timestamp(6) as row start,
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e timestamp(6) as row end,
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c varchar(8),
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period for system_time(s, e))
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with system versioning;
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insert into t1 values (1, null, null, 'foo');
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select i, c, e>TIMESTAMP'2038-01-01 00:00:00' AS current_row from t1;
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i c current_row
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1 foo 1
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drop table t1;
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drop table t2;
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#
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# MDEV-14871 Server crashes in fill_record / fill_record_n_invoke_before_triggers upon inserting into versioned table with trigger
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#
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create or replace table t1 (pk int primary key) with system versioning;
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create trigger tr before insert on t1 for each row select 1 into @a;
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insert into t1 values (1),(2);
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drop table t1;
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