[MDEV-29666] InnoDB fails to purge secondary index records when indexed virtual columns exist - Jira

Details

Type: Bug
Status: Closed (View Workflow)
Priority: Critical
Resolution: Fixed
Affects Version/s: 10.2(EOL), 10.3(EOL), 10.4(EOL), 10.5, 10.6, 10.7(EOL), 10.8(EOL), 10.9(EOL), 10.10(EOL)
Fix Version/s: 10.3.37, 10.4.27, 10.5.18, 10.6.11, 10.7.7, 10.8.6, 10.9.4, 10.10.2, 10.11.1
Component/s: Storage Engine - InnoDB, Virtual Columns
Labels:
- leak
- purge

Description

When I tested ~~MDEV-24402~~ CHECK TABLE...EXTENDED, the test gcol.innodb_virtual_purge would fail because secondary indexes contain orphan records. Here is a reduced test case:

--source include/have_innodb.inc

CREATE TABLE t1 (a INT, b INT, a1 INT AS(a) VIRTUAL,

INDEX(a1),INDEX(b)) ENGINE=InnoDB;

INSERT INTO t1 SET a=1, b=1;

UPDATE t1 SET a=2, b=3;

let $datadir=`select @@datadir`;

let $sec=`select 3*@@innodb_page_size`;

SET GLOBAL innodb_fast_shutdown=0;

--source include/shutdown_mysqld.inc

--exec od -Ax -t x1 -j $sec $datadir/test/t1.ibd

--source include/start_mysqld.inc

DROP TABLE t1;

According to the od output, all history for the clustered index record (data fields starting at 0xc07e = 0xc063+0x001b) was purged. The fields are (DB_ROW_ID,DB_TRX_ID,DB_ROLL_PTR,a,b)=(0x200,0,1<<55,2,3):

10.3 ce23802c0e4c85018f2141d2ebb0602dc0d3d6d8
00c060 02 00 1b 69 6e 66 69 6d 75 6d 00 02 00 0b 00 00
00c070 73 75 70 72 65 6d 75 6d 00 00 00 10 ff f2 00 00
00c080 00 00 02 00 00 00 00 00 00 00 80 00 00 00 00 00
00c090 00 80 00 00 02 80 00 00 03 00 00 00 00 00 00 00

In the secondary indexes, the delete-marked records created by the UPDATE were not purged. Here is the entry for index(a1):

10.3 ce23802c0e4c85018f2141d2ebb0602dc0d3d6d8
010060 02 00 1b 69 6e 66 69 6d 75 6d 00 03 00 0b 00 00
010070 73 75 70 72 65 6d 75 6d 00 20 00 10 00 10 80 00
010080 00 01 00 00 00 00 02 00 00 00 00 18 ff e2 80 00
010090 00 02 00 00 00 00 02 00 00 00 00 00 00 00 00 00

We see both the delete-marked (a,DB_ROW_ID)=(1,0x200) at 0x1007e as well as the correct record (a,DB_ROW_ID)=2,0x200) at 0x1008e. There is a garbage record in index(b) as well:

10.3 ce23802c0e4c85018f2141d2ebb0602dc0d3d6d8
014060 02 00 1b 69 6e 66 69 6d 75 6d 00 03 00 0b 00 00
014070 73 75 70 72 65 6d 75 6d 00 20 00 10 00 10 80 00
014080 00 01 00 00 00 00 02 00 00 00 00 18 ff e2 80 00
014090 00 03 00 00 00 00 02 00 00 00 00 00 00 00 00 00

The delete-marked (b,DB_ROW_ID)=(1,0x200) at 0x1e07e should have been purged. Only the record (b,DB_ROW_ID)=(3,0x200) should be there.

I tracked this down to the following code in the function row_purge_upd_exist_or_extern_func():

		if (row_upd_changes_ord_field_binary(node->index, node->update,

						     thr, NULL, NULL)) {

			/* Build the older version of the index entry */

			dtuple_t*	entry = row_build_index_entry_low(

				node->row, NULL, node->index,

				heap, ROW_BUILD_FOR_PURGE);

			row_purge_remove_sec_if_poss(node, node->index, entry);

We end up with entry=nullptr for both indexes, because node->row is invalid or being accessed incorrectly. The pointer to data_error indicates a column that has not been fully initialized:

10.3 ce23802c0e4c85018f2141d2ebb0602dc0d3d6d8
Thread 22 hit Breakpoint 2, row_purge_remove_sec_if_poss (node=node@entry=0x5613c42f37a0, index=0x7f8414167a50, entry=0x0) at /mariadb/10.3/storage/innobase/row/row0purge.cc:688
688 if (!entry) {
1: node.table.name = {m_name = 0x7f8414158690 "test/t1"}
(rr) p *node.row
$1 = {info_bits = 0, n_fields = 5, n_fields_cmp = 5, fields = 0x7f841c009270,
n_v_fields = 1, v_fields = 0x7f841c0092e8, magic_n = 65478679}
(rr) p *node.row.fields@5
$2 = {{data = 0x5613c42f3d5d, ext = 0, spatial_status = 0, len = 4, type = {
prtype = 1027, mtype = 6, len = 4, mbminlen = 0, mbmaxlen = 0}}, {
data = 0x5613c42f3d63, ext = 0, spatial_status = 0, len = 4, type = {
prtype = 1027, mtype = 6, len = 4, mbminlen = 0, mbmaxlen = 0}}, {
data = 0x5613c3518908 <data_error>, ext = 0, spatial_status = 0,
len = 4294967295, type = {prtype = 111, mtype = 0, len = 0, mbminlen = 0,
mbmaxlen = 0}}, {data = 0x7f841c009210, ext = 0, spatial_status = 0,
len = 6, type = {prtype = 257, mtype = 8, len = 6, mbminlen = 0,
mbmaxlen = 0}}, {data = 0x7f841c009218, ext = 0, spatial_status = 0,
len = 7, type = {prtype = 258, mtype = 8, len = 7, mbminlen = 0,
mbmaxlen = 0}}}

Attachments

Issue Links

causes

MDEV-30024 InnoDB: tried to purge non-delete-marked record of an index on a virtual column prefix

Closed

is caused by

MDEV-5800 indexes on virtual (not materialized) columns

Closed

relates to

MDEV-22363 Reimplement the InnoDB virtual column code

Open

MDEV-29823 Secondary index records may never be purged after rollback

Confirmed

MDEV-14051 'Undo log record is too big.' error occurring in very narrow range of string lengths

Closed

MDEV-14799 After UPDATE of indexed columns, old values will not be purged from secondary indexes

Closed

MDEV-20640 [ERROR] InnoDB: tried to purge non-delete-marked record and Assertion `0' failed in row_purge_remove_sec_if_poss_leaf

Closed

MDEV-24402 CHECK TABLE may miss some cases of index inconsistencies

Closed

(3 relates to)

Activity

Ascending order - Click to sort in descending order

Marko Mäkelä added a comment - 2022-09-29 11:01

As far as I can tell, the problem was caused by the unnecessary and problematic separation of virtual and regular columns in MySQL 5.7.8. The function trx_undo_rec_get_partial_row() will leave a gap in the table row tuple, and instead copy the value of the indexed virtual column a1=1 from the undo log record to a separate array:

		if (is_virtual) {

			dict_v_col_t* vcol = dict_table_get_nth_v_col(

						index->table, field_no);

			col = &vcol->m_col;

			col_no = dict_col_get_no(col);

			dfield = dtuple_get_nth_v_field(*row, vcol->v_pos);

			dict_col_copy_type(

				&vcol->m_col,

				dfield_get_type(dfield));

		} else {

…

		dfield_set_data(dfield, field, len);

After the MDEV-22363 cleanup, we would just allocate a table row tuple containing all the columns in the same order as TABLE_SHARE::field, including any virtual columns.

Some insult to injury is being added in row_build_index_entry_low():

		if (col->is_virtual()) {

			const dict_v_col_t*	v_col

				= reinterpret_cast<const dict_v_col_t*>(col);

			ut_ad(v_col->v_pos < dtuple_get_n_v_fields(row));

			dfield2 = dtuple_get_nth_v_field(row, v_col->v_pos);

			ut_ad(dfield_is_null(dfield2) ||

			      dfield_get_len(dfield2) == 0 || dfield2->data);

		} else {

			dfield2 = dtuple_get_nth_field(row, col_no);

			ut_ad(dfield_get_type(dfield2)->mtype == DATA_MISSING

			      || (!(dfield_get_type(dfield2)->prtype

				    & DATA_VIRTUAL)));

		if (UNIV_UNLIKELY(dfield_get_type(dfield2)->mtype

				  == DATA_MISSING)) {

			/* The field has not been initialized in the row.

			This should be from trx_undo_rec_get_partial_row(). */

			return(NULL);

The assertion in the else branch had been relaxed in MySQL 5.7.9, with no analysis, explanation or test case, or identification of the failing assertion.

The column that we fail to find in the clustered index row tuple is very much present in the undo log record, because it is the primary key GEN_CLUST_INDEX(DB_ROW_ID):

10.3 ce23802c0e4c85018f2141d2ebb0602dc0d3d6d8
Thread 3 hit Hardware access (read/write) watchpoint 7: (dfield_t ) 0x7f841c0092a0

Value = {data = 0x5613c3518908 <data_error>, ext = 0, spatial_status = 0, len = 4294967295, type = {prtype = 111, mtype = 0, len = 0, mbminlen = 0, mbmaxlen = 0}}
0x00005613c30e496b in row_build_index_entry_low (row=0x7f841c009238, ext=ext@entry=0x0, index=0x7f8414168110, heap=heap@entry=0x7f841c00aff0, flag=flag@entry=1) at /mariadb/10.3/storage/innobase/row/row0row.cc:259
259 ut_ad(dfield_get_type(dfield2)->mtype == DATA_MISSING
(rr) p *ind_field
$25 = {col = 0x7f841400ca20, name = {m_name = 0x7f841400cb2c "DB_ROW_ID"}, prefix_len = 0, fixed_len = 6}

Marko Mäkelä added a comment - 2022-09-29 11:01 As far as I can tell, the problem was caused by the unnecessary and problematic separation of virtual and regular columns in MySQL 5.7.8 . The function trx_undo_rec_get_partial_row() will leave a gap in the table row tuple, and instead copy the value of the indexed virtual column a1=1 from the undo log record to a separate array: if (is_virtual) { dict_v_col_t* vcol = dict_table_get_nth_v_col( index->table, field_no); col = &vcol->m_col; col_no = dict_col_get_no(col); dfield = dtuple_get_nth_v_field(*row, vcol->v_pos); dict_col_copy_type( &vcol->m_col, dfield_get_type(dfield)); } else { … } dfield_set_data(dfield, field, len); After the MDEV-22363 cleanup, we would just allocate a table row tuple containing all the columns in the same order as TABLE_SHARE::field , including any virtual columns. Some insult to injury is being added in row_build_index_entry_low() : if (col->is_virtual()) { const dict_v_col_t* v_col = reinterpret_cast < const dict_v_col_t*>(col); ut_ad(v_col->v_pos < dtuple_get_n_v_fields(row)); dfield2 = dtuple_get_nth_v_field(row, v_col->v_pos); ut_ad(dfield_is_null(dfield2) || dfield_get_len(dfield2) == 0 || dfield2->data); } else { dfield2 = dtuple_get_nth_field(row, col_no); ut_ad(dfield_get_type(dfield2)->mtype == DATA_MISSING || (!(dfield_get_type(dfield2)->prtype & DATA_VIRTUAL))); } if (UNIV_UNLIKELY(dfield_get_type(dfield2)->mtype == DATA_MISSING)) { /* The field has not been initialized in the row. This should be from trx_undo_rec_get_partial_row(). */ return (NULL); } The assertion in the else branch had been relaxed in MySQL 5.7.9 , with no analysis, explanation or test case, or identification of the failing assertion. The column that we fail to find in the clustered index row tuple is very much present in the undo log record, because it is the primary key GEN_CLUST_INDEX(DB_ROW_ID) : 10.3 ce23802c0e4c85018f2141d2ebb0602dc0d3d6d8 Thread 3 hit Hardware access (read/write) watchpoint 7: *(dfield_t *) 0x7f841c0092a0 Value = {data = 0x5613c3518908 <data_error>, ext = 0, spatial_status = 0, len = 4294967295, type = {prtype = 111, mtype = 0, len = 0, mbminlen = 0, mbmaxlen = 0}} 0x00005613c30e496b in row_build_index_entry_low (row=0x7f841c009238, ext=ext@entry=0x0, index=0x7f8414168110, heap=heap@entry=0x7f841c00aff0, flag=flag@entry=1) at /mariadb/10.3/storage/innobase/row/row0row.cc:259 259 ut_ad(dfield_get_type(dfield2)->mtype == DATA_MISSING (rr) p *ind_field $25 = {col = 0x7f841400ca20, name = {m_name = 0x7f841400cb2c "DB_ROW_ID"}, prefix_len = 0, fixed_len = 6}

Marko Mäkelä added a comment - 2022-09-29 12:37

In the split encoding of the table row tuple, row_build_index_entry_low() should have the persistent columns of the table in row->fields, indexed by the column position (as if no virtual columns existed), and the virtual columns in row->v_fields. That is, row->fields should contain the value of (a,b,DB_ROW_ID,DB_TRX_ID,DB_ROLL_PTR) and row->v_fields the value of (a1).

This error affects all secondary indexes because the value of the hidden primary key column DB_ROW_ID is missing.

If the UPDATE statement is changed to UPDATE t1 SET b=3 (no change to the indexed virtual column), then trx_undo_rec_get_partial_row() will be invoked with the following:

10.3 ce23802c0e4c85018f2141d2ebb0602dc0d3d6d8
#0 trx_undo_rec_get_partial_row (ptr=ptr@entry=0x55efec4809d1 "", index=index@entry=0x7f599800d850, update=0x7f59940090f0, row=row@entry=0x55efec480498, ignore_prefix=0, heap=0x55efec480920)
at /mariadb/10.3/storage/innobase/trx/trx0rec.cc:1681
1681 {
(rr) p *update
$1 = {heap = 0x55efec480920, info_bits = 0, old_vrow = 0x0, n_fields = 3, fields = 0x7f5994009120, vers_sys_value = "\000\000\000\000\000\000\000"}
(rr) p *update.fields@update.n_fields
$2 = {{field_no = 4, orig_len = 0, exp = 0x0, new_val = {data = 0x55efec4809cd, ext = 0, spatial_status = 0, len = 4, type = {prtype = 1027, mtype = 6, len = 4, mbminlen = 0, mbmaxlen = 0}}, old_v_val = 0x0}, {
field_no = 1, orig_len = 0, exp = 0x0, new_val = {data = 0x7f59940091b0, ext = 0, spatial_status = 0, len = 6, type = {prtype = 257, mtype = 8, len = 6, mbminlen = 0, mbmaxlen = 0}}, old_v_val = 0x0}, {
field_no = 2, orig_len = 0, exp = 0x0, new_val = {data = 0x7f59940091b8, ext = 0, spatial_status = 0, len = 7, type = {prtype = 258, mtype = 8, len = 7, mbminlen = 0, mbmaxlen = 0}}, old_v_val = 0x0}}
(rr) p *index.fields@index.n_fields
$3 = {{col = 0x7f599800ca20, name = {m_name = 0x7f599800cb2c "DB_ROW_ID"}, prefix_len = 0, fixed_len = 6}, {col = 0x7f599800ca40, name = {m_name = 0x7f599800cb36 "DB_TRX_ID"}, prefix_len = 0, fixed_len = 6}, {
col = 0x7f599800ca60, name = {m_name = 0x7f599800cb40 "DB_ROLL_PTR"}, prefix_len = 0, fixed_len = 7}, {col = 0x7f599800c9e0, name = {m_name = 0x7f599800cb28 "a"}, prefix_len = 0, fixed_len = 4}, {
col = 0x7f599800ca00, name = {m_name = 0x7f599800cb2a "b"}, prefix_len = 0, fixed_len = 4}}
(rr) p/x *ptr@100
$4 = {0x0, 0x17, 0x0, 0x6, 0x0, 0x0, 0x0, 0x0, 0x2, 0x0, 0x83, 0xff, 0xf1, 0x0, 0x5, 0x1, 0x1a, 0x0, 0x4, 0x80, 0x0, 0x0, 0x1, 0x2, 0xc3, 0x48, 0xec, 0xef, 0x55, 0x0, 0x0, 0x5a, 0xb6, 0x1c, 0xeb, 0xef, 0x55,
0x0, 0x0, 0xf3, 0xa8, 0x1c, 0xeb, 0xef, 0x55, 0x0, 0x0, 0x83, 0xc0, 0x1c, 0xeb, 0xef, 0x55, 0x0, 0x0, 0x20, 0x9, 0x48, 0xec, 0xef, 0x55, 0x0, 0x0, 0xf0, 0x9, 0x48, 0xec, 0xef, 0x55, 0x0, 0x0, 0xb0, 0x4f,
0xa, 0x98, 0x59, 0x7f, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2c, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x10, 0x0, 0x0, 0x0, 0x0}

The hidden primary key column DB_ROW_ID at field_no=0 is not affected by the update, but its value will be read by trx_undo_rec_get_col_val() from ptr+3 that was passed to trx_undo_rec_get_partial_row() and correctly stored to the row tuple. The primary key was also already parsed and stored in purge_node_t::ref by the caller.

In the case of UPDATE t1 SET a=2, b=3, the ptr that is passed to trx_undo_rec_get_partial_row() will look different:

10.3 ce23802c0e4c85018f2141d2ebb0602dc0d3d6d8
Thread 3 hit Breakpoint 1, trx_undo_rec_get_partial_row (ptr=ptr@entry=0x557248fc29e9 "", index=index@entry=0x7f21bc00d850, update=0x7f21c40090f0, row=row@entry=0x557248fc2498, ignore_prefix=0, heap=0x557248fc2920) at /mariadb/10.3/storage/innobase/trx/trx0rec.cc:1681
1681 {
(rr) p/x *ptr@100
$1 = {0x0, 0xf, 0x83, 0xff, 0xf1, 0x0, 0x5, 0x1, 0x1a, 0x0, 0x4, 0x80, 0x0, 0x0, 0x1, 0x2, 0xc3, 0xa, 0xbc, 0x21, 0x7f, 0x0, 0x0, 0x5a, 0x46, 0x76, 0x47, 0x72, 0x55, 0x0, 0x0, 0xf3, 0x38, 0x76, 0x47, 0x72,
0x55, 0x0, 0x0, 0x83, 0x50, 0x76, 0x47, 0x72, 0x55, 0x0, 0x0, 0x20, 0x29, 0xfc, 0x48, 0x72, 0x55, 0x0, 0x0, 0x0, 0x2a, 0xfc, 0x48, 0x72, 0x55, 0x0, 0x0, 0xb0, 0x4f, 0xa, 0xbc, 0x21, 0x7f, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2c, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x10, 0x0 <repeats 12 times>}

The record for the DB_ROW_ID=0x200 is completely missing.

Even if I add an explicit primary key, the outcome is the same:

--source include/have_innodb.inc

CREATE TABLE t1 (pk INT PRIMARY KEY, a INT, b INT, a1 INT AS(a) VIRTUAL,

INDEX(a1),INDEX(b)) ENGINE=InnoDB;

INSERT INTO t1 SET pk=1, a=1, b=1;

UPDATE t1 SET a=2, b=3;

let $datadir=`select @@datadir`;

let $sec=`select 3*@@innodb_page_size`;

SET GLOBAL innodb_fast_shutdown=0;

--source include/shutdown_mysqld.inc

--exec od -Ax -t x1 -j $sec $datadir/test/t1.ibd

--source include/start_mysqld.inc

DROP TABLE t1;

10.3 ce23802c0e4c85018f2141d2ebb0602dc0d3d6d8
014060 02 00 1b 69 6e 66 69 6d 75 6d 00 03 00 0b 00 00
014070 73 75 70 72 65 6d 75 6d 00 20 00 10 00 0e 80 00
014080 00 01 80 00 00 01 00 00 00 18 ff e4 80 00 00 03
014090 80 00 00 01 00 00 00 00 00 00 00 00 00 00 00 00

Here, we will have two records in the index: a delete-marked (1,1) that should have been purged, and the correct record (b,pk)=(3,1).

This bug reminds me of ~~MDEV-14799~~. If I revert both that fix and the optimization ~~MDEV-14051~~ that caused it, then the index record will be purged correctly. It looks like the optimization must be adapted for indexed virtual columns.

Marko Mäkelä added a comment - 2022-09-29 12:37 In the split encoding of the table row tuple, row_build_index_entry_low() should have the persistent columns of the table in row->fields , indexed by the column position (as if no virtual columns existed), and the virtual columns in row->v_fields . That is, row->fields should contain the value of (a,b,DB_ROW_ID,DB_TRX_ID,DB_ROLL_PTR) and row->v_fields the value of (a1). This error affects all secondary indexes because the value of the hidden primary key column DB_ROW_ID is missing. If the UPDATE statement is changed to UPDATE t1 SET b=3 (no change to the indexed virtual column), then trx_undo_rec_get_partial_row() will be invoked with the following: 10.3 ce23802c0e4c85018f2141d2ebb0602dc0d3d6d8 #0 trx_undo_rec_get_partial_row (ptr=ptr@entry=0x55efec4809d1 "", index=index@entry=0x7f599800d850, update=0x7f59940090f0, row=row@entry=0x55efec480498, ignore_prefix=0, heap=0x55efec480920) at /mariadb/10.3/storage/innobase/trx/trx0rec.cc:1681 1681 { (rr) p *update $1 = {heap = 0x55efec480920, info_bits = 0, old_vrow = 0x0, n_fields = 3, fields = 0x7f5994009120, vers_sys_value = "\000\000\000\000\000\000\000"} (rr) p *update.fields@update.n_fields $2 = {{field_no = 4, orig_len = 0, exp = 0x0, new_val = {data = 0x55efec4809cd, ext = 0, spatial_status = 0, len = 4, type = {prtype = 1027, mtype = 6, len = 4, mbminlen = 0, mbmaxlen = 0}}, old_v_val = 0x0}, { field_no = 1, orig_len = 0, exp = 0x0, new_val = {data = 0x7f59940091b0, ext = 0, spatial_status = 0, len = 6, type = {prtype = 257, mtype = 8, len = 6, mbminlen = 0, mbmaxlen = 0}}, old_v_val = 0x0}, { field_no = 2, orig_len = 0, exp = 0x0, new_val = {data = 0x7f59940091b8, ext = 0, spatial_status = 0, len = 7, type = {prtype = 258, mtype = 8, len = 7, mbminlen = 0, mbmaxlen = 0}}, old_v_val = 0x0}} (rr) p *index.fields@index.n_fields $3 = {{col = 0x7f599800ca20, name = {m_name = 0x7f599800cb2c "DB_ROW_ID"}, prefix_len = 0, fixed_len = 6}, {col = 0x7f599800ca40, name = {m_name = 0x7f599800cb36 "DB_TRX_ID"}, prefix_len = 0, fixed_len = 6}, { col = 0x7f599800ca60, name = {m_name = 0x7f599800cb40 "DB_ROLL_PTR"}, prefix_len = 0, fixed_len = 7}, {col = 0x7f599800c9e0, name = {m_name = 0x7f599800cb28 "a"}, prefix_len = 0, fixed_len = 4}, { col = 0x7f599800ca00, name = {m_name = 0x7f599800cb2a "b"}, prefix_len = 0, fixed_len = 4}} (rr) p/x *ptr@100 $4 = {0x0, 0x17, 0x0, 0x6, 0x0, 0x0, 0x0, 0x0, 0x2, 0x0, 0x83, 0xff, 0xf1, 0x0, 0x5, 0x1, 0x1a, 0x0, 0x4, 0x80, 0x0, 0x0, 0x1, 0x2, 0xc3, 0x48, 0xec, 0xef, 0x55, 0x0, 0x0, 0x5a, 0xb6, 0x1c, 0xeb, 0xef, 0x55, 0x0, 0x0, 0xf3, 0xa8, 0x1c, 0xeb, 0xef, 0x55, 0x0, 0x0, 0x83, 0xc0, 0x1c, 0xeb, 0xef, 0x55, 0x0, 0x0, 0x20, 0x9, 0x48, 0xec, 0xef, 0x55, 0x0, 0x0, 0xf0, 0x9, 0x48, 0xec, 0xef, 0x55, 0x0, 0x0, 0xb0, 0x4f, 0xa, 0x98, 0x59, 0x7f, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2c, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x10, 0x0, 0x0, 0x0, 0x0} The hidden primary key column DB_ROW_ID at field_no=0 is not affected by the update, but its value will be read by trx_undo_rec_get_col_val() from ptr+3 that was passed to trx_undo_rec_get_partial_row() and correctly stored to the row tuple. The primary key was also already parsed and stored in purge_node_t::ref by the caller. In the case of UPDATE t1 SET a=2, b=3 , the ptr that is passed to trx_undo_rec_get_partial_row() will look different: 10.3 ce23802c0e4c85018f2141d2ebb0602dc0d3d6d8 Thread 3 hit Breakpoint 1, trx_undo_rec_get_partial_row (ptr=ptr@entry=0x557248fc29e9 "", index=index@entry=0x7f21bc00d850, update=0x7f21c40090f0, row=row@entry=0x557248fc2498, ignore_prefix=0, heap=0x557248fc2920) at /mariadb/10.3/storage/innobase/trx/trx0rec.cc:1681 1681 { (rr) p/x *ptr@100 $1 = {0x0, 0xf, 0x83, 0xff, 0xf1, 0x0, 0x5, 0x1, 0x1a, 0x0, 0x4, 0x80, 0x0, 0x0, 0x1, 0x2, 0xc3, 0xa, 0xbc, 0x21, 0x7f, 0x0, 0x0, 0x5a, 0x46, 0x76, 0x47, 0x72, 0x55, 0x0, 0x0, 0xf3, 0x38, 0x76, 0x47, 0x72, 0x55, 0x0, 0x0, 0x83, 0x50, 0x76, 0x47, 0x72, 0x55, 0x0, 0x0, 0x20, 0x29, 0xfc, 0x48, 0x72, 0x55, 0x0, 0x0, 0x0, 0x2a, 0xfc, 0x48, 0x72, 0x55, 0x0, 0x0, 0xb0, 0x4f, 0xa, 0xbc, 0x21, 0x7f, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2c, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x10, 0x0 <repeats 12 times>} The record for the DB_ROW_ID=0x200 is completely missing. Even if I add an explicit primary key, the outcome is the same: --source include/have_innodb.inc CREATE TABLE t1 (pk INT PRIMARY KEY , a INT , b INT , a1 INT AS (a) VIRTUAL, INDEX (a1), INDEX (b)) ENGINE=InnoDB; INSERT INTO t1 SET pk=1, a=1, b=1; UPDATE t1 SET a=2, b=3; let $datadir=` select @@datadir`; let $sec=` select 3*@@innodb_page_size`; SET GLOBAL innodb_fast_shutdown=0; --source include/shutdown_mysqld.inc --exec od -Ax -t x1 -j $sec $datadir/test/t1.ibd --source include/start_mysqld.inc DROP TABLE t1; 10.3 ce23802c0e4c85018f2141d2ebb0602dc0d3d6d8 014060 02 00 1b 69 6e 66 69 6d 75 6d 00 03 00 0b 00 00 014070 73 75 70 72 65 6d 75 6d 00 20 00 10 00 0e 80 00 014080 00 01 80 00 00 01 00 00 00 18 ff e4 80 00 00 03 014090 80 00 00 01 00 00 00 00 00 00 00 00 00 00 00 00 Here, we will have two records in the index: a delete-marked (1,1) that should have been purged, and the correct record (b,pk)=(3,1). This bug reminds me of MDEV-14799 . If I revert both that fix and the optimization MDEV-14051 that caused it, then the index record will be purged correctly. It looks like the optimization must be adapted for indexed virtual columns.

People

Assignee:: Marko Mäkelä

Reporter:: Marko Mäkelä

Votes:: 0 Vote for this issue

Watchers:: 3 Start watching this issue

Dates

Created:: 2022-09-29 09:57

Updated:: 2023-12-06 20:06

Resolved:: 2022-10-05 18:05

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