In collaboration with Sergey Vojtovich <svoj@mariadb.org>
The COMPRESSED clause is now a part of the data type and goes immediately
after the data type and length, but before the CHARACTER SET clause,
and before column attributes such as DEFAULT, COLLATE, ON UPDATE,
SYSTEM VERSIONING, engine specific column attributes.
In the old reduction, the COMPRESSED clause was a column attribute.
New syntax:
<varchar or text data type> <length> <compression> <character set> <column attributes>
<varbinary or blob data type> <length> <compression> <column attributes>
New syntax examples:
VARCHAR(1000) COMPRESSED CHARACTER SET latin1 DEFAULT ''
BLOB COMPRESSED DEFAULT ''
Deprecate syntax examples:
VARCHAR(1000) CHARACTER SET latin1 COMPRESSED DEFAULT ''
TEXT CHARACTER SET latin1 DEFAULT '' COMPRESSED
VARBINARY(1000) DEFAULT '' COMPRESSED
As a side effect:
- COMPRESSED is not valid as an SP label name in SQL/PSM routines any more
(but it's still valid as an SP label name in sql_mode=ORACLE)
- COMPRESSED is now allowed in combination with GENERATED ALWAYS AS:
TEXT COMPRESSED GENERATED ALWAYS AS REPEAT('a',1000)
Field_bit for BIT(20) uses 2 full bytes in the record,
with additional 4 uneven bits in the "null bit area".
Field::set_default() called from Field_bit::set_default() erroneously
copied 3 bytes instead of 2 bytes from the record with default values.
Changing Field::set_default() to copy pack_length_in_rec() bytes
instead of pack_length() bytes.
If we have a 2+ node cluster which is replicating from an async master
and the binlog_format is set to STATEMENT and multi-row inserts are executed
on a table with an auto_increment column such that values are automatically
generated by MySQL, then the server node generates wrong auto_increment
values, which are different from what was generated on the async master.
In the title of the MDEV-9519 it was proposed to ban start slave on a Galera
if master binlog_format = statement and wsrep_auto_increment_control = 1,
but the problem can be solved without such a restriction.
The causes and fixes:
1. We need to improve processing of changing the auto-increment values
after changing the cluster size.
2. If wsrep auto_increment_control switched on during operation of
the node, then we should immediately update the auto_increment_increment
and auto_increment_offset global variables, without waiting of the next
invocation of the wsrep_view_handler_cb() callback. In the current version
these variables retain its initial values if wsrep_auto_increment_control
is switched on during operation of the node, which leads to inconsistent
results on the different nodes in some scenarios.
3. If wsrep auto_increment_control switched off during operation of the node,
then we must return the original values of the auto_increment_increment and
auto_increment_offset global variables, as the user has set. To make this
possible, we need to add a "shadow copies" of these variables (which stores
the latest values set by the user).
https://jira.mariadb.org/browse/MDEV-9519
If we have a 2+ node cluster which is replicating from an async master
and the binlog_format is set to STATEMENT and multi-row inserts are executed
on a table with an auto_increment column such that values are automatically
generated by MySQL, then the server node generates wrong auto_increment
values, which are different from what was generated on the async master.
In the title of the MDEV-9519 it was proposed to ban start slave on a Galera
if master binlog_format = statement and wsrep_auto_increment_control = 1,
but the problem can be solved without such a restriction.
The causes and fixes:
1. We need to improve processing of changing the auto-increment values
after changing the cluster size.
2. If wsrep auto_increment_control switched on during operation of
the node, then we should immediately update the auto_increment_increment
and auto_increment_offset global variables, without waiting of the next
invocation of the wsrep_view_handler_cb() callback. In the current version
these variables retain its initial values if wsrep_auto_increment_control
is switched on during operation of the node, which leads to inconsistent
results on the different nodes in some scenarios.
3. If wsrep auto_increment_control switched off during operation of the node,
then we must return the original values of the auto_increment_increment and
auto_increment_offset global variables, as the user has set. To make this
possible, we need to add a "shadow copies" of these variables (which stores
the latest values set by the user).
https://jira.mariadb.org/browse/MDEV-9519
If we have a 2+ node cluster which is replicating from an async master
and the binlog_format is set to STATEMENT and multi-row inserts are executed
on a table with an auto_increment column such that values are automatically
generated by MySQL, then the server node generates wrong auto_increment
values, which are different from what was generated on the async master.
In the title of the MDEV-9519 it was proposed to ban start slave on a Galera
if master binlog_format = statement and wsrep_auto_increment_control = 1,
but the problem can be solved without such a restriction.
The causes and fixes:
1. We need to improve processing of changing the auto-increment values
after changing the cluster size.
2. If wsrep auto_increment_control switched on during operation of
the node, then we should immediately update the auto_increment_increment
and auto_increment_offset global variables, without waiting of the next
invocation of the wsrep_view_handler_cb() callback. In the current version
these variables retain its initial values if wsrep_auto_increment_control
is switched on during operation of the node, which leads to inconsistent
results on the different nodes in some scenarios.
3. If wsrep auto_increment_control switched off during operation of the node,
then we must return the original values of the auto_increment_increment and
auto_increment_offset global variables, as the user has set. To make this
possible, we need to add a "shadow copies" of these variables (which stores
the latest values set by the user).
https://jira.mariadb.org/browse/MDEV-9519
- clean up DEFAULT() to work only with default value and correctly print
itself.
- fix of DBUG_ASSERT about fields read/write
- fix of field marking for write based really on the thd->mark_used_columns flag
If we have a 2+ node cluster which is replicating from an async master
and the binlog_format is set to STATEMENT and multi-row inserts are executed
on a table with an auto_increment column such that values are automatically
generated by MySQL, then the server node generates wrong auto_increment
values, which are different from what was generated on the async master.
The causes and fixes:
1. We need to improve processing of changing the auto-increment values
after changing the cluster size.
2. If wsrep auto_increment_control switched on during operation of
the node, then we should immediately update the auto_increment_increment
and auto_increment_offset global variables, without waiting of the next
invocation of the wsrep_view_handler_cb() callback. In the current version
these variables retain its initial values if wsrep_auto_increment_control
is switched on during operation of the node, which leads to inconsistent
results on the different nodes in some scenarios.
3. If wsrep auto_increment_control switched off during operation of the node,
then we must return the original values of the auto_increment_increment and
auto_increment_offset global variables, as the user has set. To make this
possible, we need to add a "shadow copies" of these variables (which stores
the latest values set by the user).
NULL values when there is no DEFAULT
Copy and inplace algorithm works similarly for
NULL to NOT NULL conversion for the following cases:
(1) strict sql mode - Should give error.
(2) non-strict sql mode - Should give warnings alone
(3) alter ignore table command. - Should give warnings alone.
The bug was that innobase_get_computed_value() trashed record[0] and data
in Field_blob::value
Fixed by using a record on the heap for innobase_get_computed_value()
Reviewer: Marko Mäkelä
When altering from DECIMAL to *INT UNIGNED or to BIT, go through val_decimal(),
to avoid truncation to the biggest possible signed integer
(0x7FFFFFFFFFFFFFFF / 9223372036854775807).
Compressed blob columns didn't accept data at their capacity. E.g. storing
255 bytes to TINYBLOB results in "Data too long" error.
Now it is allowed assuming compression method was able to produce shorter
string (so that both metadata and compressed data fits blob) and
column_compression_threshold is lower than blob.
If no compression was performed, we still have to reserve additional byte
for metadata and thus we perform normal data truncation and return it's
status.
Unexpected data truncation may occur when storing data to compressed blob
column having multi byte variable length character sets.
The reason was incorrect number of characters limit was enforced for
blobs.
Modern compilers (such as GCC 8) emit warnings that the
'register' keyword is deprecated and not valid C++17.
Let us remove most use of the 'register' keyword.
Code in 'extra/' is not touched.
This patch does the following:
1. Makes Field_vers_trx_id::type_handler() return
&type_handler_vers_trx_id rather than &type_handler_longlong.
Fixes Item_func::convert_const_compared_to_int_field() to
test field_item->type_handler() against &type_handler_vers_trx_id,
instead of testing field_item->vers_trx_id().
2. Removes VERS_TRX_ID related code from
Type_handler_hybrid_field_type::aggregate_for_comparison(),
because "BIGINT UNSIGNED GENERATED ALWAYS AS ROW {START|END}"
columns behave just like a BIGINT in a regular comparison,
i.e. when not inside AS OF.
3. Removes
- Type_handler_hybrid_field_type::m_vers_trx_id;
- Type_handler_hybrid_field_type::m_flags;
because a "BIGINT UNSIGNED GENERATED ALWAYS AS ROW {START|END}"
behaves like a regular BIGINT column when in UNION.
4. Removes Field::vers_trx_id(), Item::vers_trx_id(), Item::field_flags()
They are not needed anymore. See N1.
Problems:
1. Unlike Item_field::fix_fields(),
Item_sum_sp::fix_length_and_dec() and Item_func_sp::fix_length_and_dec()
did not run the code which resided in adjust_max_effective_column_length(),
therefore they did not extend max_length for the integer return data types
from the user-specified length to the maximum length according to
the data type capacity.
2. The code in adjust_max_effective_column_length() was not correct
for TEXT data, because Field_blob::max_display_length()
multiplies to mbmaxlen. So TEXT variants were unintentionally
promoted to the next longer data type for multi-byte character
sets: TINYTEXT->TEXT, TEXT->MEDIUMTEXT, MEDIUMTEXT->LONGTEXT.
3. Item_sum_sp::create_table_field_from_handler()
Item_func_sp::create_table_field_from_handler()
erroneously called tmp_table_field_from_field_type(),
which converted VARCHAR(>512) to TEXT variants.
So "CREATE..SELECT spfunc()" erroneously converted
VARCHAR to TEXT. This was wrong, because stored
functions have explicitly declared data types,
which should be preserved.
Solution:
- Removing Type_std_attributes(const Field *)
and using instead Type_std_attributes::set() in combination
with field->type_str_attributes() all around the code, e.g.:
Type_std_attributes::set(field->type_std_attributes())
These two ways of copying attributes from a Field
to an Item duplicated each other, and were slightly
different in how to mix max_length and mbmaxlen.
- Removing adjust_max_effective_column_length() and
fixing Field::type_std_attributes() to do all necessary
type-specific calculations , so no further adjustments
is needed.
Field::type_std_attributes() is now called from all affected methods:
Item_field::fix_fields()
Item_sum_sp::fix_length_and_dec()
Item_func_sp::fix_length_and_dec()
This fixes the problem N1.
- Making Field::type_std_attributes() virtual, to make
sure that type-specific adjustments a properly done
by individual Field_xxx classes. Implementing
Field_blob::type_std_attributes() in the way that
no TEXT promotion is done.
This fixes the problem N2.
- Fixing Item_sum_sp::create_table_field_from_handler()
Item_func_sp::create_table_field_from_handler() to
call create_table_field_from_handler() instead of
tmp_table_field_from_field_type() to avoid
VARCHAR->TEXT conversion on "CREATE..SELECT spfunc()".
- Recording mysql-test/suite/compat/oracle/r/sp-param.result
as "CREATE..SELECT spfunc()" now correctly
preserve the data type as specified in the RETURNS clause.
- Adding new tests
Problem:
The logic in store_column_type() with a switch on field type was
hard to follow. The part for MEDIUMINT (MYSQL_TYPE_INT24) was not correct.
It erroneously calculated the precision of MEDIUMINT UNSIGNED
as 7 instead of 8.
A similar hard-to-follow switch doing some type specific calculations
resided in adjust_max_effective_column_length(). It was also wrong for
MEDIUMINT (reported as a separate issue in MDEV-15946).
Solution:
1. Introducing a new class Information_schema_numeric_attributes
2. Adding a new virtual method Field::information_schema_numeric_attributes()
3. Splitting the logic in store_column_type() into virtual
implementations of information_schema_numeric_attributes().
4. In order to avoid adding duplicate code for the integer data types,
adding a new virtual method Field_int::numeric_precision(),
which returns the number of digits.
Additional changes:
1. Adding the "const" qualifier to Field::max_display_length()
2. Moving the code from adjust_max_effective_column_length()
directly to Field::max_display_length().
There was no any sense to have two implementations:
- a set of wrong virtual implementations for Field_xxx::max_display_length()
- additional code in adjust_max_effective_column_length() fixing
bad results of Field_xxx::max_display_length()
This change is safe:
- The code using Field::max_display_length()
in field.cc, sql_show.cc, sql_type.cc is not affected.
- The code in rpl_utility.cc is also not affected.
See a new DBUG_ASSSERT and new comments explaining why.
In the new reduction, Field_xxx::max_display_length() returns
correct results for all integer types (except MEDIUMINT, see below).
Putting implementations of numeric_precision() and max_display_length()
near each other in field.h made the logic much clearer and thus
helped to reveal bad results for Field_medium::max_display_length(),
which returns 9 instead of 8 for signed MEDIUMINT fields.
This problem will be addressed separately (MDEV-15946).
Note, this change is also useful for pluggable data types (see MDEV-4912),
as now a user defined Field_xxx has a way to control what's returned
in INFORMATION_SCHEMA.COLUMNS.NUMERIC_PRECISION and
INFORMATION_SCHEMA.COLUMNS.NUMERIC_SCALE by implementing
a desired behavior in Field_xxx::information_schema_numeric_attributes().
Renaming methods:
- Field::make_field(Send_field*) to make_send_field(..)
- Item::make_field(THD *,Send_field *) to make_send_field(..)
- Item::init_make_field(Send_field *, enum_field_type) to init_make_send_field(..)
These names looked similar to other functions that are used
for a very different purpose (creating Field instances):
- Public function "Field * make_field(..)"
- Method "Field *Column_defitinion::make_field(..)"
The rename makes it's easier to search the code using "grep".
- Adding class Field_int as a common
parent for Field_{longlong|long|short|medium|tiny}
- Moving store_decimal(), val_decimal(), get_date(), store_time_dec(),
get_date(), val_bool() from Field_num to Field_int
- Adding Field_int::val_str_from_long() and reusing it in
Field_tiny::val_str(), Field_short::val_str(), Field_medium::val_str()
and Field_long::val_str(). This removes a good amount of duplicate code
- Adding "const" qualifier to "virtual bool Field::optimize_range()".
- Adding a new virtual method Field::load_data_set_no_data().
- Overriding Field_timestamp::load_data_set_no_data() and moving
the TIMESTAMP specific code there.
- Overriding Field_geom::load_data_set_no_data() and implementing
GEOMETRY specific behavior, to prevent writing empty strings
when the loaded file ends unexpectedly. This fixes the bug.
- Adding a new test gis-loaddaata.test.
- The test in loaddata.test for CHAR was added simply to record behavior.
The CHAR data type did not change its behaviour (only GEOMRYRY did).
- Additionally, moving duplicate code into a new method
Field::load_data_set_value() and reusing it in three places.
Standard compatible behavior for UPDATE: all assignments in SET
are executed "simultaneously", not left-to-right. And `SET a=b,b=a`
will swap the values.
