This task deals with packing the sort key inside the sort buffer, which would
lead to efficient usage of the memory allocated for the sort buffer.
The changes brought by this feature are
1) Sort buffers would have sort keys of variable length
2) The format for sort keys inside the sort buffer would look like
|<sort_length><null_byte><key_part1><null_byte><key_part2>.......|
sort_length is the extra bytes that are required to store the variable
length of a sort key.
3) When packing of sort key is done we store the ORIGINAL VALUES inside
the sort buffer and not the STRXFRM form (mem-comparable sort keys).
4) Special comparison function packed_keys_comparison() is introduced
to compare 2 sort keys.
This patch also contains contributions from Sergei Petrunia.
MDEV-21854 xa commit `xid` one phase for already prepared transaction must always error out
Added state and one-phase option checks to XA "external" commit/rollback
branches. While the XA standard does not prohibit it,
Commit and Rollback of an XA external to the current ongoing transaction
is not allowed; after all the current transaction may rollback
to not being able to revert that decision.
The default keyread_time() was optimized for blocks and not suitable for
HEAP. The effect was the HEAP prefered table scans over ranges for btree
indexes.
Fixed also get_sweep_read_cost() for HEAP tables.
- Move testing of my_writer to inline functions to avoid calls
- Made more functions inline. Especially thd->thread_started()
is now very optimized!
- Moved Opt_trace_stmt classe to opt_trace_context.h to get critical
functions inline
- Added unlikely() to optimize for not having optimizer trace enabled
- Made THD::trace_started() inline
- Added 'if (trace_enabled())' around some potentially expensive code
(not many found)
- Added ASSERT's to ensure we don't call expensive optimizer trace calls
if optimizer trace is not enabled
- Added length to Json_writer functions to speed up buffer writes
when optimizer trace is enabled.
- Changed LEX_CSTRING argument handling to not send full struct to writer
function on_add_str() functions now trusts length arguments
- Don't try to push down SELECTs that have a side effect
- In case the storage engine did support pushdown of SELECT with an INTO
clause, write the rows we've got from it into select->join->result,
and not thd->protocol. This way, SELECT ... INTO ... FROM
smart_engine_table will put the result into where instructed, and
NOT send it to the client.
This patch adds support of RENAME INDEX operation to the ALTER TABLE
statement. Code which determines if ALTER TABLE can be done in-place
for "simple" storage engines like MyISAM, Heap and etc. was updated to
handle ALTER TABLE ... RENAME INDEX as an in-place operation. Support
for in-place ALTER TABLE ... RENAME INDEX for InnoDB was covered by
MDEV-13301.
Syntax changes
==============
A new type of <alter_specification> is added:
<rename index clause> ::= RENAME ( INDEX | KEY ) <oldname> TO <newname>
Where <oldname> and <newname> are identifiers for old name and new
name of the index.
Semantic changes
================
The result of "ALTER TABLE t1 RENAME INDEX a TO b" is a table which
contents and structure are identical to the old version of 't1' with
the only exception index 'a' being called 'b'.
Neither <oldname> nor <newname> can be "primary". The index being
renamed should exist and its new name should not be occupied
by another index on the same table.
Related to: WL#6555, MDEV-13301
The existing syntax for renaming a column uses "ALTER TABLE ... CHANGE"
command. This requires full column specification to rename the column.
This patch adds new syntax "ALTER TABLE ... RENAME COLUMN", which do not
expect users to provide full column specification. It means that the new
syntax would pick in-place or copy algorithm in the same way as that of
existing "ALTER TABLE ... CHANGE" command. The existing syntax
"ALTER TABLE ... CHANGE" will continue to work.
Syntax changes
==============
ALTER TABLE tbl_name
[alter_specification [, alter_specification] ...]
[partition_options]
Following is a new <alter_specification> added:
| RENAME COLUMN <oldname> TO <newname>
Where <oldname> and <newname> are identifiers for old name and new
name of the column.
Related to: WL#10761
When connections go to same node and deadlock happens, BF abort should
not happen for victim thread. Fixed by guarding
`wsrep_handle_SR_rollback()` so that is called only for SR transactions.
Co-authored-by: Seppo Jaakola <seppo.jaakola@iki.fi>
Co-authored-by: Daniele Sciascia <daniele.sciascia@galeracluster.com>
XA specification doesn't permit empty gtrid. It is now enforced by this
patch. This solution was agreed in favour of fixing InnoDB, which doesn't
expect empty XID since early 10.5.
Also fixed wrong assertion (and added a test cases) that didn't permit
64 bytes gtrid + 64 bytes bqual.
ha_partition: Remove redundant 'virtual' keywords and add
missing 'override'.
FIXME: handler::table_type() is not declared virtual, yet ha_partition
and ha_sequence are seemingly trying to override it.
