(to simplify further MDEV-8909 changes)
1. Better semantic readability:
- Moving get_select_lex_derived inside select_derived_init
and decomposing it into get_select_lex and
$1->init_nested_join(lex->thd)
- Moving DBUG_ASSERT($1 == Lex->current_select) inside
select_derived_init
Now init_nested_join() and end_nested_join() reside inside
the same rule select_derived_init.
(It's very likely that they can be further removed,
as there are no any joins in this rule).
3. Better grammar readability:
Moving SELECT_SYM from select_derived_init to derived_query_specification.
It's easier to read a rule when it starts from a terminal symbol.
1. Moving the "| get_select_lex_derived select_derived_init" part of
select_derived into a separate new rule derived_query_specification.
2. Using derived_query_specification directly in select_derived_union
rather than in select_derived.
3. Moving the sequence "opt_order_clause opt_limit_clause opt_select_lock_type"
from select_derived2 to select_derived_union,
after derived_query_specification.
Effectively, the parser now does not go through the sequence
"opt_order_clause opt_limit_clause ... opt_union_order_or_limit" any more.
This fixes the problem with double LIMIT clause and removes 2 shift/reduce
conflicts.
"MDEV-8909 union parser cleanup" changes.
When the server parses a query like
SELECT * FROM (SELECT 1);
a sequence of calls
st_select_lex::init_nested_join() ..
st_select_lex::end_nested_join()
was performed two times (tested in gdb).
Both pairs of calls seem to be redundant for a query
like this, because there are actually no any joins here.
This patch moved "table_ref_select" inside "select_derived",
which revealed that one the pairs was definitely redundant:
After this transformation we got an init_nested_join()
immediately followed by end_nested_join() for the same st_select_lex,
which has no any sense. So this pair of calls was removed.
- Moving "SELECT_SYM select_init2_derived opt_table_expression"
from query_term into a new separate rule query_specification,
and using query_specification in the beginning of query_term.
- query_term now does not have a %type, query_specification has a %type
instead. This removes duplicate code that returns
Lex->current_select->master_unit()->first_select();
- Moving select_options_and_item_list from select_init2
to select_init and view_select_aux
- Renaming select_init2 to select_init3
This will simplify upcoming sql_yacc.yy fixes (e.g. MDEV-10035, MDEV-8909).
An addition to original patch:
- use FN_REFLEN instead of HOST_NAME_MAX (the latter can be undefined)
- avoid calling gethostname() on every prompt construction by caching it
Introduce `\H` option which behaves mostly like `\h`. The only exception is
when the client connects to the server hosted on localhost. In this case, the
hostname will be used instead.
closer the grammar in the SQL Standard:
- <query specification> is only a SELECT followed by
<set quantifier>, <select list> and <table expression>.
- While <query term> includes SELECT queries and derived tables.
This change refactors the "table_expression" rule in sql_yacc.yy.
Queries with subselects and derived tables, as well as "CREATE TABLE ... SELECT"
now return syntax error instead of "Incorrect usage of PROCEDURE and ...".
* simplify the code at default: label
* bugfix: flush the checksum for NULL fields
(perfschema.checksum was failing)
* cleanup: put repeated code into a function
Checksum implementations contain optimizations for calculating
checksums of larger blocks of memory.
This optimization calls my_checksum on a larger block of memory
rather than calling on multiple adjacent memory as its going though
the table columns for each table row.
- Change some static variables to dynamic to ensure that we don't do any memory
allocations before server starts or stops
- Print more memory information on SIGHUP. Fixed output.
- Write out if memory was lost if run with --debug-at-exit
- Fixed wrong #ifdef in sql_cache.cc
- Avoid some realloc() during startup
- Ensure that file_key_management_plugin frees it's memory early, even if
it's linked statically.
- Fixed compiler warnings from unused variables and missing destructors
- Fixed wrong indentation
change buffer not empty
Fix: Allow not empty change buffer when innodb_force_recovery >= 5
and output only a warning to error log.
Note: Before using force recovery you should always take backup
of your database.
When the specification of a WITH table referred to a view
that used a based table with the same name as the WITH table
the server went into an infinite loop because it erroneously
resolved the reference to the base table as the reference to
the WITH table.
With tables used in a view cannot be searched for beyond the
scope the view.
