use Item->neg to convert generate negative Item_num's
instead of Item_func_neg(Item_num).
Based on the following commit:
Author: Monty <monty@mariadb.org>
Date: Mon May 30 22:44:00 2016 +0300
Make negative number their own token
The negation (-) operator will call Item->neg() one underlying numeric constants
and remove itself (like the NOT() function does today for other NOT functions.
This simplifies things
- -1 is not anymore an expression but a basic_const_item
- improves optimizer
- DEFAULT -1 doesn't need special handling anymore
- When we add DEFAULT expressions, -1 will be treated exactly like 1
- printing of items doesn't anymore put braces around all negative numbers
Other things fixed:
- Fixed that longlong converted to decimal's has a more appropriate size
- Fixed that "-0.0" read into a decimal is interpreted as 0.0
The crash was caused by range optimizer using RANGE_OPT_PARAM::min_key
(and max_key) to store keys. Buffer size was a good upper bound for
range analysis and partition pruning, but not for EITS selectivity
calculations.
Fixed by making these buffers variable-size. The sizes are calculated
from [pseudo]indexes used for range analysis.
Part#1.
table_cond_selectivity() should discount selectivity of table'
conditions only when ity counts that selectivity to begin with.
For non-ref-based access methods (ALL/range/index_merge/etc),
we start with sel=1.0 and hence do not need to discount any
selectivities.
MDEV-5980: EITS: if condition is used for REF access, its selectivity is still in filtered%
MDEV-5985: EITS: selectivity estimates look illogical for join and non-key equalities
MDEV-6003: EITS: ref access, keypart2=const vs keypart2=expr - inconsistent filtered% value
- Made a number of fixes in table_cond_selectivity() so that it returns
correct selectivity estimates.
- Added comments in related code.
Better comments
MDEV-5985: EITS: selectivity estimates look illogical for join and non-key equalities
MDEV-6003: EITS: ref access, keypart2=const vs keypart2=expr - inconsistent filtered% value
- Made a number of fixes in table_cond_selectivity() so that it returns
correct selectivity estimates.
- Added comments in related code.
MDEV-5984: EITS: Incorrect filtered% value for single-table select with range access
- Fix calculate_cond_selectivity_for_table() to work correctly with range accesses
over multi-component keys:
= First, take selectivity of all possible range scans into account. Remember which
fields were used bt the range scans.
= Then, calculate selectivity produced by sargable predicates on fields. If a
field was used in a possible range access, assume its selectivity is already
taken into account.
- Fix table_cond_selectivity(): when quick select is used, selectivity of
COND(table) is taken into account in matching_candidates_in_table(). In
table_cond_selectivity() we should not apply it for the second time.
