ha_heap::external_lock contains some consistency checks for the table,#
in a debug compilation.
This code suffers from lack of synchronization, in a rare case
where mysql_lock_tables() fail, and unlock is forced, even if lock was
not previously taken.
To workaround, require EXTRA_DEBUG compile definition in order to activate
the consistency checks.The code still might be useful in some cases - but
the audience are developers looking for errors in single-threaded scenarios,
rather than multiuser stress-tests.
I_S tables were materialized too late, an attempt to use table
statistics before the table was created caused a crash.
Let's move table creation up. it only needs read_set to
be calculated properly, this happens in JOIN::optimize_inner(),
after semijoin transformation.
Note that tables are not populated at that point, so most of the
statistics would make no sense anyway. But at least field sizes
will be correct. And it won't crash.
Reimplement MDEV-14275 Improving memory utilization for information schema
Postpone temp table instantiation until after setup_fields().
Replace all unused (not marked in read_set) columns in an I_S table
with CHAR(0). This can drastically reduce the footprint of a MEMORY
table (a TABLE_CATALOG alone is 1538 bytes per row).
This does not change the engine. If the table was decided to be Aria
(because of, say, blobs) then after optimization it'll stay Aria
even if all blobs were removed.
Note 1: when transforming table structure, share->blob_fields is
preserved, otherwise Aria might switch from DYNAMIC to STATIC row format
and expect a special field for a deleted mark, which create_tmp_tabe
didn't provide.
Note 2: optimizer was doing handler::info() (to know the number of rows)
before the temp table is populated. That didn't make much sense. Now
it's done before the table is even instantiated. Preserve the old
behavior and report 0 rows.
This reverts e2664ee836 and a8458a2345
Don't save/restore HP_INFO as it could be changed by a concurrent thread.
different parts of HP_INFO are protected by different mutexes and
the mutex that protect most of the HP_INFO does not protect its open_list
data.
As a bonus, make heap_check_heap() to take const HP_INFO* and not
make any changes there whatsoever.
In debug build, whenever MEMORY table instance gets closed it performs
consistency check without protection. It may cause server crash if
executed concurrently with DML.
Moved consistency check to ha_heap::external_lock(F_UNLCK), so that it
is protected by THR_LOCK.
heap_scan() makes info->next_block to be either an integer number
of share->block.records_in_block's or the total number of
records in the table. So when this total number or records changes,
info->next_block needs to be recalculated to take it into account.
This is a different fix for "Fixes a problem with heap when scanning and insert rows at the same time"
cmake -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_BUILD_TYPE=Debug
Maintainer mode makes all warnings errors. This patch fix warnings. Mostly about
deprecated `register` keyword.
Too much warnings came from Mroonga and I gave up on it.
This was added in 29fa72526a (in 2000) and nothing defines
NEW_HASH_FUNCTION. A low collision is the wrong tradeoff,
it should be focused on throughput.
d405bee058 shows the existing function
is pretty cpu intensive and needs to be improved as well.
main.derived_cond_pushdown: Move all 10.3 tests to the end,
trim trailing white space, and add an "End of 10.3 tests" marker.
Add --sorted_result to tests where the ordering is not deterministic.
main.win_percentile: Add --sorted_result to tests where the
ordering is no longer deterministic.
INFO (HP_INFO)
Description:- Server crashes due to memory overflow.
Analysis:- Bytes for storing key length is wrongly set
for HEAP tables.
Fix:- Bytes used to store the key length is properly set
inside "heap_create()".
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.
Handle string length as size_t, consistently (almost always:))
Change function prototypes to accept size_t, where in the past
ulong or uint were used. change local/member variables to size_t
when appropriate.
This fix excludes rocksdb, spider,spider, sphinx and connect for now.
