Same as MDEV-29579. For some reason, libodbc does not clean up
properly if unloaded too early with the dlclose() of spider. So we add
UNIQUE symbols to spider so the spider does not reload in dlclose().
This change, however, uncovers some hidden problems in the spider
codebase, for which we move the initialisation of some spider global
variables into the initialisation of spider itself.
Spider has some global variables. Their initialisation should be done
in the initialisation of spider itself, otherwise, if spider were
re-initialised without these symbol being unloaded, the values could
be inconsistent and causing issues.
One such issue is caused by the variables
spider_mon_table_cache_version and spider_mon_table_cache_version_req.
They are used for resetting the spider monitoring table cache and have
initial values of 0 and 1 respectively. We have that always
spider_mon_table_cache_version_req >= spider_mon_table_cache_version,
and when the relation is strict, the cache is reset,
spider_mon_table_cache_version is brought to be equal to
spider_mon_table_cache_version_req, and the cache is searched for
matching table_name, db_name and link_idx. If the relation is equal,
no reset would happen and the cache would be searched directly.
When spider is re-inited without resetting the values of
spider_mon_table_cache_version and spider_mon_table_cache_version_req
that were set to be equal in the previous cache reset action, the
cache was emptied in the previous spider deinit, which would result in
HA_ERR_KEY_NOT_FOUND unexpectedly.
An alternative way to fix this issue would be to call the spider udf
spider_flush_mon_cache_table(), which increments
spider_mon_table_cache_version_req thus making sure the inequality is
strict. However, there's no reason for spider to initialise these
global variables on dlopen(), rather than on spider init, which is
cleaner and "purer".
To reproduce this issue, simply revert the changes involving the two
variables and then run:
mtr --no-reorder spider.ha{,_part}
Some fixes related to commit f838b2d799 and
Rows_log_event::do_apply_event() and Update_rows_log_event::do_exec_row()
for system-versioned tables were provided by Nikita Malyavin.
This was required by test versioning.rpl,trx_id,row.
There are two array fields in spider_share with similar names:
share->use_sql_dbton_ids that maps from i to the i-th dbton used by
share. Thus it should be used only when i iterates over all distinct
dbtons used by share.
share->sql_dbton_ids that maps from i to the dbton used by the i-th
link of the share. Thus it should be used only when i iterates over
all links of a share.
We correct instances where share->sql_dbton_ids should be used instead
of share->use_sql_dbton_ids.
This will avoid issues like MDEV-32486
IDs used in
- spider_alloc_calc_mem_init()
- spider_string::init_calc_mem()
- spider_malloc()
- spider_bulk_alloc_mem()
- spider_bulk_malloc()
Spider gbh query rewrite should get table for fields in a simple way.
Add a method spider_fields::find_table that searches its table holders
to find table for a given field. This way we will be able to get rid
of the first pass during the gbh creation where field_chains and
field_holders are created.
We also check that the field belongs to a spider table while walking
through the query, so we could remove
all_query_fields_are_query_table_members(). However, this requires an
earlier creation of the table_holder so that tables are added before
checking. We do that, and in doing so, also decouple table_holder and
spider_fields
Remove unused methods and fields. Add comments.
The MDEV-29693 conflict resolution is from Monty, as well as is
a bug fix where ANALYZE TABLE wrongly built histograms for
single-column PRIMARY KEY.
Also includes a fix for safe_malloc error reporting.
Other things:
- Copied main.log_slow from 10.4 to avoid mtr issue
Disabled test:
- spider/bugfix.mdev_27239 because we started to get
+Error 1429 Unable to connect to foreign data source: localhost
-Error 1158 Got an error reading communication packets
- main.delayed
- Bug#54332 Deadlock with two connections doing LOCK TABLE+INSERT DELAYED
This part is disabled for now as it fails randomly with different
warnings/errors (no corruption).
Removed some redundant hint related string literals from
spd_db_conn.cc
Clean up SPIDER_PARAM_*_[CHAR]LEN[S]
Adding tests covering monitoring_kind=2. What it does is that it reads
from mysql.spider_link_mon_servers with matching db_name, table_name,
link_id, and does not do anything about that...
How monitoring_* can be useful: in the deprecated spider high
availability feature, when one remote fails, spider will try another
remote, which apparently makes use of these table parameters.
A test covering the query_cache_sync table param. Some further tests
on some spider table params.
Wrapper should be case insensitive.
Code documentation on spider priority binary tree.
Add an assertion that static_key_cardinality is always -1. All tests
pass still
The direct aggregate mechanism sems to be only intended to work when
otherwise a full table scan query will be executed from the spider
node and the aggregation done at the spider node too. Typically this
happens in sub_select(). In the test spider.direct_aggregate_part
direct aggregate allows to send COUNT statements directly to the data
nodes and adds up the results at the spider node, instead of iterating
over the rows one by one at the spider node.
By contrast, the group by handler (GBH) typically sends aggregated
queries directly to data nodes, in which case DA does not improve the
situation here.
That is why we should fix it by disabling DA when GBH is used.
There are other reasons supporting this change. First, the creation of
GBH results in a call to change_to_use_tmp_fields() (as opposed to
setup_copy_fields()) which causes the spider DA function
spider_db_fetch_for_item_sum_funcs() to work on wrong items. Second,
the spider DA function only calls direct_add() on the items, and the
follow-up add() needs to be called by the sql layer code. In
do_select(), after executing the query with the GBH, it seems that the
required add() would not necessarily be called.
Disabling DA when GBH is used does fix the bug. There are a few
other things included in this commit to improve the situation with
spider DA:
1. Add a session variable that allows user to disable DA completely,
this will help as a temporary measure if/when further bugs with DA
emerge.
2. Move the increment of direct_aggregate_count to the spider DA
function. Currently this is done in rather bizarre and random
locations.
3. Fix the spider_db_mbase_row creation so that the last of its row
field (sentinel) is NULL. The code is already doing a null check, but
somehow the sentinel field is on an invalid address, causing the
segfaults. With a correct implementation of the row creation, we can
avoid such segfaults.
The existing (incorrect) overriding mechanism is:
Non-minus-one var value overrides table param overrides default value.
Before MDEV-27169, unspecified var value is -1. So if the user sets
both the var to be a value other than -1 and the table param, the var
value will prevail, which is incorrect.
After MDEV-27169, unspecified var value is default value. So if the
user does not set the var but sets the table param, the default value
will prevail, which is even more incorrect.
This patch fixes it so that table param, if specified, always
overrides var value, and the latter if not specified or set to -1,
falls back to the default value
We achieve this by replacing all such overriding in spd_param.cc with
macros that override in the correct way, and removing all the
"overriding -1" lines involving table params in
spider_set_connect_info_default() except for those table params not
defined as sysvar/thdvar in spd_params.cc
We also introduced macros for non-overriding sysvar and thdvar, so
that the code is cleaner and less error-prone
In server versions where MDEV-27169 has not been applied, we also
backport the patch, that is, replacing -1 default values with real
default values
In server versions where MDEV-28006 has not been applied, we do the
same for udf params
The conn_kind, which stands for "connection kind", is no longer useful
because the HandlerSocket support is deleted and Spider now has only
one connection kind, SPIDER_CONN_KIND_MYSQL. Remove conn_kind and
related code.
Signed-off-by: Yuchen Pei <yuchen.pei@mariadb.com>
Reviewed-by: Nayuta Yanagisawa <nayuta.yanagisawa@mariadb.com>
