Spider connection string is a comma-separated parameter definitions,
where each definition is of the form "<param_title> <param_value>",
where <param_value> is quote delimited on both ends, with backslashes
acting as an escaping prefix.
Despite the simple syntax, the existing spider connection string
parser was poorly-written, complex, hard to reason and error-prone,
causing issues like the one described in MDEV-31117. For example it
treated param title the same way as param value when assigning, and
have nonsensical fields like delim_title_len and delim_title.
Thus as part of the bugfix, we clean up the spider comment connection
string parsing, including:
- Factoring out some code from the parsing function
- Simplify the struct `st_spider_param_string_parse`
- And any necessary changes caused by the above changes
The test innodb.row_size_error_log_warnings_3 that was added in
commit 372b0e6355fbb6b7dc490b64da13e784c09aeec8 (MDEV-20194)
failed to take into account the earlier adjustment in
commit cf574cf53b168992b911d5fc32c590a6ee03a56a (MDEV-27634)
that is specific to many GNU/Linux distributions for the s390x.
Remove bogus references to replaced Google contributions
In commit 03ca6495df31313c96e38834b9a235245e2ae2a8 and
commit ff5d306e296350e7489dd3decb01bad18d135411
we forgot to remove some Google copyright notices related to
a contribution of using atomic memory access in the old InnoDB
mutex_t and rw_lock_t implementation.
The copyright notices had been mostly added in
commit c6232c06faff4bf7381958925e1f9c5521a6b8b9
due to commit a1bb700fd2c29b8cbc7f1eeac03f16e0e5887e25.
The following Google contributions remain:
* some logic related to the parameter innodb_io_capacity
* innodb_encrypt_tables, added in MariaDB Server 10.1
buf_LRU_block_remove_hashed(): Remove a comment that had been added
in mysql/mysql-server@aad1c7d0dd8a152ef6bb685356c68ad9978d686a
and apparently referring to buf_LRU_invalidate_tablespace(),
which was later replaced with buf_LRU_flush_or_remove_pages() and
ultimately with buf_flush_remove_pages() and buf_flush_list_space().
All that code is covered by buf_pool.mutex. The note about releasing
the hash_lock for the buf_pool.page_hash slice would actually apply to
the last reference to hash_lock in buf_LRU_free_page(), for the
case zip=false (retaining a ROW_FORMAT=COMPRESSED page while
discarding the uncompressed one).
MDEV-29693 ANALYZE TABLE still flushes table definition cache when engine-independent statistics is used
This commits enables reloading of engine-independent statistics
without flushing the table from table definition cache.
This is achieved by allowing multiple version of the
TABLE_STATISTICS_CB object and having independent pointers to it in
TABLE and TABLE_SHARE. The TABLE_STATISTICS_CB object have reference
pointers and are freed when no one is pointing to it anymore.
TABLE's TABLE_STATISTICS_CB pointer is updated to use the
TABLE_SHARE's pointer when read_statistics_for_tables() is called at
the beginning of a query.
Main changes:
- read_statistics_for_table() will allocate an new TABLE_STATISTICS_CB
object.
- All get_stat_values() functions has a new parameter that tells
where collected data should be stored. get_stat_values() are not
using the table_field object anymore to store data.
- All get_stat_values() functions returns 1 if they found any
data in the statistics tables.
Other things:
- Fixed INSERT DELAYED to not read statistics tables.
- Removed Statistics_state from TABLE_STATISTICS_CB as this is not
needed anymore as wer are not changing TABLE_SHARE->stats_cb while
calculating or loading statistics.
- Store values used with store_from_statistical_minmax_field() in
TABLE_STATISTICS_CB::mem_root. This allowed me to remove the function
delete_stat_values_for_table_share().
- Field_blob::store_from_statistical_minmax_field() is implemented
but is not normally used as we do not yet support EIS statistics
for blobs. For example Field_blob::update_min() and
Field_blob::update_max() are not implemented.
Note that the function can be called if there is an concurrent
"ALTER TABLE MODIFY field BLOB" running because of a bug in
ALTER TABLE where it deletes entries from column_stats
before it has an exclusive lock on the table.
- Use result of field->val_str(&val) as a pointer to the result
instead of val (safetly fix).
- Allocate memory for collected statistics in THD::mem_root, not in
in TABLE::mem_root. This could cause the TABLE object to grow if a
ANALYZE TABLE was run many times on the same table.
This was done in allocate_statistics_for_table(),
create_min_max_statistical_fields_for_table() and
create_min_max_statistical_fields_for_table_share().
- Store in TABLE_STATISTICS_CB::stats_available which statistics was
found in the statistics tables.
- Removed index_table from class Index_prefix_calc as it was not used.
- Added TABLE_SHARE::LOCK_statistics to ensure we don't load EITS
in parallel. First thread will load it, others will reuse the
loaded data.
- Eliminate read_histograms_for_table(). The loading happens within
read_statistics_for_tables() if histograms are needed.
One downside is that if we have read statistics without histograms
before and someone requires histograms, we have to read all statistics
again (once) from the statistics tables.
A smaller downside is the need to call alloc_root() for each
individual histogram. Before we could allocate all the space for
histograms with a single alloc_root.
- Fixed bug in MyISAM and Aria where they did not properly notice
that table had changed after analyze table. This was not a problem
before this patch as then the MyISAM and Aria tables where flushed
as part of ANALYZE table which did hide this issue.
- Fixed a bug in ANALYZE table where table->records could be seen as 0
in collect_statistics_for_table(). The effect of this unlikely bug
was that a full table scan could be done even if
analyze_sample_percentage was not set to 1.
- Changed multiple mallocs in a row to use multi_alloc_root().
- Added a mutex protection in update_statistics_for_table() to ensure
that several tables are not updating the statistics at the same time.
Some of the changes in sql_statistics.cc are based on a patch from
Oleg Smirnov <email address hidden>
