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23 commits

Author SHA1 Message Date
Sergei Petrunia
0940a96940 MDEV-18478 ANALYZE for statement should show selectivity of ICP, part#2
Part#2, variant 2: Make the printed r_ values in JSON output consistent.
After this patch, ANALYZE output has:

- r_index_rows (NEW) - Observed number of rows before ICP or Rowid Filtering
  checks. This is a per-scan average. like r_rows and "rows" are.

- r_rows (AS BEFORE) - Observed number of rows after ICP and Rowid Filtering.

- r_icp_filtered (NEW) - Observed selectivity of ICP condition.

- (AS BEFORE) observed selectivity of Rowid Filter is in
  $.rowid_filter.r_selectivity_pct

- r_total_filtered - Observed combined selectivity: fraction of rows left
  after applying ICP condition, Rowid Filter, and attached_condition.
  This is now comparable with "filtered" and is printed right after it.

- r_filtered (AS BEFORE) - Observed selectivity of "attached_condition".

Tabular ANALYZE output is not changed. Note that JSON's r_filtered and
r_rows have the same meanings as before and have the same meaning as in
tabular output.
2024-04-23 22:55:22 +03:00
Marko Mäkelä
f2b4972bd4 Merge 10.11 into 11.0 2023-07-26 15:13:06 +03:00
Marko Mäkelä
bce3ee704f Merge 10.10 into 10.11 2023-07-26 14:44:43 +03:00
Marko Mäkelä
864bbd4d09 Merge 10.6 into 10.9 2023-07-26 13:42:23 +03:00
Sergei Petrunia
6e484c3bd9 MDEV-31577: Make ANALYZE FORMAT=JSON print innodb stats
ANALYZE FORMAT=JSON output now includes table.r_engine_stats which
has the engine statistics. Only non-zero members are printed.

Internally: EXPLAIN data structures Explain_table_acccess and
Explain_update now have handler* handler_for_stats pointer.
It is used to read statistics from handler_for_stats->handler_stats.

The following applies only to 10.9+, backport doesn't use it:

Explain data structures exist after the tables are closed. We avoid
walking invalid pointers using this:
- SQL layer calls Explain_query::notify_tables_are_closed() before
  closing tables.
- After that call, printing of JSON output is disabled. Non-JSON output
  can be printed but we don't access handler_for_stats when doing that.
2023-07-21 16:50:11 +03:00
Sergei Petrunia
c7fe8e51de Merge 10.11 into 11.0 2023-04-17 16:50:01 +03:00
Marko Mäkelä
656c2e18b1 Merge 10.10 into 10.11 2023-04-14 13:08:28 +03:00
Marko Mäkelä
1d1e0ab2cc Merge 10.6 into 10.8 2023-04-12 15:50:08 +03:00
Sergei Petrunia
31536b2477 MDEV-30972: ANALYZE FORMAT=JSON: some time is unaccounted-for in BNL-H join
After MDEV-30830 has added block-nl-join.r_unpack_time_ms, it became
apparent that there is some unaccounted-for time in BNL join operation,
namely the time that is spent after unpacking the join buffer record.

Fix this by adding a Gap_time_tracker to track the time that is spent
after unpacking the join buffer record and before any next time tracking.
The collected time is printed in block-nl-join.r_other_time_ms.

Reviewed by: Monty <monty@mariadb.org>
2023-04-04 12:18:37 +03:00
Sergei Petrunia
0269d82d53 ANALYZE FORMAT=JSON: Backport block-nl-join.r_unpack_time_ms from 11.0 +fix MDEV-30830.
Also fix it to work with hashed join (MDEV-30830).

Reviewed by: Monty <monty@mariadb.org>
2023-04-04 12:18:29 +03:00
Sergei Petrunia
dc1d6213f9 MDEV-30806: ANALYZE FORMAT=JSON: better support for BNL and BNL-H joins
In block-nl-join, add:

- r_loops - this shows how many incoming record combinations this
  query plan node had.

- r_effective_rows - this shows the average number of matching rows
  that this table had for each incoming record combination. This is
  comparable with r_rows in non-blocked access methods.
  For BNL-joins, it is always equal to
   $.table.r_rows * $.table.r_filtered
  For BNL-H joins the value cannot be computed from other values

Reviewed by: Monty <monty@mariadb.org>
2023-03-31 14:11:32 +03:00
Sergei Petrunia
6c4076fac4 MDEV-30032: EXPLAIN FORMAT=JSON output: part : print 'loops'. 2023-02-03 11:22:17 +03:00
Sergei Petrunia
ffe0beca25 MDEV-30032: EXPLAIN FORMAT=JSON output: print costs
Basic printout for join and table execution costs.
2023-02-03 11:01:24 +03:00
Monty
b66cdbd1ea Changing all cost calculation to be given in milliseconds
This makes it easier to compare different costs and also allows
the optimizer to optimizer different storage engines more reliably.

- Added tests/check_costs.pl, a tool to verify optimizer cost calculations.
  - Most engine costs has been found with this program. All steps to
    calculate the new costs are documented in Docs/optimizer_costs.txt

- User optimizer_cost variables are given in microseconds (as individual
  costs can be very small). Internally they are stored in ms.
- Changed DISK_READ_COST (was DISK_SEEK_BASE_COST) from a hard disk cost
  (9 ms) to common SSD cost (400MB/sec).
- Removed cost calculations for hard disks (rotation etc).
- Changed the following handler functions to return IO_AND_CPU_COST.
  This makes it easy to apply different cost modifiers in ha_..time()
  functions for io and cpu costs.
  - scan_time()
  - rnd_pos_time() & rnd_pos_call_time()
  - keyread_time()
- Enhanched keyread_time() to calculate the full cost of reading of a set
  of keys with a given number of ranges and optional number of blocks that
  need to be accessed.
- Removed read_time() as keyread_time() + rnd_pos_time() can do the same
  thing and more.
- Tuned cost for: heap, myisam, Aria, InnoDB, archive and MyRocks.
  Used heap table costs for json_table. The rest are using default engine
  costs.
- Added the following new optimizer variables:
  - optimizer_disk_read_ratio
  - optimizer_disk_read_cost
  - optimizer_key_lookup_cost
  - optimizer_row_lookup_cost
  - optimizer_row_next_find_cost
  - optimizer_scan_cost
- Moved all engine specific cost to OPTIMIZER_COSTS structure.
- Changed costs to use 'records_out' instead of 'records_read' when
  recalculating costs.
- Split optimizer_costs.h to optimizer_costs.h and optimizer_defaults.h.
  This allows one to change costs without having to compile a lot of
  files.
- Updated costs for filter lookup.
- Use a better cost estimate in best_extension_by_limited_search()
  for the sorting cost.
- Fixed previous issues with 'filtered' explain column as we are now
  using 'records_out' (min rows seen for table) to calculate filtering.
  This greatly simplifies the filtering code in
  JOIN_TAB::save_explain_data().

This change caused a lot of queries to be optimized differently than
before, which exposed different issues in the optimizer that needs to
be fixed.  These fixes are in the following commits.  To not have to
change the same test case over and over again, the changes in the test
cases are done in a single commit after all the critical change sets
are done.

InnoDB changes:
- Updated InnoDB to not divide big range cost with 2.
- Added cost for InnoDB (innobase_update_optimizer_costs()).
- Don't mark clustered primary key with HA_KEYREAD_ONLY. This will
  prevent that the optimizer is trying to use index-only scans on
  the clustered key.
- Disabled ha_innobase::scan_time() and ha_innobase::read_time() and
  ha_innobase::rnd_pos_time() as the default engine cost functions now
  works good for InnoDB.

Other things:
- Added  --show-query-costs (\Q) option to mysql.cc to show the query
  cost after each query (good when working with query costs).
- Extended my_getopt with GET_ADJUSTED_VALUE which allows one to adjust
  the value that user is given. This is used to change cost from
  microseconds (user input) to milliseconds (what the server is
  internally using).
- Added include/my_tracker.h  ; Useful include file to quickly test
  costs of a function.
- Use handler::set_table() in all places instead of 'table= arg'.
- Added SHOW_OPTIMIZER_COSTS to sys variables. These are input and
  shown in microseconds for the user but stored as milliseconds.
  This is to make the numbers easier to read for the user (less
  pre-zeros).  Implemented in 'Sys_var_optimizer_cost' class.
- In test_quick_select() do not use index scans if 'no_keyread' is set
  for the table. This is what we do in other places of the server.
- Added THD parameter to Unique::get_use_cost() and
  check_index_intersect_extension() and similar functions to be able
  to provide costs to called functions.
- Changed 'records' to 'rows' in optimizer_trace.
- Write more information to optimizer_trace.
- Added INDEX_BLOCK_FILL_FACTOR_MUL (4) and INDEX_BLOCK_FILL_FACTOR_DIV (3)
  to calculate usage space of keys in b-trees. (Before we used numeric
  constants).
- Removed code that assumed that b-trees has similar costs as binary
  trees. Replaced with engine calls that returns the cost.
- Added Bitmap::find_first_bit()
- Added timings to join_cache for ANALYZE table (patch by Sergei Petrunia).
- Added records_init and records_after_filter to POSITION to remember
  more of what best_access_patch() calculates.
- table_after_join_selectivity() changed to recalculate 'records_out'
  based on the new fields from best_access_patch()

Bug fixes:
- Some queries did not update last_query_cost (was 0). Fixed by moving
  setting thd->...last_query_cost in JOIN::optimize().
- Write '0' as number of rows for const tables with a matching row.

Some internals:
- Engine cost are stored in OPTIMIZER_COSTS structure.  When a
  handlerton is created, we also created a new cost variable for the
  handlerton. We also create a new variable if the user changes a
  optimizer cost for a not yet loaded handlerton either with command
  line arguments or with SET
  @@global.engine.optimizer_cost_variable=xx.
- There are 3 global OPTIMIZER_COSTS variables:
  default_optimizer_costs   The default costs + changes from the
                            command line without an engine specifier.
  heap_optimizer_costs      Heap table costs, used for temporary tables
  tmp_table_optimizer_costs The cost for the default on disk internal
                            temporary table (MyISAM or Aria)
- The engine cost for a table is stored in table_share. To speed up
  accesses the handler has a pointer to this. The cost is copied
  to the table on first access. If one wants to change the cost one
  must first update the global engine cost and then do a FLUSH TABLES.
  This was done to be able to access the costs for an open table
  without any locks.
- When a handlerton is created, the cost are updated the following way:
  See sql/keycaches.cc for details:
  - Use 'default_optimizer_costs' as a base
  - Call hton->update_optimizer_costs() to override with the engines
    default costs.
  - Override the costs that the user has specified for the engine.
  - One handler open, copy the engine cost from handlerton to TABLE_SHARE.
  - Call handler::update_optimizer_costs() to allow the engine to update
    cost for this particular table.
  - There are two costs stored in THD. These are copied to the handler
    when the table is used in a query:
    - optimizer_where_cost
    - optimizer_scan_setup_cost
- Simply code in best_access_path() by storing all cost result in a
  structure. (Idea/Suggestion by Igor)
2023-02-02 23:54:45 +03:00
Luis Eduardo Oliveira Lizardo
ad7631bdce MDEV-28926 Add time spent on query optimizer to JSON ANALYZE ()
* Add query optimizer timer to ANALYZE FORMAT=JSON

* Adapt tests and results

* Change logic to always close the writer after printing query blocks
2022-10-26 09:18:29 +03:00
Sergei Krivonos
73df7a3009 MDEV-27036: resolve duplicated key issues of JSON tracing outputs:
MDEV-27036: repeated "table" key resolve for print_explain_json

MDEV-27036: duplicated keys in best_access_path

MDEV-27036: Explain_aggr_filesort::print_json_members: resolve duplicated "filesort" member in Json object

MDEV-27036: Explain_basic_join::
            print_explain_json_interns fixed start_dups_weedout case for main.explain_json test
2021-11-26 15:11:06 +02:00
Monty
27d9986c1b Added more digits to JSON output of double
sprintf() format of double changed from '%lg' to '%-.11lg'

The change was to make it easier to read optimizer trace output
with tables that has millions of records.
2020-04-19 17:33:52 +03:00
Varun Gupta
0c35e80dc9 MDEV-21838: Add information about packed addon fields in ANALYZE FORMAT=JSON
It is useful to know whether sorting uses addon fields[packed|unpacked] or ROWID.
Provide this information in ANALYZE FORMAT=JSON output.
2020-02-28 15:15:51 +05:30
Sergei Petrunia
68ed3a81f2 MDEV-20854: ANALYZE for statements: not clear where the time is spent
Count the "gap" time between table accesses and display it as
r_other_time_ms in the "table" element.

* The advantage of this approach is that it doesn't add any new
  my_timer_cycles() calls.
* The disadvantage is that the definition of what is done during
  "other time" is not that clear: it includes checking the WHERE
  (for this table), constructing index lookup tuple (for the next table)
  writing to GROUP BY temporary table (as we dont account for that time
  separately [yet], etc)
2019-11-12 14:40:00 +03:00
Varun Gupta
d6db6df995 MDEV-17903: New optimizer defaults: change optimize_join_buffer_size to be ON
optimize_join_buffer_size is switched ON.
2019-02-19 14:27:24 +05:30
Igor Babaev
658128af43 MDEV-16188 Use in-memory PK filters built from range index scans
This patch contains a full implementation of the optimization
that allows to use in-memory rowid / primary filters built for range  
conditions over indexes. In many cases usage of such filters reduce  
the number of disk seeks spent for fetching table rows.

In this implementation the choice of what possible filter to be applied  
(if any) is made purely on cost-based considerations.

This implementation re-achitectured the partial implementation of
the feature pushed by Galina Shalygina in the commit
8d5a11122c.

Besides this patch contains a better implementation of the generic  
handler function handler::multi_range_read_info_const() that
takes into account gaps between ranges when calculating the cost of
range index scans. It also contains some corrections of the
implementation of the handler function records_in_range() for MyISAM.

This patch supports the feature for InnoDB and MyISAM.
2019-02-03 14:56:12 -08:00
Sergei Golubchik
36e59752e7 Merge branch '10.2' into 10.3 2018-06-30 16:39:20 +02:00
Michael Widenius
a7abddeffa Create 'main' test directory and move 't' and 'r' there 2018-03-29 13:59:44 +03:00
Renamed from mysql-test/r/analyze_stmt_orderby.result (Browse further)