Details
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Task
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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None
Description
This patch https://github.com/mariadb/server/commit/8eeb689e9fc57afe19a8dbff354b5f9f167867a9
has added MRR support to partitioning engine. If the partitions ' table engine supports MRR, the ha_partition engine will also support it.
The patch was targeting only the Spider engine, but actually it enabled MRR for partitioned DS-MRR engines (InnoDB,MyISAM and Aria). MRR support in MyRocks is not in MariaDB yet, but it in the upstream MyRocks so we will get in the next merge.
MDEV-20611 fixes the basic issues with partitioned DS-MRR. It would be nice to have more test coverage.
The test should have:
- A partitioned table that supports [DS-]MRR. Nice to try different partitioning schemes.
- The table must have an index.
- The query must use MRR or BKA+MRR to read the data from the partitioned table.
- AFAIU, there are two different cases:
- The lookup tuples do not cover all partitioning fields. In this case, for each lookup tuple, ha_partition needs to search for it in all partitions (well, in all partitions that were left after partition pruning)
- The lookup tuples cover partitioned fields. In this case, ha_partition will split the list of ranges into sub-lists that cover individual partitions.
Things to cover:
- non-trivial pushed Index Condition
- Not-exists optimization (Use LEFT JOIN with WHERE inner_table.not_null_col IS NULL
- BKAH (hashed BKA).
Attachments
Issue Links
- relates to
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MDEV-20611 MRR scan over partitioned InnoDB table produces "Out of memory" error
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- Closed
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Activity
Comparison test between the patched build and pre-patch build (352e7667) only hit MDEV-21085 (unrelated).
sql/ha_partition.cc:
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5485 : + if ((tmp= (*file)->ha_rnd_end()))
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5486 : + error= tmp;
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We don't have storage engines that can return an error from rnd_end.
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1592 : 3260248 : + if (get_disk_sweep_mrr_cost(keyno, rows, *flags, bufsz, add_len,
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1593 : : + &dsmrr_cost))
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1594 : 0 : return TRUE;
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This can fire under this condition:
if (elem_size + extra_mem_overhead > *buffer_size) |
return TRUE; /* Buffer has not enough space for even 1 rowid */ |
so this needs a table with a long clustered PK.
Round 10 (there were several rounds in between with nothing worth mentioning).
More unrelated positives due to MDEV-21183, possibly a duplicate of something filed earlier, hard to tell.
Restarting tests again, now without compressed columns.
This will be tested further as part of general optimizer & server testing. Closing.
First test run done, no new failures, moderately affected by
MDEV-14667, MDEV-21085 and some legacy wrong result failures which are reproducible beforeMDEV-20611.Line coverage for the patch from the first run (branch coverage collection hangs, possibly related to MDEV-20694, or something else)
===== File: sql/ha_partition.cc =====5478 : 25198794 : if ((tmp= (*file)->ha_index_end()))5479 : 0 : error= tmp;5480 : : }5481 : 2088492 : + else if ((*file)->inited == RND)5482 : : + {5483 : : + // Possible due to MRR5484 : : + int tmp;5485 : 0 : + if ((tmp= (*file)->ha_rnd_end()))5486 : 0 : + error= tmp;5487 : : + }5488 : 27287374 : } while (*(++file));5489 : 4221504 : destroy_record_priority_queue();5490 : 8443001 : DBUG_RETURN(error);6526 : 2732361 : else if (unlikely((error= handle_unordered_next(table->record[0], FALSE))))6527 : 35527 : DBUG_RETURN(error);6528 : :6529 : 2732359 : + if (!(m_mrr_mode & HA_MRR_NO_ASSOCIATION))6530 : : + {6531 : 2401029 : + *range_info=6532 : 2401029 : + ((PARTITION_KEY_MULTI_RANGE *) m_range_info[m_last_part])->ptr;6533 : : + }6534 : : }6535 : 186298496 : DBUG_RETURN(0);6536 : : }===== File: sql/multi_range_read.cc =====1589 : : }1590 : :1591 : 3260248 : uint add_len= share->key_info[keyno].key_length + primary_file->ref_length;1592 : 3260248 : + if (get_disk_sweep_mrr_cost(keyno, rows, *flags, bufsz, add_len,1593 : : + &dsmrr_cost))1594 : 0 : return TRUE;1595 : : +1596 : : bool force_dsmrr;1597 : : /*1598 : : If mrr_cost_based flag is not set, then set cost of DS-MRR to be minimum of1681 : : @param rows E(Number of rows to be scanned)1682 : : @param flags Scan parameters (HA_MRR_* flags)1683 : : @param buffer_size INOUT Buffer size1684 : : + IN: Buffer of size 0 means the function1685 : : + will determine the best size and return it.1686 : : + @param extra_mem_overhead Extra memory overhead of the MRR implementation1687 : : + (the function assumes this many bytes of buffer1688 : : + space will not be usable by DS-MRR)1689 : : @param cost OUT The cost1690 : :1691 : : @retval FALSE OK1694 : : */1695 : :1696 : 3260262 : bool DsMrr_impl::get_disk_sweep_mrr_cost(uint keynr, ha_rows rows, uint flags,1697 : : + uint *buffer_size,1698 : : + uint extra_mem_overhead,1699 : : + Cost_estimate *cost)1700 : : {1701 : : ulong max_buff_entries, elem_size;1702 : : ha_rows rows_in_full_step;1706 : :1707 : 6520524 : elem_size= primary_file->ref_length +1708 : 3260262 : sizeof(void*) * (!MY_TEST(flags & HA_MRR_NO_ASSOCIATION));1709 : :1710 : 3260262 : + if (!*buffer_size)1711 : : + {1712 : : + /*1713 : : + We are requested to determine how much memory we need.1714 : : + Request memory to finish the scan in one pass but do not request1715 : : + more than @@mrr_buff_size.1716 : : + */1717 : 5281504 : + *buffer_size= (uint) MY_MIN(extra_mem_overhead + elem_size*(ulong)rows,1718 : : + MY_MAX(table->in_use->variables.mrr_buff_size,1719 : 2640752 : + extra_mem_overhead));1720 : : + }1721 : : +1722 : 3260262 : + if (elem_size + extra_mem_overhead > *buffer_size)1723 : 8 : return TRUE; /* Buffer has not enough space for even 1 rowid */1724 : :1725 : 3260254 : + max_buff_entries = (*buffer_size - extra_mem_overhead) / elem_size;1726 : : +1727 : : /* Number of iterations we'll make with full buffer */1728 : 3260254 : n_full_steps= (uint)floor(rows2double(rows) / max_buff_entries);1729 : :===== File: sql/multi_range_read.h =====631 : :632 : : bool choose_mrr_impl(uint keyno, ha_rows rows, uint *flags, uint *bufsz,633 : : Cost_estimate *cost);634 : : + bool get_disk_sweep_mrr_cost(uint keynr, ha_rows rows, uint flags,635 : : + uint *buffer_size, uint extra_mem_overhead,636 : : + Cost_estimate *cost);637 : : bool check_cpk_scan(THD *thd, TABLE_SHARE *share, uint keyno, uint mrr_flags);638 : :639 : : bool setup_buffer_sharing(uint key_size_in_keybuf, key_part_map key_tuple_map);===== File: storage/innobase/handler/ha_innodb.cc =====6466 : 60912 : DBUG_ENTER("ha_innobase::clone");6467 : :6468 : : ha_innobase* new_handler = static_cast<ha_innobase*>(6469 : 30456 : + handler::clone(m_prebuilt->table->name.m_name, mem_root));6470 : :6471 : 30456 : if (new_handler != NULL) {6472 : 30456 : DBUG_ASSERT(new_handler->m_prebuilt != NULL);===== File: storage/maria/ha_maria.cc =====1000 : 4864300 : {}1001 : :1002 : :1003 : 96627 : +handler *ha_maria::clone(const char *name __attribute__((unused)),1004 : : + MEM_ROOT *mem_root)1005 : : {1006 : : + ha_maria *new_handler=1007 : 96627 : + static_cast <ha_maria *>(handler::clone(file->s->open_file_name.str,1008 : 96627 : + mem_root));1009 : 96627 : if (new_handler)1010 : : {1011 : 96627 : new_handler->file->state= file->state;===== File: storage/myisam/ha_myisam.cc =====702 : 3851265 : can_enable_indexes(1)703 : 3851099 : {}704 : :705 : 73231 : +handler *ha_myisam::clone(const char *name __attribute__((unused)),706 : : + MEM_ROOT *mem_root)707 : : {708 : : + ha_myisam *new_handler=709 : 73231 : + static_cast <ha_myisam *>(handler::clone(file->filename, mem_root));710 : 73231 : if (new_handler)711 : 73231 : new_handler->file->state= file->state;712 : 73231 : return new_handler;Which of course doesn't mean much, apart from the obviously missing parts
sql/ha_partition.cc:5485 : + if ((tmp= (*file)->ha_rnd_end()))5486 : + error= tmp;and
1592 : 3260248 : + if (get_disk_sweep_mrr_cost(keyno, rows, *flags, bufsz, add_len,1593 : : + &dsmrr_cost))1594 : 0 : return TRUE;