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Expose InnoDB's Adaptive Hash Index (AHI) statistics through ANALYZE FORMAT=JSON output and global status variables to provide query-level and system-level visibility into AHI usage and effectiveness. This allows DBAs and developers to monitor how well the adaptive hash index is serving their workloads on a per-query basis. The r_ahi_stats object (nested inside r_engine_stats) now reports four key metrics: ahi_searches (successful AHI lookups), ahi_searches_btree (AHI misses requiring B-tree fallback), ahi_rows_added (rows inserted into AHI), and ahi_pages_added (pages indexed by AHI). These same metrics are exposed globally via innodb_status_variables. Transaction-local tracking eliminates contention by accumulating statistics in trx_t fields (n_sea, n_non_sea, n_ahi_rows_added, n_ahi_pages_added) and aggregating them into global atomic counters during trx_t::commit_cleanup() and trx_t::free(), following the pattern established for buf_pool.stat.n_page_gets. AHI counters are now organized as data members of the btr_sea structure where they logically belong, using anonymous unions to enable both atomic writes and direct non-atomic reads. - btr_ahi_inc_searches(): Increment trx->n_sea when AHI lookup succeeds. - btr_ahi_inc_searches_btree(): Increment trx->n_non_sea when AHI lookup fails and falls back to B-tree search. - btr_ahi_inc_rows_added(): Increment trx->n_ahi_rows_added when rows are added to the adaptive hash index structure. - btr_ahi_inc_pages_added(): Increment trx->n_ahi_pages_added when new pages are indexed by AHI. - btr_cur_t::search_leaf(): Call btr_ahi_inc_searches() on successful AHI hit and btr_ahi_inc_searches_btree() on AHI miss. - btr_sea: Add four counter members with anonymous unions to allow atomic writes and lockless reads: hit_count/hit_count_nonatomic (successful AHI lookups), miss_count/miss_count_nonatomic (B-tree searches after AHI miss), rows_added/rows_added_nonatomic (rows added to AHI), and pages_added/pages_added_nonatomic (pages added to AHI). Also includes hit_count_old and miss_count_old variant for computing deltas in monitor output. - btr0cur.h/btr0cur.cc: Remove global declarations and definitions of btr_cur_n_sea, btr_cur_n_non_sea, btr_cur_n_sea_old, btr_cur_n_non_sea_old, btr_ahi_n_rows_added, and btr_ahi_n_pages_added as they are now data members of btr_sea. - export_var_t: Remove innodb_ahi_hit, innodb_ahi_miss, innodb_ahi_rows_added, and innodb_ahi_pages_added members. MySQL status variables now point directly to btr_search counters. - innodb_status_variables[]: Change AHI status variable pointers from &export_vars.innodb_ahi_* to &btr_search.*_nonatomic, enabling zero-copy reads: adaptive_hash_hash_searches points to &btr_search.hit_count_nonatomic, adaptive_hash_non_hash_searches to &btr_search.miss_count_nonatomic, adaptive_hash_rows_added to &btr_search.rows_added_nonatomic, and adaptive_hash_pages_added to &btr_search.pages_added_nonatomic. - MONITOR_OVLD_ADAPTIVE_HASH_ROW_ADDED, MONITOR_OVLD_ADAPTIVE_HASH_PAGE_ADDED: Convert monitor counters to "overload" type that read from atomic counters btr_search.rows_added and btr_search.pages_added respectively instead of maintaining separate statistics. - trx_t::commit_cleanup() and trx_t::free(): Update transaction cleanup to increment btr_search.hit_count, btr_search.miss_count, btr_search.rows_added, and btr_search.pages_added instead of the old global counters. - trace_engine_stats(): Output r_ahi_stats object with all four AHI counters in JSON format when any AHI activity is detected during query execution. - ha_handler_stats: Added ahi_searches, ahi_searches_btree, ahi_rows_added, and ahi_pages_added fields to track per-query AHI statistics. - Add mtr parameter to btr_search_move_or_delete_hash_entries(), btr_cur_t::search_info_update(), btr_search_update_hash_on_insert(), btr_search_update_hash_ref(), btr_search_info_update_hash(), and btr_search_build_page_hash_index() to allow updating AHI statistics. - ahi_stats.test: Comprehensive verification of AHI statistics reporting across different scenarios: insufficient accesses (no AHI build), threshold triggering (AHI construction), heavy warmup (full AHI utilization), and disabled AHI (verify zero statistics). - check_ahi_status.inc: Reusable include file for executing queries with configurable warmup repetitions and extracting AHI statistics from ANALYZE FORMAT=JSON output using JSON path expressions.
97 lines
2.8 KiB
C++
97 lines
2.8 KiB
C++
#ifndef HA_HANDLER_STATS_INCLUDED
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#define HA_HANDLER_STATS_INCLUDED
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/*
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Copyright (c) 2023, MariaDB Foundation
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; version 2 of
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the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA
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*/
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/* Definitions for parameters to do with handler-routines */
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class ha_handler_stats
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{
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public:
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ulonglong pages_accessed; /* Pages accessed from page cache */
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ulonglong pages_updated; /* Pages changed in page cache */
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ulonglong pages_read_count; /* Pages read from disk */
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/* Time spent reading pages, in timer_tracker_frequency() units */
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ulonglong pages_read_time;
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/*
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Number of pages that we've requested to prefetch while running the query.
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Note that we don't know:
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- how much time was spent reading these pages (and how to count the time
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if reading was done in parallel)
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- whether the pages were read by "us" or somebody else...
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*/
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ulonglong pages_prefetched;
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ulonglong undo_records_read;
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ulonglong ahi_searches; /* Successful adaptive hash lookups */
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ulonglong ahi_searches_btree; /* B-tree searches (AHI miss) */
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ulonglong ahi_rows_added; /* Rows added to adaptive hash index */
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ulonglong ahi_pages_added; /* Pages added to adaptive hash index */
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/* Time spent in engine, in timer_tracker_frequency() units */
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ulonglong engine_time;
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/*
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Index Condition Pushdown: number of times condition was checked for index
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tuple
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*/
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ulonglong icp_attempts;
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/*
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Index Condition Pushdown: number of times condition check evaluated to TRUE
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*/
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ulonglong icp_match;
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uint active; /* <> 0 if status has to be updated */
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ha_handler_stats()
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{
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active= 0;
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}
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#define first_stat pages_accessed
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#define last_stat icp_match
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inline void reset()
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{
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bzero((void*) this, sizeof(*this));
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}
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inline void add(ha_handler_stats *stats)
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{
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ulonglong *to= &first_stat;
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ulonglong *from= &stats->first_stat;
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do
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{
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(*to)+= *from++;
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} while (to++ != &last_stat);
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}
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inline bool has_stats()
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{
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if (!active)
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return 0;
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ulonglong *to= &first_stat;
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do
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{
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if (*to)
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return 1;
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} while (to++ != &last_stat);
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return 0;
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}
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};
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#endif /* HA_HANDLER_STATS_INCLUDED */
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