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049d839350
* preserve the graph in memory between statements * keep it in a TABLE_SHARE, available for concurrent searches * nodes are generally read-only, walking the graph doesn't change them * distance to target is cached, calculated only once * SIMD-optimized bloom filter detects visited nodes * nodes are stored in an array, not List, to better utilize bloom filter * auto-adjusting heuristic to estimate the number of visited nodes (to configure the bloom filter) * many threads can concurrently walk the graph. MEM_ROOT and Hash_set are protected with a mutex, but walking doesn't need them * up to 8 threads can concurrently load nodes into the cache, nodes are partitioned into 8 mutexes (8 is chosen arbitrarily, might need tuning) * concurrent editing is not supported though * this is fine for MyISAM, TL_WRITE protects the TABLE_SHARE and the graph (note that TL_WRITE_CONCURRENT_INSERT is not allowed, because an INSERT into the main table means multiple UPDATEs in the graph) * InnoDB uses secondary transaction-level caches linked in a list in in thd->ha_data via a fake handlerton * on rollback the secondary cache is discarded, on commit nodes from the secondary cache are invalidated in the shared cache while it is exclusively locked * on savepoint rollback both caches are flushed. this can be improved in the future with a row visibility callback * graph size is controlled by @@mhnsw_cache_size, the cache is flushed when it reaches the threshold |
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| atomic | ||
| binlog | ||
| binlog_encryption | ||
| client | ||
| compat | ||
| csv | ||
| encryption | ||
| engines | ||
| events | ||
| federated | ||
| funcs_1 | ||
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| galera | ||
| galera_3nodes | ||
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| galera_sr | ||
| gcol | ||
| handler | ||
| heap | ||
| innodb | ||
| innodb_fts | ||
| innodb_gis | ||
| innodb_i_s | ||
| innodb_zip | ||
| jp | ||
| json | ||
| large_tests | ||
| maria | ||
| mariabackup | ||
| merge | ||
| mtr/t | ||
| mtr2 | ||
| multi_source | ||
| optimizer_unfixed_bugs | ||
| parts | ||
| perfschema | ||
| perfschema_stress | ||
| period | ||
| plugins | ||
| roles | ||
| rpl | ||
| s3 | ||
| sql_sequence | ||
| storage_engine | ||
| stress | ||
| sys_vars | ||
| sysschema | ||
| unit | ||
| vcol | ||
| versioning | ||
| wsrep | ||