Hi, Good feature! PB_Tree could be PBTree.
Thanks, ————————————————— Jialin Qiao Apache IoTDB PMC 周钰坤 <[email protected]> 于2023年6月19日周一 15:08写道： > > Hi, > > We're going to introduce PB Tree (Prefix-B+ Tree), a new SchemaEgnine > mode, in V1.2.0, which supports evict temporarily useless schema to > disk and load them back in need at runtime. With PB Tree, users will > not suffer from memory constraint for schema management any more, > especially in scenarios with massive time series. > > To enable PB Tree in IoTDB, the value of parameter named > schema_engine_mode in iotdb-commons.properties should be configured as > PB_Tree [1]. All the memory allocated for SchemaRegion will be used by > PB Tree. The allocation can be modified by changing the value of > parameters named storage_query_schema_consensus_free_memory_proportion > and schema_memory_proportion in iotdb-commons.properties. > > PB Tree is a new implementation of MTree in SchemaRegion, consisting > of a a PB Tree file and a prefix-tree-structured cache. The PB Tree > file manages the prefix tree structure on disk by storing pointer > pointing to first disk page storing children nodes in each node > record. B+ Tree is used to manage brother nodes for fast single child > node search. The cache is similar to the existing MTree implementation > in SchemaRegion. The main difference is that the children of a node > may not cached in memory, which should be read from disk by searching > specific B+ Tree located by pointer stored in node record and cached > in memory node object. > > Reference: > [1] > https://iotdb.apache.org/zh/UserGuide/V1.2.x/Reference/Common-Config-Manual.html#%E5%85%83%E6%95%B0%E6%8D%AE%E5%BC%95%E6%93%8E%E9%85%8D%E7%BD%AE > > Thanks. > ____________________ > Yunkun Zhou > Apache IoTDB Committer
