Out of curiosity, why are you recalculating subschemas on queries? It seems like you might be able to cache the schema information on initial source add, and then use DB event triggers to cause a recalculation on schema change
On Thu, Jun 9, 2022 at 11:25 PM itxiangkui (Jira) <[email protected]> wrote: > itxiangkui created CALCITE-5187: > ----------------------------------- > > Summary: "CalciteSchema call getSubSchemaMap when prepareSql" > will Causes SQL execution to slow down > Key: CALCITE-5187 > URL: https://issues.apache.org/jira/browse/CALCITE-5187 > Project: Calcite > Issue Type: Improvement > Reporter: itxiangkui > Attachments: Screenshot from 2022-06-10 11-17-02.png, Screenshot > from 2022-06-10 11-18-54.png > > > > > # We define the structure of Schema-Tree: catalog->database->table > # 2. A time series database is designed. Schema information is stored in > the traditional Mysql database. Therefore, methods such as > Schema.getSubSchemaNames() Schema.getSubSchemaMap() will be frequently > called when executing SQL, especially in the validate phase. > # Query a SQL sample as follows: > select * from `catalog`.`database`.`xxtable` limit 10 > # Modified part of the code and connected to the opentracing system > (jaeger) > # DEBUG tracks and analyzes the entire execution process of SQL to > analyze why it is slow, so as to optimize our system > > Here is one of our SQL executions: > > !Screenshot from 2022-06-10 11-18-54.png! > > > > Apparently, ICUserCatalogSchema.getSubSchemaMap() is called many times and > it increases with the number of databases > The debug code finds that the prepareSql stage will call the > gatherLattices method, and gatherLattices will access all Schema > information, which corresponds to databases > > > {code:java} > private static void gatherLattices(CalciteSchema schema, > List<CalciteSchema.LatticeEntry> list) { > list.addAll(schema.getLatticeMap().values()); > for (CalciteSchema subSchema : schema.getSubSchemaMap().values()) { > gatherLattices(subSchema, list); > } > } {code} > My question is, why do you care about other database information when > querying a table, and are there any suggestions for improvement here... > > > > > > -- > This message was sent by Atlassian Jira > (v8.20.7#820007) >
