In PARTITIONED mode SQL queries are executed over each node’s primary partitions only.
Here is more information about distributed joins: https://apacheignite-sql.readme.io/docs/distributed-joins From: Prasad Bhalerao <[email protected]> Sent: Saturday, October 26, 2019 12:25 AM To: [email protected] Subject: Re: Query execution in ignite Question is specifically about primary and secondary partitions. So in case of replicated cache ignite scans primary and secondary partitions of any one of the node of the cluster to to fetch the data. But is it the case with partitioned cache. I mean in case of partitioned cache when SQL is executed, does ignite scan primary as well as secondary partitions of each node in the cluster or it just scans primary partitions of all the nodes in the cluster as the query is being executed on all nodes? On Fri 25 Oct, 2019, 10:46 PM <[email protected] <mailto:[email protected]> wrote: Hi, If a query is executed against a fully REPLICATED data then Ignite will send it to a single cluster node and run it over the local data there. if a query is executed over a PARTITIONED data, then the execution flow will be the following: The query will be parsed and split into multiple map queries and a single reduce query. * All the map queries are executed on all the nodes where required data resides. * All the nodes provide result sets of local execution to the query initiator (reducer) that, in turn, will accomplish the reduce phase by properly merging provided result sets. More information here: https://apacheignite-sql.readme.io/docs/how-ignite-sql-works Thanks, Alex From: Prasad Bhalerao <[email protected] <mailto:[email protected]> > Sent: Friday, October 25, 2019 1:31 AM To: [email protected] <mailto:[email protected]> Subject: Query execution in ignite Hi, When SQL is executed, does ignite always scan only primary partitions of all available nodes in cluster irrespective of cache mode partitioned or replicated? Thanks , Prasad
