added comments to the configs updated

Author: nikhilsinhaparseable

src/cli.rs

@@ -260,7 +260,8 @@ pub struct Options {
         help = "Set a fixed memory limit for query in GiB"
     )]
     pub query_memory_pool_size: Option<usize>,
-
+    // reduced the max row group size from 1048576
+    // smaller row groups help in faster query performance in multi threaded query
     #[arg(
         long,
         env = "P_PARQUET_ROW_GROUP_SIZE",

src/query/mod.rs

@@ -88,11 +88,12 @@ impl Query {
         let runtime_config = runtime_config.with_memory_limit(pool_size, fraction);
         let runtime = Arc::new(runtime_config.build().unwrap());
 
+        // All the config options are explained here - 
+        // https://datafusion.apache.org/user-guide/configs.html
         let mut config = SessionConfig::default()
             .with_parquet_pruning(true)
             .with_prefer_existing_sort(true)
             .with_batch_size(1000000);
-        // For more details refer https://datafusion.apache.org/user-guide/configs.html
 
         // Pushdown filters allows DF to push the filters as far down in the plan as possible
         // and thus, reducing the number of rows decoded