-Removed default value for max_days option

+Adding note about query performance

chan-like/src/main.rs

@@ -11,7 +11,7 @@ use clap::{App, Arg};
 
 
 const MAX_DAYS_HELP: &'static str = "Purge messages older than <D> days old
-If the value is 0 (default) then messages are not deleted by their age
+If the value is 0  then messages are not deleted by their age
 ";
 
 const MSG_LIMIT_HELP: &'static str = "Sets the max number of messages per channel.
@@ -42,9 +42,19 @@ async fn remove_old(pool: &Pool, age_limit: i64) -> Result<(), mysql_async::Erro
     }
 }
 async fn remove_maxed(pool: &Pool, max_msg: u64) -> Result<(), mysql_async::Error> {
-    // grab each channel id
+
-    // remove max by group
+    // For N channels we're going to do n+1 queries making this really expensive
-    // ?
+    // TODO: reduce this to a single query for reasons below: tags[network, sql, slow]
+    /*
+     * Multiple network hits blow(moreso if the the db is located away from the
+     * main server binary but i digress.
+     * The first hit is no the expensive part if I'm being honest,
+     * It's everything after that leverages the channel id's as the messages
+     * table is likely to be filled with a ton of shit.
+     *
+     * The trick is going to be in some really nasty group by/limit thing but 
+     * frankly this works for now so into the backlog it goes
+     */
     let mut conn = pool.get_conn().await?;
     let channel_ids: Vec<u64> = conn.exec_map(
         "SELECT id FROM channels", (),
@@ -81,8 +91,7 @@ async fn main() -> Result<(), String>{
              .long("max-days")
              .value_name("D")
              .takes_value(true)
-             .long_help(MAX_DAYS_HELP)
+             .long_help(MAX_DAYS_HELP))
-             .default_value("0"))
         .arg(Arg::with_name("config_file")
              .short("f")
              .long("file")