perf: drop db handles that are not quickly read

This commit is contained in:
Greg Heartsfield 2022-12-19 00:02:28 -06:00
parent 8c013107f9
commit 2cfd384339

View File

@ -655,8 +655,12 @@ pub async fn db_query(
log_pool_stats(&pool);
// cutoff for displaying slow queries
let slow_cutoff = Duration::from_millis(2000);
// any client that doesn't cause us to generate new rows in 5
// seconds gets dropped.
let abort_cutoff = Duration::from_secs(5);
let start = Instant::now();
let mut slow_first_event;
let mut last_successful_send = Instant::now();
if let Ok(conn) = pool.get() {
// execute the query. Don't cache, since queries vary so much.
let mut stmt = conn.prepare(&q)?;
@ -704,12 +708,33 @@ pub async fn db_query(
}
row_count += 1;
let event_json = row.get(0)?;
loop {
if query_tx.capacity() != 0 {
// we have capacity to add another item
break;
} else {
// the queue is full
trace!("db reader thread is stalled");
if last_successful_send + abort_cutoff < Instant::now() {
// the queue has been full for too long, abort
info!("aborting database query due to slow client");
let ok: Result<()> = Ok(());
return ok;
}
// give the queue a chance to clear before trying again
thread::sleep(Duration::from_millis(100));
}
}
// TODO: we could use try_send, but we'd have to juggle
// getting the query result back as part of the error
// result.
query_tx
.blocking_send(QueryResult {
sub_id: sub.get_id(),
event: event_json,
})
.ok();
last_successful_send = Instant::now();
}
query_tx
.blocking_send(QueryResult {