Consider choosing block strategy for slog-async

[overvenus]

Question

There are lot of slog-async: logger dropped messages due to channel overflow, count: 7 in tikv's log file. The count: 7 means 7 logs have been drop due to slogger channel full. There is no way to recover dropped logs, which is not helpful for debugging. The behaviour is controlled by slog_async::OverflowStrategy. Instead of OverflowStrategy::DropAndReport(current strategy), please consider choosing OverflowStrategy::Block, so tikv prints all logs.

[Hoverbear]

Already fixed in master quite some time ago:

tikv/src/bin/util/setup.rs

Lines 39 to 62 in d046fae

	const SLOG_CHANNEL_OVERFLOW_STRATEGY: OverflowStrategy = OverflowStrategy::Block;
	macro_rules! fatal {
	($lvl:expr, $($arg:tt)+) => ({
	if LOG_INITIALIZED.load(Ordering::SeqCst) {
	error!($lvl, $($arg)+);
	} else {
	eprintln!($lvl, $($arg)+);
	}
	process::exit(1)
	})
	}
	#[allow(dead_code)]
	pub fn init_log(config: &TiKvConfig) -> GlobalLoggerGuard {
	let log_rotation_timespan = chrono::Duration::from_std(
	config.log_rotation_timespan.clone().into(),
	).expect("config.log_rotation_timespan is an invalid duration.");
	let guard = if config.log_file.is_empty() {
	let decorator = TermDecorator::new().build();
	let drain = logger::TikvFormat::new(decorator).fuse();
	let drain = Async::new(drain)
	.chan_size(SLOG_CHANNEL_SIZE)
	.overflow_strategy(SLOG_CHANNEL_OVERFLOW_STRATEGY)

[overvenus]

Block strategy only appiles to term-slogger. file-slogger still uses OverflowStrategy::DropAndReport.

[Hoverbear]

Ah, of course!

[hicqu]

Why not remove redudant logs? For example, CompactLog is print too frequently.

[Hoverbear]

@hicqu We don't ever want to drop logs (this is a bug). Removing redundant logs is a feature request, and can have it's own issue. :)