log error when ReadEntryProcessor IOException

[AnonHxy]

Descriptions of the changes in this PR:

Motivation

Change the log-level to error when ReadEntryProcessor throw IOException. The reason is that:

1. IOException should not happen frequently，so the error log will not print too much
2. It will be convenient for troubleshooting if we print the error log.
3. Also we can see that ReadEntryProcessorV3 has printed the error log

bookkeeper/bookkeeper-server/src/main/java/org/apache/bookkeeper/proto/ReadEntryProcessorV3.java

Lines 233 to 236 in dc2bb1d

	} catch (IOException e) {
	LOG.error("IOException while reading entry: {} from ledger {} ", entryId, ledgerId, e);
	return buildResponse(readResponse, StatusCode.EIO, startTimeSw);
	} catch (BookieException.DataUnknownException e) {

Changes

log.debug -> log.error

[merlimat]

I believe this would print the whole stack trace every time a client gets a connectivity error with any bookie, for each entry that we're trying to read.

[AnonHxy]

whole stack trace every time a client gets a connectivity error with any bookie

Thanks for your review @merlimat . But I don't get your point. This method runs only on serever side and probability throw IOException if read an entry from storage. So I think it doesn't matter with client print logs

[hangc0276]

Pring ledgerId:entryId instead of the whole request content?

[AnonHxy]

I think print whole request is OK. because ReadRequest has overwrite the toString method:

bookkeeper/bookkeeper-server/src/main/java/org/apache/bookkeeper/proto/BookieProtocol.java

Lines 249 to 251 in 34bd4b3

	public String toString() {
	return String.format("Op(%d)[Ledger:%d,Entry:%d]", opCode, ledgerId, entryId);
	}

@hangc0276

[hangc0276]

I believe this would print the whole stack trace every time a client gets a connectivity error with any bookie, for each entry that we're trying to read.

If the target entry does not exist on the bookie, it will throw NoLedgerException or NoEntryException and won't go into this code path. @merlimat Do you have any concern?

[horizonzy]

I believe this would print the whole stack trace every time a client gets a connectivity error with any bookie, for each entry that we're trying to read.

If the target entry does not exist on the bookie, it will throw NoLedgerException or NoEntryException and won't go into this code path. @merlimat Do you have any concern?

The NoLedgerException and NoEntryException extend IOException, it should be caught.

[hangc0276]

Overall LGTM.

[horizonzy]

LGTM.

[hezhangjian]

@merlimat Could you please take a look again?