[jira] [Commented] (COUCHDB-887) _log handler has very odd semantics for bytes/offset, probably a bug
[ https://issues.apache.org/jira/browse/COUCHDB-887?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13139993#comment-13139993 ] Nuutti Kotivuori commented on COUCHDB-887: -- Even your explanation is not really exact. What it does is (abstractly): - start reading from the end - seek `bytes` backwards from the end - seek `offset` bytes forward into the file - read until a maximum of `bytes` bytes is returned - stop The result is that: - bytes=1offset=1000 - returns last 9000 bytes of log file - bytes=9000 - returns last 9000 bytes of log file Like I said in the bug report, the results are 100% equivalent of just doing 'bytes - offset' on the clientside before making the request, except for the case of 'offset = bytes', in which case EOF is returned because of the attempt to read past file end. In general, I'm having trouble figuring out what the original motivation behind offset is... I mean, *if* it would seek backwards, you could theoretically get the last 100kB of log in 1kB chunks by doing repeated queries with bytes=1024 and incrementing offset by 1024 each time - but in practice the log file grows between each request, so there'll be lots of repeated lines and such. _log handler has very odd semantics for bytes/offset, probably a bug Key: COUCHDB-887 URL: https://issues.apache.org/jira/browse/COUCHDB-887 Project: CouchDB Issue Type: Bug Components: HTTP Interface Affects Versions: 0.11, 0.11.1, 0.11.2, 1.0, 1.0.1 Reporter: Nuutti Kotivuori Priority: Trivial Attachments: couch_log.erl.diff The _log method for couchdb servers has query arguments bytes and offset, but they seem to behave really weirdly. If offset = bytes, an eof error is returned - otherwise offset is just substracted from bytes and the request behaves identically otherwise. A simple fix to the expected behaviour is included - offset counts backwards from bytes. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (COUCHDB-887) _log handler has very odd semantics for bytes/offset, probably a bug
[ https://issues.apache.org/jira/browse/COUCHDB-887?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13140013#comment-13140013 ] Nuutti Kotivuori commented on COUCHDB-887: -- Sorry, I'm having a hard time finding the commit anywhere. I'd like to check if the new logic sounds reasonable to me too :-) _log handler has very odd semantics for bytes/offset, probably a bug Key: COUCHDB-887 URL: https://issues.apache.org/jira/browse/COUCHDB-887 Project: CouchDB Issue Type: Bug Components: HTTP Interface Affects Versions: 0.11, 0.11.1, 0.11.2, 1.0, 1.0.1 Reporter: Nuutti Kotivuori Priority: Trivial Fix For: 1.2, 1.3 Attachments: couch_log.erl.diff The _log method for couchdb servers has query arguments bytes and offset, but they seem to behave really weirdly. If offset = bytes, an eof error is returned - otherwise offset is just substracted from bytes and the request behaves identically otherwise. A simple fix to the expected behaviour is included - offset counts backwards from bytes. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (COUCHDB-887) _log handler has very odd semantics for bytes/offset, probably a bug
[ https://issues.apache.org/jira/browse/COUCHDB-887?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13140014#comment-13140014 ] Jan Lehnardt commented on COUCHDB-887: -- http://git-wip-us.apache.org/repos/asf?p=couchdb.git;a=blobdiff;f=src/couchdb/couch_log.erl;h=1b05f4db64084ac405dd9e75b6d7bdc18e9fcda2;hp=0befe7aabfc79dc1047d044b1e002a3368789e68;hb=ad700014;hpb=7809f3ca844da984ebf1a90deefa2b4ab83d289e _log handler has very odd semantics for bytes/offset, probably a bug Key: COUCHDB-887 URL: https://issues.apache.org/jira/browse/COUCHDB-887 Project: CouchDB Issue Type: Bug Components: HTTP Interface Affects Versions: 0.11, 0.11.1, 0.11.2, 1.0, 1.0.1 Reporter: Nuutti Kotivuori Priority: Trivial Fix For: 1.2, 1.3 Attachments: couch_log.erl.diff The _log method for couchdb servers has query arguments bytes and offset, but they seem to behave really weirdly. If offset = bytes, an eof error is returned - otherwise offset is just substracted from bytes and the request behaves identically otherwise. A simple fix to the expected behaviour is included - offset counts backwards from bytes. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (COUCHDB-887) _log handler has very odd semantics for bytes/offset, probably a bug
[ https://issues.apache.org/jira/browse/COUCHDB-887?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13140025#comment-13140025 ] Nuutti Kotivuori commented on COUCHDB-887: -- Okay thanks, looks good. The repeated line issue is still present, but that is an entirely separate issue. _log handler has very odd semantics for bytes/offset, probably a bug Key: COUCHDB-887 URL: https://issues.apache.org/jira/browse/COUCHDB-887 Project: CouchDB Issue Type: Bug Components: HTTP Interface Affects Versions: 0.11, 0.11.1, 0.11.2, 1.0, 1.0.1 Reporter: Nuutti Kotivuori Priority: Trivial Fix For: 1.2, 1.3 Attachments: couch_log.erl.diff The _log method for couchdb servers has query arguments bytes and offset, but they seem to behave really weirdly. If offset = bytes, an eof error is returned - otherwise offset is just substracted from bytes and the request behaves identically otherwise. A simple fix to the expected behaviour is included - offset counts backwards from bytes. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (COUCHDB-887) _log handler has very odd semantics for bytes/offset, probably a bug
[ https://issues.apache.org/jira/browse/COUCHDB-887?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13140029#comment-13140029 ] Jan Lehnardt commented on COUCHDB-887: -- Yeah, I decided that that's not worth fixing. The motivation is a poor-man's tail -f over HTTP and I think we have that now :) _log handler has very odd semantics for bytes/offset, probably a bug Key: COUCHDB-887 URL: https://issues.apache.org/jira/browse/COUCHDB-887 Project: CouchDB Issue Type: Bug Components: HTTP Interface Affects Versions: 0.11, 0.11.1, 0.11.2, 1.0, 1.0.1 Reporter: Nuutti Kotivuori Priority: Trivial Fix For: 1.2, 1.3 Attachments: couch_log.erl.diff The _log method for couchdb servers has query arguments bytes and offset, but they seem to behave really weirdly. If offset = bytes, an eof error is returned - otherwise offset is just substracted from bytes and the request behaves identically otherwise. A simple fix to the expected behaviour is included - offset counts backwards from bytes. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] Commented: (COUCHDB-887) _log handler has very odd semantics for bytes/offset, probably a bug
[ https://issues.apache.org/jira/browse/COUCHDB-887?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12909083#action_12909083 ] Randall Leeds commented on COUCHDB-887: --- Your patch reverses the semantics of offset, but it's not clear that one is more right. If your intuition about offet being a negative from the end is right, then I'd expect: Start = lists:max([LogFileSize - Offset]) where Bytes determines how many bytes to read, but has no effect on where reading begins. However, in either case I think you're right that Bytes should be passed to file:pread/3 instead of LogFileSize. _log handler has very odd semantics for bytes/offset, probably a bug Key: COUCHDB-887 URL: https://issues.apache.org/jira/browse/COUCHDB-887 Project: CouchDB Issue Type: Bug Components: HTTP Interface Affects Versions: 0.11, 0.11.1, 0.11.2, 1.0, 1.0.1 Reporter: Nuutti Kotivuori Priority: Trivial Attachments: couch_log.erl.diff The _log method for couchdb servers has query arguments bytes and offset, but they seem to behave really weirdly. If offset = bytes, an eof error is returned - otherwise offset is just substracted from bytes and the request behaves identically otherwise. A simple fix to the expected behaviour is included - offset counts backwards from bytes. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
[jira] Commented: (COUCHDB-887) _log handler has very odd semantics for bytes/offset, probably a bug
[ https://issues.apache.org/jira/browse/COUCHDB-887?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12909103#action_12909103 ] Nuutti Kotivuori commented on COUCHDB-887: -- The *current* semantics of offset are such, that there is really no point in specifying it, ever, as one can just supply a smaller bytes value to get the same effect. If offset is simply substracted from LogFileSize, then offset *must* atleast default to bytes, or otherwise the result is always eof. _log handler has very odd semantics for bytes/offset, probably a bug Key: COUCHDB-887 URL: https://issues.apache.org/jira/browse/COUCHDB-887 Project: CouchDB Issue Type: Bug Components: HTTP Interface Affects Versions: 0.11, 0.11.1, 0.11.2, 1.0, 1.0.1 Reporter: Nuutti Kotivuori Priority: Trivial Attachments: couch_log.erl.diff The _log method for couchdb servers has query arguments bytes and offset, but they seem to behave really weirdly. If offset = bytes, an eof error is returned - otherwise offset is just substracted from bytes and the request behaves identically otherwise. A simple fix to the expected behaviour is included - offset counts backwards from bytes. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
