Thread

  1. Re: Regarding WAL Format Changes

    Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> — 2012-06-27T14:56:13Z

    On 27.06.2012 17:14, Amit Kapila wrote:
    > 1. Function header for following functions still contains referece to log,
    > seg
    >     a. InstallXLogFileSegment()
    >     b. RemoveOldXlogFiles()
    >     c. XLogFileCopy()
    >     d. XLogGetLastRemoved()
    >     e. UpdateLastRemovedPtr()
    >     f. RemoveOldXlogFiles()
    
    Thanks, fixed.
    
    > 2. @@ -2680,8 +2645,8 @@ InstallXLogFileSegment(uint32 *log, uint32 *seg,
    > char *tmppath,
    >                           LWLockRelease(ControlFileLock);
    >                   ereport(LOG,
    >                                   (errcode_for_file_access(),
    > -                                 errmsg("could not link file \"%s\" to
    > \"%s\" (initialization of log file %u, segment %u): %m",
    > -                                                tmppath, path, *log,
    > *seg)));
    > +                                 errmsg("could not link file \"%s\" to
    > \"%s\" (initialization of log file): %m",
    > +                                                tmppath, path)));
    >     If Changed error message can contain log file and segment number, it
    > would be more clear. That should be easily
    >     deducible from segment number.
    
    That seems redundant. The target file name is calculated from the 
    segment number, and we're now using the file name instead of log+seg in 
    other messages too.
    
    > 3.   -RemoveOldXlogFiles(uint32 log, uint32 seg, XLogRecPtr endptr)
    > +RemoveOldXlogFiles(XLogSegNo segno, XLogRecPtr endptr)
    > .
    > .
    > .
    > @@ -4016,8 +3953,9 @@ retry:
    >                           if (!(((XLogPageHeader) readBuf)->xlp_info&
    > XLP_FIRST_IS_CONTRECORD))
    >                           {
    >                                   ereport(emode_for_corrupt_record(emode,
    > *RecPtr),
    > -                                                (errmsg("there is no
    > contrecord flag in log file %u, segment %u, offset %u",
    > -                                                                readId,
    > readSeg, readOff)));
    > +                                                (errmsg("there is no
    > contrecord flag in log segment %s, offset %u",
    > +
    > XLogFileNameP(curFileTLI, readSegNo),
    > +                                                                readOff)));
    >
    >                                   goto next_record_is_invalid;
    >                           }
    >                           pageHeaderSize =
    > XLogPageHeaderSize((XLogPageHeader) readBuf);
    > @@ -4025,10 +3963,13 @@ retry:
    >                           if (contrecord->xl_rem_len == 0 ||
    >                                   total_len != (contrecord->xl_rem_len +
    > gotlen))
    >                           {
    > +                                char fname[MAXFNAMELEN];
    > +                                XLogFileName(fname, curFileTLI, readSegNo);
    >
    >                                   ereport(emode_for_corrupt_record(emode,
    > *RecPtr),
    > -                                                (errmsg("invalid contrecord
    > length %u in log file %u, segment %u, offset %u",
    > +                                                (errmsg("invalid contrecord
    > length %u in log segment %s, offset %u",
    >
    > contrecord->xl_rem_len,
    > -                                                                readId,
    > readSeg, readOff)));
    > +
    > XLogFileNameP(curFileTLI, readSegNo),
    > +                                                                readOff)));
    >
    >                                   goto next_record_is_invalid;
    >                           }
    >
    >    For the above 2 changed error messages, 'log segment' is used for
    > filename.
    >    However all similar changes has 'log file' for filename. There are some
    > places
    >    where 'log segment' is used and other places it is 'log file'.
    >    So is there any particular reason for it?
    
    Not really. There are several messages that use "log file %s", and also 
    several places that use "log segment %s" Should we make it consistent 
    and use either "log segment" or "log file" everywhere?
    
    > 4. @@ -533,33 +533,17 @@ pg_xlog_location_diff(PG_FUNCTION_ARGS)
    > -        /*
    > -         * Sanity check
    > -         */
    > -        if (loc1.xrecoff>  XLogFileSize)
    > -                ereport(ERROR,
    > -                                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
    > -                                 errmsg("xrecoff \"%X\" is out of valid
    > range, 0..%X", loc1.xrecoff, XLogFileSize)));
    > -        if (loc2.xrecoff>  XLogFileSize)
    > -                ereport(ERROR,
    > -                                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
    > -                                 errmsg("xrecoff \"%X\" is out of valid
    > range, 0..%X", loc2.xrecoff, XLogFileSize)));
    > +        bytes1 = (((uint64)loc1.xlogid)<<  32L) + loc1.xrecoff;
    > +        bytes2 = (((uint64)loc2.xlogid)<<  32L) + loc2.xrecoff;
    >
    >      Is there no chance that it can be out of valid range after new changes,
    > just a doubt?
    
    No. Not in the sense it used to be, anyway, the XLogFileSize check is no 
    longer relevant. Perhaps we should check for InvalidXLogRecPtr or that 
    the pointer doesn't point e.g in the middle of a page header. But then 
    again, this calculation works fine with both of those cases, so I see no 
    reason to make it stricter.
    
    > 5.
    > --- a/src/backend/replication/walreceiver.c
    > +++ b/src/backend/replication/walreceiver.c
    > @@ -69,11 +69,12 @@ walrcv_disconnect_type walrcv_disconnect = NULL;
    >
    >   /*
    >    * These variables are used similarly to openLogFile/Id/Seg/Off,
    > - * but for walreceiver to write the XLOG.
    > + * but for walreceiver to write the XLOG. recvFileTLI is the TimeLineID
    >
    > In the above comments, there is still reference to Id/Seg/Off.
    
    Thanks, fixed.
    
    -- 
       Heikki Linnakangas
       EnterpriseDB   http://www.enterprisedb.com
    
    
  2. Re: Regarding WAL Format Changes

    Alvaro Herrera <alvherre@commandprompt.com> — 2012-06-27T15:31:24Z

    Excerpts from Heikki Linnakangas's message of mié jun 27 10:56:13 -0400 2012:
    > On 27.06.2012 17:14, Amit Kapila wrote:
    
    > >    For the above 2 changed error messages, 'log segment' is used for
    > > filename.
    > >    However all similar changes has 'log file' for filename. There are some
    > > places
    > >    where 'log segment' is used and other places it is 'log file'.
    > >    So is there any particular reason for it?
    > 
    > Not really. There are several messages that use "log file %s", and also 
    > several places that use "log segment %s" Should we make it consistent 
    > and use either "log segment" or "log file" everywhere?
    
    I think it would be better to use "log segment" for WAL segments.  That
    way we don't cause confusion with the regular text/csv log output files.
    Heck, maybe even "WAL segment" instead of "log".
    
    As a translator, I can't have a single, clear explanation of what "log
    file" is because there are multiple meanings.  It would be better not to
    depend on context.
    
    -- 
    Álvaro Herrera <alvherre@commandprompt.com>
    The PostgreSQL Company - Command Prompt, Inc.
    PostgreSQL Replication, Consulting, Custom Development, 24x7 support
    
    
  3. Re: Regarding WAL Format Changes

    Fujii Masao <masao.fujii@gmail.com> — 2012-06-27T15:55:27Z

    On Wed, Jun 27, 2012 at 11:56 PM, Heikki Linnakangas
    <heikki.linnakangas@enterprisedb.com> wrote:
    > On 27.06.2012 17:14, Amit Kapila wrote:
    >>
    >> 1. Function header for following functions still contains referece to log,
    >> seg
    >>    a. InstallXLogFileSegment()
    >>    b. RemoveOldXlogFiles()
    >>    c. XLogFileCopy()
    >>    d. XLogGetLastRemoved()
    >>    e. UpdateLastRemovedPtr()
    >>    f. RemoveOldXlogFiles()
    >
    >
    > Thanks, fixed.
    
    There is still reference to log/seg in the comment of InstallXLogFileSegment().
    The attached patch should be applied?
    
    Regards,
    
    -- 
    Fujii Masao
    
  4. Re: Regarding WAL Format Changes

    Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> — 2012-06-27T16:13:42Z

    On 27.06.2012 18:55, Fujii Masao wrote:
    > On Wed, Jun 27, 2012 at 11:56 PM, Heikki Linnakangas
    > <heikki.linnakangas@enterprisedb.com>  wrote:
    >> On 27.06.2012 17:14, Amit Kapila wrote:
    >>>
    >>> 1. Function header for following functions still contains referece to log,
    >>> seg
    >>>     a. InstallXLogFileSegment()
    >>>     b. RemoveOldXlogFiles()
    >>>     c. XLogFileCopy()
    >>>     d. XLogGetLastRemoved()
    >>>     e. UpdateLastRemovedPtr()
    >>>     f. RemoveOldXlogFiles()
    >>
    >>
    >> Thanks, fixed.
    >
    > There is still reference to log/seg in the comment of InstallXLogFileSegment().
    > The attached patch should be applied?
    
    Thanks, applied. Sorry for being so sloppy with this..
    
    -- 
       Heikki Linnakangas
       EnterpriseDB   http://www.enterprisedb.com
    
    
  5. Re: Regarding WAL Format Changes

    Tom Lane <tgl@sss.pgh.pa.us> — 2012-06-27T16:16:15Z

    Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> writes:
    >> So is there any particular reason for it?
    
    > Not really. There are several messages that use "log file %s", and also 
    > several places that use "log segment %s" Should we make it consistent 
    > and use either "log segment" or "log file" everywhere?
    
    +1 for uniformity.  I think I'd vote for using "file" and eliminating
    the "segment" terminology altogether, but the other direction would be
    okay too, and might require fewer changes.
    
    IIRC, in the original coding "segment" meant 16MB worth of WAL while
    "file" was sometimes used to denote 4GB worth (ie, the boundaries where
    we had to increment the high half of the LSN struct).  Now that 4GB
    boundaries are not special, there's no reason to retain the "file"
    concept or terminology.
    
    			regards, tom lane
    
    
  6. Re: Regarding WAL Format Changes

    Fujii Masao <masao.fujii@gmail.com> — 2012-06-27T17:26:38Z

    On Thu, Jun 28, 2012 at 1:13 AM, Heikki Linnakangas
    <heikki.linnakangas@enterprisedb.com> wrote:
    > On 27.06.2012 18:55, Fujii Masao wrote:
    >>
    >> On Wed, Jun 27, 2012 at 11:56 PM, Heikki Linnakangas
    >> <heikki.linnakangas@enterprisedb.com>  wrote:
    >>>
    >>> On 27.06.2012 17:14, Amit Kapila wrote:
    >>>>
    >>>>
    >>>> 1. Function header for following functions still contains referece to
    >>>> log,
    >>>> seg
    >>>>    a. InstallXLogFileSegment()
    >>>>    b. RemoveOldXlogFiles()
    >>>>    c. XLogFileCopy()
    >>>>    d. XLogGetLastRemoved()
    >>>>    e. UpdateLastRemovedPtr()
    >>>>    f. RemoveOldXlogFiles()
    >>>
    >>>
    >>>
    >>> Thanks, fixed.
    >>
    >>
    >> There is still reference to log/seg in the comment of
    >> InstallXLogFileSegment().
    >> The attached patch should be applied?
    >
    >
    > Thanks, applied. Sorry for being so sloppy with this..
    
    No problem. WAL format change you did is really nice!
    
    Regards,
    
    -- 
    Fujii Masao
    
    
  7. Re: Regarding WAL Format Changes

    Amit Kapila <amit.kapila@huawei.com> — 2012-06-28T03:54:25Z

    From: Heikki Linnakangas [mailto:heikki.linnakangas@enterprisedb.com] 
    Sent: Wednesday, June 27, 2012 8:26 PM
    On 27.06.2012 17:14, Amit Kapila wrote:
    >> 2. @@ -2680,8 +2645,8 @@ InstallXLogFileSegment(uint32 *log, uint32 *seg,
    >> char *tmppath,
    >>                           LWLockRelease(ControlFileLock);
    >>                   ereport(LOG,
    >>                                   (errcode_for_file_access(),
    >> -                                 errmsg("could not link file \"%s\" to
    >> \"%s\" (initialization of log file %u, segment %u): %m",
    >> -                                                tmppath, path, *log,
    >> *seg)));
    >> +                                 errmsg("could not link file \"%s\" to
    >> \"%s\" (initialization of log file): %m",
    >> +                                                tmppath, path)));
    >>     If Changed error message can contain log file and segment number, it
    >>  would be more clear. That should be easily
    >>     deducible from segment number.
    
    >That seems redundant. The target file name is calculated from the 
    >segment number, and we're now using the file name instead of log+seg in 
    >other messages too.
    
    errmsg("could not link file \"%s\" to  \"%s\" (initialization of log file):
    %m", +                                                tmppath, path)));
    
    In this if we try to get the meaning of second part of message
    "(initialization of log file)", it was much 
    better previously as in this message it refers 2 files and previously it was
    clear initialization of which log
    file failed. So we can mention file name in second part of message
    "(initialization of log file)" as well.
    
    
    
    
    >> 3.   -RemoveOldXlogFiles(uint32 log, uint32 seg, XLogRecPtr endptr)
    >>    For the above 2 changed error messages, 'log segment' is used for
    >> filename.
    >>    However all similar changes has 'log file' for filename. There are
    some
    >> places
    >>    where 'log segment' is used and other places it is 'log file'.
    >>    So is there any particular reason for it?
    
    > Not really. There are several messages that use "log file %s", and also 
    > several places that use "log segment %s" Should we make it consistent 
    > and use either "log segment" or "log file" everywhere?
    
    'file' seems to be better option as some users may not be even aware of
    segments, they would be using default values of segments and they can relate
    to 'file' easily. 
    Also using 'WAL' instead of 'log' as suggested by Alvaro is good if others
    also thinks same.
    
    With Regards,
    Amit Kapila.