Possible mistake in Section 63.6 - 9.6devel Documentation
Hello,
It has been mentioned in Section 63.6 that the first two fields in
PageHeaderData track the most recent WAL entry related to the page.
However, I am not sure how pd_checksum is related to WAL. Could it be
possible that the sentence has been carried over from previous versions of
the documentations without considering the change to the second field in
PageHeaderData?
Thanks,
Vignesh.
On Tue, Jul 21, 2015 at 6:54 AM, Vignesh Raghunathan
<vignesh.pgsql@gmail.com> wrote:
Hello,
It has been mentioned in Section 63.6 that the first two fields in
PageHeaderData track the most recent WAL entry related to the page. However,
I am not sure how pd_checksum is related to WAL. Could it be possible that
the sentence has been carried over from previous versions of the
documentations without considering the change to the second field in
PageHeaderData?
Yes, the documentation is mistaken. The two bytes of pd_tli have been
switched to pd_checksum in 9.3, hence only the first field is relevant
for WAL, aka pd_lsn. Looking at this portion of the docs I think that
it should be updated as attached, mentioning pd_checksum as well.
--
Michael
Attachments:
20150721_pageheader_docfix.patchtext/x-patch; charset=US-ASCII; name=20150721_pageheader_docfix.patchDownload+12-12
On Tue, Jul 21, 2015 at 9:59 AM, Michael Paquier
<michael.paquier@gmail.com> wrote:
On Tue, Jul 21, 2015 at 6:54 AM, Vignesh Raghunathan
<vignesh.pgsql@gmail.com> wrote:Hello,
It has been mentioned in Section 63.6 that the first two fields in
PageHeaderData track the most recent WAL entry related to the page. However,
I am not sure how pd_checksum is related to WAL. Could it be possible that
the sentence has been carried over from previous versions of the
documentations without considering the change to the second field in
PageHeaderData?Yes, the documentation is mistaken. The two bytes of pd_tli have been
switched to pd_checksum in 9.3, hence only the first field is relevant
for WAL, aka pd_lsn. Looking at this portion of the docs I think that
it should be updated as attached, mentioning pd_checksum as well.
Also the type of pd_lsn in the Table 63-3 should be PageXLogRecPtr.
Regards,
--
Fujii Masao
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On Thu, Sep 10, 2015 at 12:42 AM, Fujii Masao <masao.fujii@gmail.com> wrote:
On Tue, Jul 21, 2015 at 9:59 AM, Michael Paquier
<michael.paquier@gmail.com> wrote:On Tue, Jul 21, 2015 at 6:54 AM, Vignesh Raghunathan
<vignesh.pgsql@gmail.com> wrote:Hello,
It has been mentioned in Section 63.6 that the first two fields in
PageHeaderData track the most recent WAL entry related to the page. However,
I am not sure how pd_checksum is related to WAL. Could it be possible that
the sentence has been carried over from previous versions of the
documentations without considering the change to the second field in
PageHeaderData?Yes, the documentation is mistaken. The two bytes of pd_tli have been
switched to pd_checksum in 9.3, hence only the first field is relevant
for WAL, aka pd_lsn. Looking at this portion of the docs I think that
it should be updated as attached, mentioning pd_checksum as well.Also the type of pd_lsn in the Table 63-3 should be PageXLogRecPtr.
Yep. See attached FWIW.
--
Michael
Attachments:
20150910_pageheader_docfix_v2.patchtext/x-diff; charset=US-ASCII; name=20150910_pageheader_docfix_v2.patchDownload+13-13
On Thu, Sep 10, 2015 at 3:05 PM, Michael Paquier
<michael.paquier@gmail.com> wrote:
On Thu, Sep 10, 2015 at 12:42 AM, Fujii Masao <masao.fujii@gmail.com> wrote:
On Tue, Jul 21, 2015 at 9:59 AM, Michael Paquier
<michael.paquier@gmail.com> wrote:On Tue, Jul 21, 2015 at 6:54 AM, Vignesh Raghunathan
<vignesh.pgsql@gmail.com> wrote:Hello,
It has been mentioned in Section 63.6 that the first two fields in
PageHeaderData track the most recent WAL entry related to the page. However,
I am not sure how pd_checksum is related to WAL. Could it be possible that
the sentence has been carried over from previous versions of the
documentations without considering the change to the second field in
PageHeaderData?Yes, the documentation is mistaken. The two bytes of pd_tli have been
switched to pd_checksum in 9.3, hence only the first field is relevant
for WAL, aka pd_lsn. Looking at this portion of the docs I think that
it should be updated as attached, mentioning pd_checksum as well.Also the type of pd_lsn in the Table 63-3 should be PageXLogRecPtr.
Yep. See attached FWIW.
Thanks! Applied.
Regards,
--
Fujii Masao
--
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