On 5 September 2016 at 06:55, Michael Paquier <michael.paqu...@gmail.com> wrote: > On Sun, Sep 4, 2016 at 11:30 PM, Simon Riggs <si...@2ndquadrant.com> wrote:
>> I noticed we don't mention what LSN is anywhere, so I'd like to apply >> the following doc patch also. > > +1 for the idea. What do you think about adding a mention to the > system data type pg_lsn? > > <para> > + <acronym>WAL</acronym> records are appended to the <acronym>WAL</acronym> > + logs as each new record is written. The insert position is described by > + a Log Sequence Number (<acronym>LSN</acronym>) that is a byte offset into > + the logs, increasing monotonically with each new record. Two > + <acronym>LSN</acronym>s can be compared to calculate the volume of > + <acronym>WAL</acronym> data that separates them, so are used to measure > + progress of <acronym>WAL</acronym> during replication and recovery. > + </para> > Here we could for example append a sentence like "The system data type > <link linkend="datatype-pg-lsn"><type>pg_lsn</></link> is an internal > representation of the LSN". Good input, thanks. v2 attached. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
doc_lsn.v2.patch
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