Florian Pflug wrote:
> On Jul11, 2011, at 17:31 , Bruce Momjian wrote:
> > Tom Lane wrote:
> >> Florian Pflug <[email protected]> writes:
> >>> On Jul11, 2011, at 17:11 , Tom Lane wrote:
> >>>> Yeah, I think this patch is going in the wrong direction altogether.
> >>>> It would be better to modify the description of virtualtransaction
> >>>> and pid to say that those are the "locking" entity.
> >>
> >>> Hm, we already kinda of say that. Both descriptions include the phrase
> >>> "... holding or awaiting this lock.". The column "mode" says
> >>> "... held or desired by this process", which I guess is similar enough
> >>> to make it clear that these are related.
> >>
> >>> Its the columns which refer to the locked object which simply say
> >>> "object", and thus leave it open if that means locked or a locking.
> >>
> >>> Could we split that table in two parts, one for the fields referring
> >>> to the locked object and one for the locking entity, or does that depart
> >>> too far from the way we document other system catalogs and views?
> >>
> >> Then you'd have to join them, which would not be an improvement from
> >> anybody's standpoint.
> >>
> >> Maybe we could just add a paragraph above the "pg_locks Columns" table
> >> that says explicitly that virtualtransaction and pid describe the entity
> >> holding or awaiting the lock, and the others describe the object being
> >> locked? Any way you slice it, putting this information into the
> >> per-column table is going to be repetitive.
> >
> > Frankly, whenever anyone says "object", they might as well call it
> > "thing". It seems to be a content-less word. Maybe just replace the
> > word "object" with "lock".
>
> I like that, as long as we make it ".. lock is/isn't *on* a ...", and not
> just "... lock is/isn't a". After all, the lock very clearly isn't a
> relation or xid or whatever - it's a, well, lock.
>
> We'd then have
> OID of the database in which the lock exists, or zero if the lock is on a
> shared object, or null if the lock is on a transaction ID.
>
> OID of the relation, or null if the lock is not on a relation or part of a
> relation.
>
> ...
>
> ID of a transaction, or null if the lock is not on a transaction ID
OK, I went with this wording, using "lock object is on" terminology.
Applied patch attached --- adjustments welcomed.
--
Bruce Momjian <[email protected]> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ It's impossible for everything to be true. +
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
new file mode 100644
index d4a1d36..c5851af
*** a/doc/src/sgml/catalogs.sgml
--- b/doc/src/sgml/catalogs.sgml
***************
*** 6930,6936 ****
<entry>
OID of the database in which the object exists, or
zero if the object is a shared object, or
! null if the object is a transaction ID
</entry>
</row>
<row>
--- 6930,6936 ----
<entry>
OID of the database in which the object exists, or
zero if the object is a shared object, or
! null if the lock object is on a transaction ID
</entry>
</row>
<row>
***************
*** 6938,6945 ****
<entry><type>oid</type></entry>
<entry><literal><link linkend="catalog-pg-class"><structname>pg_class</structname></link>.oid</literal></entry>
<entry>
! OID of the relation, or null if the object is not
! a relation or part of a relation
</entry>
</row>
<row>
--- 6938,6945 ----
<entry><type>oid</type></entry>
<entry><literal><link linkend="catalog-pg-class"><structname>pg_class</structname></link>.oid</literal></entry>
<entry>
! OID of the relation, or null if the lock object is not
! on a relation or part of a relation
</entry>
</row>
<row>
***************
*** 6947,6954 ****
<entry><type>integer</type></entry>
<entry></entry>
<entry>
! Page number within the relation, or null if the object
! is not a tuple or relation page
</entry>
</row>
<row>
--- 6947,6954 ----
<entry><type>integer</type></entry>
<entry></entry>
<entry>
! Page number within the relation, or null if the lock object
! is not on a tuple or relation page
</entry>
</row>
<row>
***************
*** 6956,6962 ****
<entry><type>smallint</type></entry>
<entry></entry>
<entry>
! Tuple number within the page, or null if the object is not a tuple
</entry>
</row>
<row>
--- 6956,6963 ----
<entry><type>smallint</type></entry>
<entry></entry>
<entry>
! Tuple number within the page, or null if the lock object is not
! on a tuple
</entry>
</row>
<row>
***************
*** 6964,6971 ****
<entry><type>text</type></entry>
<entry></entry>
<entry>
! Virtual ID of a transaction, or null if the object is not a
! virtual transaction ID
</entry>
</row>
<row>
--- 6965,6972 ----
<entry><type>text</type></entry>
<entry></entry>
<entry>
! Virtual ID of a transaction lock, or null if the lock object is not
! on a virtual transaction ID
</entry>
</row>
<row>
***************
*** 6973,6979 ****
<entry><type>xid</type></entry>
<entry></entry>
<entry>
! ID of a transaction, or null if the object is not a transaction ID
</entry>
</row>
<row>
--- 6974,6980 ----
<entry><type>xid</type></entry>
<entry></entry>
<entry>
! ID of a transaction lock, or null if the lock object is not on a transaction ID
</entry>
</row>
<row>
***************
*** 6982,6988 ****
<entry><literal><link linkend="catalog-pg-class"><structname>pg_class</structname></link>.oid</literal></entry>
<entry>
OID of the system catalog containing the object, or null if the
! object is not a general database object
</entry>
</row>
<row>
--- 6983,6989 ----
<entry><literal><link linkend="catalog-pg-class"><structname>pg_class</structname></link>.oid</literal></entry>
<entry>
OID of the system catalog containing the object, or null if the
! lock object is not on a general database object.
</entry>
</row>
<row>
***************
*** 6991,6997 ****
<entry>any OID column</entry>
<entry>
OID of the object within its system catalog, or null if the
! object is not a general database object.
For advisory locks it is used to distinguish the two key
spaces (1 for an int8 key, 2 for two int4 keys).
</entry>
--- 6992,6998 ----
<entry>any OID column</entry>
<entry>
OID of the object within its system catalog, or null if the
! lock object is not on a general database object.
For advisory locks it is used to distinguish the two key
spaces (1 for an int8 key, 2 for two int4 keys).
</entry>
***************
*** 7004,7010 ****
For a table column, this is the column number (the
<structfield>classid</> and <structfield>objid</> refer to the
table itself). For all other object types, this column is
! zero. Null if the object is not a general database object
</entry>
</row>
<row>
--- 7005,7011 ----
For a table column, this is the column number (the
<structfield>classid</> and <structfield>objid</> refer to the
table itself). For all other object types, this column is
! zero. Null if the lock object is not on a general database object.
</entry>
</row>
<row>
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