On Wed, Sep 16, 2020 at 10:40 AM Ashutosh Sharma <ashu.coe...@gmail.com> wrote:
>
> On Wed, Sep 16, 2020 at 9:14 AM Tom Lane <t...@sss.pgh.pa.us> wrote:
> >
> > Ashutosh Sharma <ashu.coe...@gmail.com> writes:
> > > On Wed, Sep 16, 2020 at 1:25 AM Tom Lane <t...@sss.pgh.pa.us> wrote:
> > >> * Should any of the other tables in the test be converted to temp?
> >
> > > Are you trying to say that we can achieve the things being done in
> > > test-case 1 and 2 by having a single temp table and we should aim for
> > > it because it will make the test-case more efficient and easy to
> > > maintain?
> >
> > Well, I'm just looking at the comment that says the reason for the
> > begin/rollback structure is to keep autovacuum's hands off the table.
> > In most if not all of the other places where we need that, the preferred
> > method is to make the table temp or mark it with (autovacuum = off).
> > While this way isn't wrong exactly, nor inefficient, it does seem
> > a little restrictive. For instance, you can't easily test cases that
> > involve intentional errors.
> >
> > Another point is that we have a few optimizations that apply to tables
> > created in the current transaction. I'm not sure whether any of them
> > would fire in this test case, but if they do (now or in the future)
> > that might mean you aren't testing the usual scenario for use of
> > pg_surgery, which is surely not going to be a new-in-transaction
> > table. (That might be an argument for preferring autovacuum = off
> > over a temp table, too.)
> >
>
> I agree with you on both the above points. I'll try to make the
> necessary changes to address all your comments. Also, I'd prefer
> creating a normal heap table with autovacuum = off over the temp table
> for the reasons you mentioned in the second point.
>
Attached is the patch with the changes suggested here. I've tried to
use a normal heap table with (autovacuum = off) wherever possible.
Please have a look and let me know for any other issues.
Thanks,
--
With Regards,
Ashutosh Sharma
EnterpriseDB:http://www.enterprisedb.com
diff --git a/contrib/pg_surgery/expected/heap_surgery.out b/contrib/pg_surgery/expected/heap_surgery.out
index 9451c57..033e3aa 100644
--- a/contrib/pg_surgery/expected/heap_surgery.out
+++ b/contrib/pg_surgery/expected/heap_surgery.out
@@ -1,8 +1,8 @@
create extension pg_surgery;
-- create a normal heap table and insert some rows.
--- note that we don't commit the transaction, so autovacuum can't interfere.
-begin;
-create table htab(a int);
+-- note that we don't want autovacuum to interfere and therefore we disable it
+-- on the test table.
+create table htab(a int) with (autovacuum_enabled = off);
insert into htab values (100), (200), (300), (400), (500);
-- test empty TID array
select heap_force_freeze('htab'::regclass, ARRAY[]::tid[]);
@@ -85,9 +85,10 @@ NOTICE: skipping tid (0, 6) for relation "htab" because the item number is out
(1 row)
-rollback;
-- set up a new table with a redirected line pointer
-create table htab2(a int) with (autovacuum_enabled = off);
+-- note that unlike other test cases we need a temp table here to ensure that we
+-- get a stable vacuum results.
+create temp table htab2(a int);
insert into htab2 values (100);
update htab2 set a = 200;
vacuum htab2;
@@ -175,6 +176,6 @@ ERROR: "vw" is not a table, materialized view, or TOAST table
select heap_force_freeze('vw'::regclass, ARRAY['(0, 1)']::tid[]);
ERROR: "vw" is not a table, materialized view, or TOAST table
-- cleanup.
-drop table htab2;
+drop table htab;
drop view vw;
drop extension pg_surgery;
diff --git a/contrib/pg_surgery/sql/heap_surgery.sql b/contrib/pg_surgery/sql/heap_surgery.sql
index 8a27214..234e667 100644
--- a/contrib/pg_surgery/sql/heap_surgery.sql
+++ b/contrib/pg_surgery/sql/heap_surgery.sql
@@ -1,9 +1,9 @@
create extension pg_surgery;
-- create a normal heap table and insert some rows.
--- note that we don't commit the transaction, so autovacuum can't interfere.
-begin;
-create table htab(a int);
+-- note that we don't want autovacuum to interfere and therefore we disable it
+-- on the test table.
+create table htab(a int) with (autovacuum_enabled = off);
insert into htab values (100), (200), (300), (400), (500);
-- test empty TID array
@@ -38,10 +38,10 @@ select ctid, xmax from htab where xmin = 2;
-- out-of-range TIDs should be skipped
select heap_force_freeze('htab'::regclass, ARRAY['(0, 0)', '(0, 6)']::tid[]);
-rollback;
-
-- set up a new table with a redirected line pointer
-create table htab2(a int) with (autovacuum_enabled = off);
+-- note that unlike other test cases we need a temp table here to ensure that we
+-- get a stable vacuum results.
+create temp table htab2(a int);
insert into htab2 values (100);
update htab2 set a = 200;
vacuum htab2;
@@ -86,6 +86,6 @@ select heap_force_kill('vw'::regclass, ARRAY['(0, 1)']::tid[]);
select heap_force_freeze('vw'::regclass, ARRAY['(0, 1)']::tid[]);
-- cleanup.
-drop table htab2;
+drop table htab;
drop view vw;
drop extension pg_surgery;
