Re: [BUGS] BUG #8257: Multi-Core Restore fails when containing index comments
Hi Lloyd,
On 2013-06-26 23:43:00 +, lal...@fhcrc.org wrote:
I have found the restore will fail when using pg_restore's -j option, with
more than one core, on a dump that contains a COMMENT INDEX.
Run this next section to add the table, index, and index comment to the
test_db database.
CREATE TABLE public.tbl_test (
pkey TEXT NOT NULL,
CONSTRAINT tbl_test_pkey PRIMARY KEY(pkey)
);
COMMENT ON INDEX public.tbl_test_pkey
IS 'Index Comment';
Once this test database is created, create a backup of the database.
pg_dump -Fc test_db test_db.dump
The problem is that pg_dump makes the comment depend on the index
instead of the constraint:
; Selected TOC Entries:
...
170; 1259 69261 TABLE public tbl_test andres
;depends on: 6
1941; 0 69261 TABLE DATA public tbl_test andres
; depends on: 170
1833; 2606 69268 CONSTRAINT public tbl_test_pkey andres
; depends on: 170 170
1950; 0 0 COMMENT public INDEX tbl_test_pkey andres
; depends on: 1832
There is no object 1832 in the dump since that was ommitted in favor of
the constraint 1833 which internally creates the index. So what we need
to do is to make the comment depend on the constraint instead.
With the attached patch we get:
170; 1259 69261 TABLE public tbl_test andres
;depends on: 6
1941; 0 69261 TABLE DATA public tbl_test andres
; depends on: 170
1833; 2606 69268 CONSTRAINT public tbl_test_pkey andres
; depends on: 170 170
1950; 0 0 COMMENT public INDEX tbl_test_pkey andres
; depends on: 1833
unsurprisingly after that restore completes.
Greetings,
Andres Freund
--
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training Services
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 2ce0cd8..107cabb 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -13493,6 +13493,7 @@ dumpIndex(Archive *fout, IndxInfo *indxinfo)
PQExpBuffer q;
PQExpBuffer delq;
PQExpBuffer labelq;
+ bool is_constraint = indxinfo-indexconstraint != 0;
if (dataOnly)
return;
@@ -13509,7 +13510,7 @@ dumpIndex(Archive *fout, IndxInfo *indxinfo)
* do dump any comment for it. (This is safe because dependency ordering
* will have ensured the constraint is emitted first.)
*/
- if (indxinfo-indexconstraint == 0)
+ if (!is_constraint)
{
if (binary_upgrade)
binary_upgrade_set_pg_class_oids(fout, q,
@@ -13547,11 +13548,15 @@ dumpIndex(Archive *fout, IndxInfo *indxinfo)
NULL, NULL);
}
- /* Dump Index Comments */
+ /*
+ * Dump Index Comments - depend on the constraint instead of the index if
+ * present to ensure sensible ordering.
+ */
dumpComment(fout, labelq-data,
tbinfo-dobj.namespace-dobj.name,
tbinfo-rolname,
-indxinfo-dobj.catId, 0, indxinfo-dobj.dumpId);
+indxinfo-dobj.catId, 0,
+ is_constraint ? indxinfo-indexconstraint : indxinfo-dobj.dumpId);
destroyPQExpBuffer(q);
destroyPQExpBuffer(delq);
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Re: [BUGS] BUG #8257: Multi-Core Restore fails when containing index comments
Andres Freund and...@2ndquadrant.com writes: The problem is that pg_dump makes the comment depend on the index instead of the constraint: Yeah, I figured that out yesterday, but hadn't gotten to writing a patch yet. ... So what we need to do is to make the comment depend on the constraint instead. Your proposed patch will only fix the problem for dumps created after it ships. In the past, we've tried to deal with this type of issue by having pg_restore fix up the dependencies when reading a dump, so that it would still work on existing dumps. I'm afraid there may be no way to do that in this case --- it doesn't look like there's enough info in the dump to tell where the dependency link should have led. But we should think about it a little before taking the easy way out. regards, tom lane -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
Re: [BUGS] BUG #8257: Multi-Core Restore fails when containing index comments
On 2013-06-27 10:29:14 -0400, Tom Lane wrote: ... So what we need to do is to make the comment depend on the constraint instead. Your proposed patch will only fix the problem for dumps created after it ships. In the past, we've tried to deal with this type of issue by having pg_restore fix up the dependencies when reading a dump, so that it would still work on existing dumps. Yes :(. On the other hand, it's probably not too common to create comments on indexes that haven't been created explicitly. I'm afraid there may be no way to do that in this case --- it doesn't look like there's enough info in the dump to tell where the dependency link should have led. But we should think about it a little before taking the easy way out. The only thing I could think of - but which I thought to be too kludgey - was to simply delay the creation of all comments and restore them together with ACLs. I don't think we can have dependencies towards comments. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training Services -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
Re: [BUGS] BUG #8257: Multi-Core Restore fails when containing index comments
Andres Freund and...@2ndquadrant.com writes: On 2013-06-27 10:29:14 -0400, Tom Lane wrote: Your proposed patch will only fix the problem for dumps created after it ships. In the past, we've tried to deal with this type of issue by having pg_restore fix up the dependencies when reading a dump, so that it would still work on existing dumps. Yes :(. On the other hand, it's probably not too common to create comments on indexes that haven't been created explicitly. Perhaps. The lack of previous complaints does suggest this situation isn't so common. I'm afraid there may be no way to do that in this case --- it doesn't look like there's enough info in the dump to tell where the dependency link should have led. But we should think about it a little before taking the easy way out. The only thing I could think of - but which I thought to be too kludgey - was to simply delay the creation of all comments and restore them together with ACLs. I don't like that either, though we may be forced into it if we find more bugs in comment dependencies. Anyway, fixing pg_dump's logic is not wrong; I was just hoping we could also think of a workaround on the pg_restore side. regards, tom lane -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
Re: [BUGS] BUG #8257: Multi-Core Restore fails when containing index comments
Andres Freund and...@2ndquadrant.com writes: There is no object 1832 in the dump since that was ommitted in favor of the constraint 1833 which internally creates the index. So what we need to do is to make the comment depend on the constraint instead. With the attached patch we get: [ the right thing ] Applied with minor cosmetic changes. regards, tom lane -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
[BUGS] BUG #8257: Multi-Core Restore fails when containing index comments
The following bug has been logged on the website: Bug reference: 8257 Logged by: Lloyd Albin Email address: lal...@fhcrc.org PostgreSQL version: 9.2.4 Operating system: SUSE Linux (64-bit) Description: I have found the restore will fail when using pg_restore's -j option, with more than one core, on a dump that contains a COMMENT INDEX. I have tried this using both Postgres 9.0.12 9.2.4 I have created a test case that shows the problem. Create a database called test_db. CREATE DATABASE test_db WITH OWNER = postgres ENCODING = 'UTF8' TEMPLATE = template0; Run this next section to add the table, index, and index comment to the test_db database. CREATE TABLE public.tbl_test ( pkey TEXT NOT NULL, CONSTRAINT tbl_test_pkey PRIMARY KEY(pkey) ); COMMENT ON INDEX public.tbl_test_pkey IS 'Index Comment'; Once this test database is created, create a backup of the database. pg_dump -Fc test_db test_db.dump Drop the test database and now lets restore it. pg_restore -C -j 3 -d postgres -Fc test_db.dump pg_restore: [archiver (db)] Error while PROCESSING TOC: pg_restore: [archiver (db)] Error from TOC entry 2525; 0 0 COMMENT INDEX tbl_test_pkey postgres pg_restore: [archiver (db)] could not execute query: ERROR: relation tbl_test_pkey does not exist Command was: COMMENT ON INDEX tbl_test_pkey IS 'Index Comment'; pg_restore: [archiver] worker process failed: exit code 1 If you use -j 1 or skip the -j option the restore will restore without any errors. Lloyd Albin Statistical Center for HIV/AIDS Research and Prevention (SCHARP) Vaccine and Infectious Disease Division (VIDD) Fred Hutchinson Cancer Research Center (FHCRC) -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
