Joshua Drake wrote:
On Fri, 26 Sep 2008 17:10:44 -0400
Andrew Dunstan <[EMAIL PROTECTED]> wrote:
Yes, there are several funny things going on, including some stuff
with dependencies. I'll have a new patch tomorrow with luck. Thanks
for testing.
O.k. I took at look at the patch itself and although I don't understand
all of it there were a couple of red flags to me:
+ if (ropt->create)
+ die_horribly(AH,modulename,
+ "parallel restore is
incompatible with --create\n");
+
This seems like an odd limitation. In my mind, the schema would not be
restored in parallel. The schema before data would restore as a single
thread. Even the largest schemas would only take minutes (if that).
Thus something like --create should never be a problem.
Originally I had everything restoring in parallel. Now I am in fact (as
the patch should have showed you) restoring the first part in a single
thread like you say. Thus I probably can relax that restriction. I will
look and see.
I also noticed you check if we have zlib? Is it even possible to use
the c format without it? (that would be new to me).
I noticed this line:
+ while((next_work_item = get_next_work_item(AH)) != NULL)
+ {
+ /* XXX need to improve this test in case there is no
table data */
+ /* need to test for indexes, FKs, PK, Unique, etc */
+ if(strcmp(next_work_item->desc,"TABLE DATA") == 0)
+ break;
+ (void) _restore_one_te(AH, next_work_item, ropt,
false);
+
+ next_work_item->prestored = true;
+
+ _reduce_dependencies(AH,next_work_item);
+ }
Intead of the TABLE DATA compare, perhaps it makes sense to back patch
pg_dump to have a line delimiter in the TOC? That way even if there is
no TABLE DATA there would be a delimiter that says:
--- BEGIN TABLE DATA
--- END TABLE DATA
Thus if nothing is there... nothing is there?
The TOC isn't stored as a text file. So we'll need to look by entry
tags. It's no big deal - there aren't a huge number.
+ /* delay just long enough betweek forks to
give the catalog some
+ * breathing space. Without this sleep I got
+ * "tuple concurrently updated" errors.
+ */
+ pg_usleep(500000);
+ continue; /* in case the slots are not yet
full */
+ }
Could that be solved with a lock instead? Once the lock is released....
That sleep is now gone.
Anyway... just some thoughts. I apologize if I misunderstood the patch.
No problem. Thanks for looking.
cheers
andrew
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