Looks reasonable to me. All the patch does is make sure that the result
set is valid. Probably a check I should have done from the beginning,
or pg _autovacuum should be locking tables to make sure they aren't
dropped, but that sounds too intrusive, this is probably better.
Matt
daveg wrote:
Apologies if this is old news, but pg_autovacuum in 8.0.x has the bad habit
of SEGVing and exiting when a table gets dropped out from under it. This
creates problems if you rely on pg_autovacuum for the bulk of your vacuuming
as it forgets it's statistics when it is restarted and so will skip some
desireable vacuums.
I looked at the new autovacuum in 8.1 and it appears from casual inspection
not to have the same problem.
Below is a patch for this that should apply against any 8.0.x. The change
verifies that the catalog query returned some rows before accessing the row
data.
-dg
diff -Naur source/postgresql-8.0.2/contrib/pg_autovacuum/pg_autovacuum.c
build/postgresql-8.0.2/contrib/pg_autovacuum/pg_autovacuum.c
--- source/postgresql-8.0.2/contrib/pg_autovacuum/pg_autovacuum.c
2005-04-02 16:02:03.000000000 -0800
+++ build/postgresql-8.0.2/contrib/pg_autovacuum/pg_autovacuum.c
2005-09-28 22:15:25.428710172 -0700
@@ -1013,6 +1013,7 @@
static void
perform_maintenance_command(db_info * dbi, tbl_info * tbl, int operation)
{
+ PGresult *res;
char buf[256];
/*
@@ -1069,10 +1070,16 @@
fflush(LOGOUTPUT);
}
- send_query(buf, dbi);
-
- update_table_thresholds(dbi, tbl, operation);
-
+ res = send_query(buf, dbi);
+ if (PQntuples(res)) {
+ update_table_thresholds(dbi, tbl, operation);
+ } else {
+ if (args->debug >= 1) {
+ sprintf(logbuffer, "Cannot refind table %s",
tbl->table_name);
+ log_entry(logbuffer, LVL_DEBUG);
+ fflush(LOGOUTPUT);
+ }
+ }
if (args->debug >= 2)
print_table_info(tbl);
}
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