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Clean up some minor inefficiencies in parallel dump/restore.

Parallel dump did a totally pointless query to find out the name of each
table to be dumped, which it already knows.  Parallel restore runs issued
lots of redundant SET commands because _doSetFixedOutputState() was invoked
once per TOC item rather than just once at connection start.  While the
extra queries are insignificant if you're dumping or restoring large
tables, it still seems worth getting rid of them.

Also, give the responsibility for selecting the right client_encoding for
a parallel dump worker to setup_connection() where it naturally belongs,
instead of having ad-hoc code for that in CloneArchive().  And fix some
minor bugs like use of strdup() where pg_strdup() would be safer.

Back-patch to 9.3, mostly to keep the branches in sync in an area that
we're still finding bugs in.

Discussion: <5086.1464793073@sss.pgh.pa.us>
This commit is contained in:
Tom Lane
2016-06-01 16:14:21 -04:00
parent 47215c16f2
commit 43d3fbe369
3 changed files with 34 additions and 50 deletions

View File

@@ -3831,6 +3831,7 @@ restore_toc_entries_postfork(ArchiveHandle *AH, TocEntry *pending_list)
ropt->pghost, ropt->pgport, ropt->username,
ropt->promptPassword);
/* re-establish fixed state */
_doSetFixedOutputState(AH);
/*
@@ -4009,10 +4010,9 @@ parallel_restore(ParallelArgs *args)
TocEntry *te = args->te;
int status;
_doSetFixedOutputState(AH);
Assert(AH->connection != NULL);
/* Count only errors associated with this TOC entry */
AH->public.n_errors = 0;
/* Restore the TOC item */
@@ -4381,10 +4381,14 @@ CloneArchive(ArchiveHandle *AH)
RestoreOptions *ropt = AH->public.ropt;
Assert(AH->connection == NULL);
/* this also sets clone->connection */
ConnectDatabase((Archive *) clone, ropt->dbname,
ropt->pghost, ropt->pgport, ropt->username,
ropt->promptPassword);
/* re-establish fixed state */
_doSetFixedOutputState(clone);
}
else
{
@@ -4392,7 +4396,6 @@ CloneArchive(ArchiveHandle *AH)
char *pghost;
char *pgport;
char *username;
const char *encname;
Assert(AH->connection != NULL);
@@ -4406,18 +4409,11 @@ CloneArchive(ArchiveHandle *AH)
pghost = PQhost(AH->connection);
pgport = PQport(AH->connection);
username = PQuser(AH->connection);
encname = pg_encoding_to_char(AH->public.encoding);
/* this also sets clone->connection */
ConnectDatabase((Archive *) clone, dbname, pghost, pgport, username, TRI_NO);
/*
* Set the same encoding, whatever we set here is what we got from
* pg_encoding_to_char(), so we really shouldn't run into an error
* setting that very same value. Also see the comment in
* SetupConnection().
*/
PQsetClientEncoding(clone->connection, encname);
/* setupDumpWorker will fix up connection state */
}
/* Let the format-specific code have a chance too */