Actually, all of parallel restore's limitations should be tested earlier.

On closer inspection, whining in restore_toc_entries_parallel is really
much too late for any user-facing error case.  The right place to do it
is at the start of RestoreArchive(), before we've done anything interesting
(suh as trying to DROP all the targets ...)

Back-patch to 8.4, where parallel restore was introduced.

diff --git a/src/bin/pg_dump/pg_backup_archiver.c b/src/bin/pg_dump/pg_backup_archiver.c
index d4b414fbcfe6f545c6fb3390ed827fb906c5d4a7..791251313ada34d6691642c37c3ee8ba11afe24c 100644 (file)
--- a/src/bin/pg_dump/pg_backup_archiver.c
+++ b/src/bin/pg_dump/pg_backup_archiver.c
@@ -204,6 +204,7 @@ void
 RestoreArchive(Archive *AHX, RestoreOptions *ropt)
 {
        ArchiveHandle *AH = (ArchiveHandle *) AHX;
+       bool            parallel_mode;
        TocEntry   *te;
        teReqs          reqs;
        OutputContext sav;
@@ -229,6 +230,27 @@ RestoreArchive(Archive *AHX, RestoreOptions *ropt)
        if (ropt->createDB && ropt->single_txn)
                die_horribly(AH, modulename, "-C and -1 are incompatible options\n");
 
+       /*
+        * If we're going to do parallel restore, there are some restrictions.
+        */
+       parallel_mode = (ropt->number_of_jobs > 1 && ropt->useDB);
+       if (parallel_mode)
+       {
+               /* We haven't got round to making this work for all archive formats */
+               if (AH->ClonePtr == NULL || AH->ReopenPtr == NULL)
+                       die_horribly(AH, modulename, "parallel restore is not supported with this archive file format\n");
+
+               /* Doesn't work if the archive represents dependencies as OIDs */
+               if (AH->version < K_VERS_1_8)
+                       die_horribly(AH, modulename, "parallel restore is not supported with archives made by pre-8.0 pg_dump\n");
+
+               /*
+                * It's also not gonna work if we can't reopen the input file, so
+                * let's try that immediately.
+                */
+               (AH->ReopenPtr) (AH);
+       }
+
        /*
         * Make sure we won't need (de)compression we haven't got
         */
@@ -375,7 +397,7 @@ RestoreArchive(Archive *AHX, RestoreOptions *ropt)
         *
         * In parallel mode, turn control over to the parallel-restore logic.
         */
-       if (ropt->number_of_jobs > 1 && ropt->useDB)
+       if (parallel_mode)
                restore_toc_entries_parallel(AH);
        else
        {
@@ -3192,20 +3214,6 @@ restore_toc_entries_parallel(ArchiveHandle *AH)
 
        ahlog(AH, 2, "entering restore_toc_entries_parallel\n");
 
-       /* we haven't got round to making this work for all archive formats */
-       if (AH->ClonePtr == NULL || AH->ReopenPtr == NULL)
-               die_horribly(AH, modulename, "parallel restore is not supported with this archive file format\n");
-
-       /* doesn't work if the archive represents dependencies as OIDs, either */
-       if (AH->version < K_VERS_1_8)
-               die_horribly(AH, modulename, "parallel restore is not supported with archives made by pre-8.0 pg_dump\n");
-
-       /*
-        * It's also not gonna work if we can't reopen the input file, so let's
-        * try that immediately.
-        */
-       (AH->ReopenPtr) (AH);
-
        slots = (ParallelSlot *) calloc(sizeof(ParallelSlot), n_slots);
 
        /* Adjust dependency information */