From 4cff100d7378b65ded116c5a9960584c351e5fa9 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 18 Feb 2011 13:11:45 -0500
Subject: [PATCH] Fix parallel pg_restore to handle comments on POST_DATA items
correctly.
The previous coding would try to process all SECTION_NONE items in the
initial sequential-restore pass, which failed if they were dependencies of
not-yet-restored items. Fix by postponing such items into the parallel
processing pass once we have skipped any non-PRE_DATA item.
Back-patch into 9.0; the original parallel-restore coding in 8.4 did not
have this bug, so no need to change it.
Report and diagnosis by Arnd Hannemann.
---
src/bin/pg_dump/pg_backup_archiver.c | 65 +++++++++++++++++++++-------
1 file changed, 50 insertions(+), 15 deletions(-)
diff --git a/src/bin/pg_dump/pg_backup_archiver.c b/src/bin/pg_dump/pg_backup_archiver.c
index 480264e911c..ff722db3c67 100644
--- a/src/bin/pg_dump/pg_backup_archiver.c
+++ b/src/bin/pg_dump/pg_backup_archiver.c
@@ -3218,12 +3218,12 @@ dumpTimestamp(ArchiveHandle *AH, const char *msg, time_t tim)
* Main engine for parallel restore.
*
* Work is done in three phases.
- * First we process tocEntries until we come to one that is marked
- * SECTION_DATA or SECTION_POST_DATA, in a single connection, just as for a
- * standard restore. Second we process the remaining non-ACL steps in
- * parallel worker children (threads on Windows, processes on Unix), each of
- * which connects separately to the database. Finally we process all the ACL
- * entries in a single connection (that happens back in RestoreArchive).
+ * First we process all SECTION_PRE_DATA tocEntries, in a single connection,
+ * just as for a standard restore. Second we process the remaining non-ACL
+ * steps in parallel worker children (threads on Windows, processes on Unix),
+ * each of which connects separately to the database. Finally we process all
+ * the ACL entries in a single connection (that happens back in
+ * RestoreArchive).
*/
static void
restore_toc_entries_parallel(ArchiveHandle *AH)
@@ -3233,6 +3233,7 @@ restore_toc_entries_parallel(ArchiveHandle *AH)
ParallelSlot *slots;
int work_status;
int next_slot;
+ bool skipped_some;
TocEntry pending_list;
TocEntry ready_list;
TocEntry *next_work_item;
@@ -3262,12 +3263,31 @@ restore_toc_entries_parallel(ArchiveHandle *AH)
* showing all the dependencies of SECTION_PRE_DATA items, so we do not
* risk trying to process them out-of-order.
*/
+ skipped_some = false;
for (next_work_item = AH->toc->next; next_work_item != AH->toc; next_work_item = next_work_item->next)
{
- /* Non-PRE_DATA items are just ignored for now */
- if (next_work_item->section == SECTION_DATA ||
- next_work_item->section == SECTION_POST_DATA)
- continue;
+ /* NB: process-or-continue logic must be the inverse of loop below */
+ if (next_work_item->section != SECTION_PRE_DATA)
+ {
+ /* DATA and POST_DATA items are just ignored for now */
+ if (next_work_item->section == SECTION_DATA ||
+ next_work_item->section == SECTION_POST_DATA)
+ {
+ skipped_some = true;
+ continue;
+ }
+ else
+ {
+ /*
+ * SECTION_NONE items, such as comments, can be processed now
+ * if we are still in the PRE_DATA part of the archive. Once
+ * we've skipped any items, we have to consider whether the
+ * comment's dependencies are satisfied, so skip it for now.
+ */
+ if (skipped_some)
+ continue;
+ }
+ }
ahlog(AH, 1, "processing item %d %s %s\n",
next_work_item->dumpId,
@@ -3310,17 +3330,32 @@ restore_toc_entries_parallel(ArchiveHandle *AH)
*/
par_list_header_init(&pending_list);
par_list_header_init(&ready_list);
+ skipped_some = false;
for (next_work_item = AH->toc->next; next_work_item != AH->toc; next_work_item = next_work_item->next)
{
- /* All PRE_DATA items were dealt with above */
+ /* NB: process-or-continue logic must be the inverse of loop above */
+ if (next_work_item->section == SECTION_PRE_DATA)
+ {
+ /* All PRE_DATA items were dealt with above */
+ continue;
+ }
if (next_work_item->section == SECTION_DATA ||
next_work_item->section == SECTION_POST_DATA)
{
- if (next_work_item->depCount > 0)
- par_list_append(&pending_list, next_work_item);
- else
- par_list_append(&ready_list, next_work_item);
+ /* set this flag at same point that previous loop did */
+ skipped_some = true;
}
+ else
+ {
+ /* SECTION_NONE items must be processed if previous loop didn't */
+ if (!skipped_some)
+ continue;
+ }
+
+ if (next_work_item->depCount > 0)
+ par_list_append(&pending_list, next_work_item);
+ else
+ par_list_append(&ready_list, next_work_item);
}
/*
--
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