diff options
Diffstat (limited to 'src/bin/pg_upgrade/pg_upgrade.c')
| -rw-r--r-- | src/bin/pg_upgrade/pg_upgrade.c | 60 |
1 files changed, 52 insertions, 8 deletions
diff --git a/src/bin/pg_upgrade/pg_upgrade.c b/src/bin/pg_upgrade/pg_upgrade.c index 536e49d2616..d5cd5bf0b3a 100644 --- a/src/bin/pg_upgrade/pg_upgrade.c +++ b/src/bin/pg_upgrade/pg_upgrade.c @@ -67,6 +67,7 @@ static void set_frozenxids(bool minmxid_only); static void make_outputdirs(char *pgdata); static void setup(char *argv0); static void create_logical_replication_slots(void); +static void create_conflict_detection_slot(void); ClusterInfo old_cluster, new_cluster; @@ -88,6 +89,7 @@ int main(int argc, char **argv) { char *deletion_script_file_name = NULL; + bool migrate_logical_slots; /* * pg_upgrade doesn't currently use common/logging.c, but initialize it @@ -198,18 +200,39 @@ main(int argc, char **argv) new_cluster.pgdata); check_ok(); + migrate_logical_slots = count_old_cluster_logical_slots(); + /* - * Migrate the logical slots to the new cluster. Note that we need to do - * this after resetting WAL because otherwise the required WAL would be - * removed and slots would become unusable. There is a possibility that - * background processes might generate some WAL before we could create the - * slots in the new cluster but we can ignore that WAL as that won't be - * required downstream. + * Migrate replication slots to the new cluster. + * + * Note that we must migrate logical slots after resetting WAL because + * otherwise the required WAL would be removed and slots would become + * unusable. There is a possibility that background processes might + * generate some WAL before we could create the slots in the new cluster + * but we can ignore that WAL as that won't be required downstream. + * + * The conflict detection slot is not affected by concerns related to WALs + * as it only retains the dead tuples. It is created here for consistency. + * Note that the new conflict detection slot uses the latest transaction + * ID as xmin, so it cannot protect dead tuples that existed before the + * upgrade. Additionally, commit timestamps and origin data are not + * preserved during the upgrade. So, even after creating the slot, the + * upgraded subscriber may be unable to detect conflicts or log relevant + * commit timestamps and origins when applying changes from the publisher + * occurred before the upgrade especially if those changes were not + * replicated. It can only protect tuples that might be deleted after the + * new cluster starts. */ - if (count_old_cluster_logical_slots()) + if (migrate_logical_slots || old_cluster.sub_retain_dead_tuples) { start_postmaster(&new_cluster, true); - create_logical_replication_slots(); + + if (migrate_logical_slots) + create_logical_replication_slots(); + + if (old_cluster.sub_retain_dead_tuples) + create_conflict_detection_slot(); + stop_postmaster(false); } @@ -1025,3 +1048,24 @@ create_logical_replication_slots(void) return; } + +/* + * create_conflict_detection_slot() + * + * Create a replication slot to retain information necessary for conflict + * detection such as dead tuples, commit timestamps, and origins, for migrated + * subscriptions with retain_dead_tuples enabled. + */ +static void +create_conflict_detection_slot(void) +{ + PGconn *conn_new_template1; + + prep_status("Creating the replication conflict detection slot"); + + conn_new_template1 = connectToServer(&new_cluster, "template1"); + PQclear(executeQueryOrDie(conn_new_template1, "SELECT pg_catalog.binary_upgrade_create_conflict_detection_slot()")); + PQfinish(conn_new_template1); + + check_ok(); +} |