From 2d7e591007a6f44e5e27e2b6c1098483105c0d10 Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Wed, 17 Aug 2016 13:15:03 -0700 Subject: [PATCH] Properly re-initialize replication slot shared memory upon creation. Slot creation did not clear all fields upon creation. After start the memory is zeroed, but when a physical replication slot was created in the shared memory of a previously existing logical slot, catalog_xmin would not be cleared. That in turn would prevent vacuum from doing its duties. To fix initialize all the fields. To make similar future bugs less likely, zero all of ReplicationSlotPersistentData, and re-order the rest of the initialization to be in struct member order. Analysis: Andrew Gierth Reported-By: md@chewy.com Author: Michael Paquier Discussion: <20160705173502.1398.70934@wrigleys.postgresql.org> Backpatch: 9.4, where replication slots were introduced --- src/backend/replication/slot.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 2fb7c17d7d..0b2575ee9d 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -272,12 +272,22 @@ ReplicationSlotCreate(const char *name, bool db_specific, */ Assert(!slot->in_use); Assert(slot->active_pid == 0); - slot->data.persistency = persistency; - slot->data.xmin = InvalidTransactionId; - slot->effective_xmin = InvalidTransactionId; + + /* first initialize persistent data */ + memset(&slot->data, 0, sizeof(ReplicationSlotPersistentData)); StrNCpy(NameStr(slot->data.name), name, NAMEDATALEN); slot->data.database = db_specific ? MyDatabaseId : InvalidOid; - slot->data.restart_lsn = InvalidXLogRecPtr; + slot->data.persistency = persistency; + + /* and then data only present in shared memory */ + slot->just_dirtied = false; + slot->dirty = false; + slot->effective_xmin = InvalidTransactionId; + slot->effective_catalog_xmin = InvalidTransactionId; + slot->candidate_catalog_xmin = InvalidTransactionId; + slot->candidate_xmin_lsn = InvalidXLogRecPtr; + slot->candidate_restart_valid = InvalidXLogRecPtr; + slot->candidate_restart_lsn = InvalidXLogRecPtr; /* * Create the slot on disk. We haven't actually marked the slot allocated -- 2.40.0