postgres.git / summary / log / commit / refs

commit    690a2fb90ef47a3a0750b70e2abf13bbb82466ff
Author:   Andres Freund <andres@anarazel.de>
Date:     Wed Aug 17 20:15:04 2016 +0000

    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 | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index 839ead0e330..b8761e4f88f 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -263,13 +263,22 @@ ReplicationSlotCreate(const char *name, bool db_specific,
 	 */
 	Assert(!slot->in_use);
 	Assert(!slot->active);
+
+	/* 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.persistency = persistency;
-	slot->data.xmin = InvalidTransactionId;
+
+	/* and then data only present in shared memory */
+	slot->just_dirtied = false;
+	slot->dirty = false;
 	slot->effective_xmin = InvalidTransactionId;
-	strncpy(NameStr(slot->data.name), name, NAMEDATALEN);
-	NameStr(slot->data.name)[NAMEDATALEN - 1] = '\0';
-	slot->data.database = db_specific ? MyDatabaseId : InvalidOid;
-	slot->data.restart_lsn = InvalidXLogRecPtr;
+	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


[parent: 3fa8ec44d1b9]