diff options
Diffstat (limited to 'src/include/replication/slot.h')
| -rw-r--r-- | src/include/replication/slot.h | 40 |
1 files changed, 38 insertions, 2 deletions
diff --git a/src/include/replication/slot.h b/src/include/replication/slot.h index eb0b93b1114..e8fc342d1a9 100644 --- a/src/include/replication/slot.h +++ b/src/include/replication/slot.h @@ -21,6 +21,13 @@ #define PG_REPLSLOT_DIR "pg_replslot" /* + * The reserved name for a replication slot used to retain dead tuples for + * conflict detection in logical replication. See + * maybe_advance_nonremovable_xid() for detail. + */ +#define CONFLICT_DETECTION_SLOT "pg_conflict_detection" + +/* * Behaviour of replication slots, upon release or crash. * * Slots marked as PERSISTENT are crash-safe and will not be dropped when @@ -215,6 +222,33 @@ typedef struct ReplicationSlot * recently stopped. */ TimestampTz inactive_since; + + /* + * Latest restart_lsn that has been flushed to disk. For persistent slots + * the flushed LSN should be taken into account when calculating the + * oldest LSN for WAL segments removal. + * + * Do not assume that restart_lsn will always move forward, i.e., that the + * previously flushed restart_lsn is always behind data.restart_lsn. In + * streaming replication using a physical slot, the restart_lsn is updated + * based on the flushed WAL position reported by the walreceiver. + * + * This replication mode allows duplicate WAL records to be received and + * overwritten. If the walreceiver receives older WAL records and then + * reports them as flushed to the walsender, the restart_lsn may appear to + * move backward. + * + * This typically occurs at the beginning of replication. One reason is + * that streaming replication starts at the beginning of a segment, so, if + * restart_lsn is in the middle of a segment, it will be updated to an + * earlier LSN, see RequestXLogStreaming. Another reason is that the + * walreceiver chooses its startpoint based on the replayed LSN, so, if + * some records have been received but not yet applied, they will be + * received again and leads to updating the restart_lsn to an earlier + * position. + */ + XLogRecPtr last_saved_restart_lsn; + } ReplicationSlot; #define SlotIsPhysical(slot) ((slot)->data.database == InvalidOid) @@ -258,7 +292,7 @@ extern PGDLLIMPORT ReplicationSlot *MyReplicationSlot; /* GUCs */ extern PGDLLIMPORT int max_replication_slots; extern PGDLLIMPORT char *synchronized_standby_slots; -extern PGDLLIMPORT int idle_replication_slot_timeout_mins; +extern PGDLLIMPORT int idle_replication_slot_timeout_secs; /* shmem initialization functions */ extern Size ReplicationSlotsShmemSize(void); @@ -284,7 +318,9 @@ extern void ReplicationSlotMarkDirty(void); /* misc stuff */ extern void ReplicationSlotInitialize(void); -extern bool ReplicationSlotValidateName(const char *name, int elevel); +extern bool ReplicationSlotValidateName(const char *name, + bool allow_reserved_name, + int elevel); extern void ReplicationSlotReserveWal(void); extern void ReplicationSlotsComputeRequiredXmin(bool already_locked); extern void ReplicationSlotsComputeRequiredLSN(void); |