diff options
Diffstat (limited to 'src/include/replication/reorderbuffer.h')
| -rw-r--r-- | src/include/replication/reorderbuffer.h | 39 |
1 files changed, 25 insertions, 14 deletions
diff --git a/src/include/replication/reorderbuffer.h b/src/include/replication/reorderbuffer.h index 01eabfb7be7..04ff002990d 100644 --- a/src/include/replication/reorderbuffer.h +++ b/src/include/replication/reorderbuffer.h @@ -32,12 +32,22 @@ typedef struct ReorderBufferTupleBuf char data[MaxHeapTupleSize]; } ReorderBufferTupleBuf; -/* types of the change passed to a 'change' callback */ +/* + * Types of the change passed to a 'change' callback. + * + * For efficiency and simplicity reasons we want to keep Snapshots, CommandIds + * and ComboCids in the same list with the user visible INSERT/UPDATE/DELETE + * changes. Users of the decoding facilities will never see changes with + * *_INTERNAL_* actions. + */ enum ReorderBufferChangeType { REORDER_BUFFER_CHANGE_INSERT, REORDER_BUFFER_CHANGE_UPDATE, - REORDER_BUFFER_CHANGE_DELETE + REORDER_BUFFER_CHANGE_DELETE, + REORDER_BUFFER_CHANGE_INTERNAL_SNAPSHOT, + REORDER_BUFFER_CHANGE_INTERNAL_COMMAND_ID, + REORDER_BUFFER_CHANGE_INTERNAL_TUPLECID }; /* @@ -51,13 +61,8 @@ typedef struct ReorderBufferChange { XLogRecPtr lsn; - /* type of change */ - union - { - enum ReorderBufferChangeType action; - /* do not leak internal enum values to the outside */ - int action_internal; - }; + /* The type of change. */ + enum ReorderBufferChangeType action; /* * Context data for the change, which part of the union is valid depends @@ -65,7 +70,7 @@ typedef struct ReorderBufferChange */ union { - /* old, new tuples when action == *_INSERT|UPDATE|DELETE */ + /* Old, new tuples when action == *_INSERT|UPDATE|DELETE */ struct { /* relation that has been changed */ @@ -76,13 +81,19 @@ typedef struct ReorderBufferChange ReorderBufferTupleBuf *newtuple; } tp; - /* new snapshot */ + /* New snapshot, set when action == *_INTERNAL_SNAPSHOT */ Snapshot snapshot; - /* new command id for existing snapshot in a catalog changing tx */ + /* + * New command id for existing snapshot in a catalog changing tx. Set + * when action == *_INTERNAL_COMMAND_ID. + */ CommandId command_id; - /* new cid mapping for catalog changing transaction */ + /* + * New cid mapping for catalog changing transaction, set when action + * == *_INTERNAL_TUPLECID. + */ struct { RelFileNode node; @@ -91,7 +102,7 @@ typedef struct ReorderBufferChange CommandId cmax; CommandId combocid; } tuplecid; - }; + } data; /* * While in use this is how a change is linked into a transactions, |