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-rw-r--r--src/backend/access/heap/README.tuplock7
1 files changed, 4 insertions, 3 deletions
diff --git a/src/backend/access/heap/README.tuplock b/src/backend/access/heap/README.tuplock
index d03ddf6cdcc..6441e8baf0e 100644
--- a/src/backend/access/heap/README.tuplock
+++ b/src/backend/access/heap/README.tuplock
@@ -146,9 +146,10 @@ The following infomask bits are applicable:
FOR UPDATE; this is implemented by the HEAP_KEYS_UPDATED bit.
- HEAP_KEYS_UPDATED
- This bit lives in t_infomask2. If set, indicates that the XMAX updated
- this tuple and changed the key values, or it deleted the tuple.
- It's set regardless of whether the XMAX is a TransactionId or a MultiXactId.
+ This bit lives in t_infomask2. If set, indicates that the operation(s) done
+ by the XMAX compromise the tuple key, such as a SELECT FOR UPDATE, an UPDATE
+ that modifies the columns of the key, or a DELETE. It's set regardless of
+ whether the XMAX is a TransactionId or a MultiXactId.
We currently never set the HEAP_XMAX_COMMITTED when the HEAP_XMAX_IS_MULTI bit
is set.