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commit 2be6869ddfd8b0f4c22c25eab5d293b2e33f108f
Author: Hao Hao <hao.hao@cloudera.com>
AuthorDate: Fri Mar 15 13:51:06 2019 -0700
update outdated comments for Read-your-writes scan
Change-Id: Ia5eaa8c64edcb35a6936d8699396d45ef8457dea
Reviewed-on: http://gerrit.cloudera.org:8080/12768
Reviewed-by: Adar Dembo <adar@cloudera.com>
Tested-by: Kudu Jenkins
Reviewed-by: Alexey Serbin <aserbin@cloudera.com>
---
src/kudu/client/client.h | 38 +++-----------------------------------
1 file changed, 3 insertions(+), 35 deletions(-)
diff --git a/src/kudu/client/client.h b/src/kudu/client/client.h
index 780967c..a5ad313 100644
--- a/src/kudu/client/client.h
+++ b/src/kudu/client/client.h
@@ -497,38 +497,9 @@ class KUDU_EXPORT KuduClient : public sp::enable_shared_from_this<KuduClient>
{
/// Get the highest HybridTime timestamp observed by the client.
///
- /// The latest observed timestamp can be used to start a snapshot scan on a
- /// table which is guaranteed to contain all data written or previously read
- /// by this client. See KuduScanner for more details on timestamps.
- ///
- /// How to get Read-Your-Writes consistency:
- /// the code snippet below uses KuduClient::GetLatestObservedTimestamp() along
- /// with KuduScanner::SetSnapshotRaw() to perform READ_AT_SNAPSHOT scan
- /// containing the data which has just been written. Notice extra 1
- /// added to the timestamp passed to KuduScanner::SetSnapshotRaw():
- /// @code
- /// shared_ptr<KuduClient> client;
- /// ... // open/initialize the client
- /// shared_ptr<KuduSession> session(client->NewSession());
- /// ... // set Kudu session properties
- /// shared_ptr<KuduTable> table;
- /// ... // open the table
- /// unique_ptr<KuduInsert> insert_op(table->NewInsert());
- /// ... // populate new insert operation with data
- /// RETURN_NOT_OK(session->Apply(insert_op.release()));
- /// RETURN_NOT_OK(session->Flush());
- /// uint64_t snapshot_timestamp = client->GetLatestObservedTimestamp() + 1;
- /// KuduScanner scanner(table.get());
- /// RETURN_NOT_OK(scanner.SetSnapshotRaw(snapshot_timestamp));
- /// RETURN_NOT_OK(scanner.SetSelection(KuduClient::LEADER_ONLY));
- /// RETURN_NOT_OK(scanner.SetReadMode(KuduScanner::READ_AT_SNAPSHOT));
- /// RETURN_NOT_OK(scanner.Open());
- /// ... // retrieve scanned rows
- /// @endcode
- /// There are currently races in which, in rare occasions, Read-Your-Writes
- /// consistency might not hold even in this case. These are being
- /// taken care of as part of
- /// <a href="https://issues.apache.org/jira/browse/KUDU-430">KUDU-430</a>
+ /// This is useful when retrieving timestamp from one client and
+ /// forwarding it to another to enforce external consistency when
+ /// using KuduSession::CLIENT_PROPAGATED external consistency mode.
///
/// @note This method is experimental and will either disappear or
/// change in a future release.
@@ -2158,9 +2129,6 @@ class KUDU_EXPORT KuduScanner {
/// Set snapshot timestamp for scans in @c READ_AT_SNAPSHOT mode (raw).
///
- /// See KuduClient::GetLatestObservedTimestamp() for details on how to
- /// use this method to achieve Read-Your-Writes behavior.
- ///
/// @note This method is experimental and will either disappear or
/// change in a future release.
///
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