Release Notes

Release Notes

Couchbase Server 5.5.0 Beta is a significant update of the Couchbase Data Platform. This release specifically highlights agility, performance, and manageability and includes enhancements to existing services as well as new server and SDK components. Take a look at What's New? for a list of new features and improvements that are available in this release.

Couchbase Server 5.5.0 Beta was released in April 2018.


This pre-release version of Couchbase Server 5.5 (Beta) is intended for development purposes only. Some features are still in development and may have some rough edges and bugs, and may change significantly before the final GA release. This pre-release version is not supported in production.

The pre-release versions do not support upgrading from an earlier version of Couchbase Server.

Major Behavior Changes

Issue Description
MB-28778 The default number of Data Service worker threads has been increased; from 3/4 of the number of available CPU threads, to 7/8 of the number of available CPU threads (minimum of 4 in both cases). This makes better use of the available CPU resource, particularly on larger systems, as such users may see an increase in CPU utilization on such systems.

Prior to 5.5, the mctimings command defined the request start as the time when the 24 byte request header had been read by the Data Service. However, many requests contain a body which also needs to be read before a request can be processed. As such, the reported duration didn't accurately reflect how long the server actually spent processing a request, if it was still waiting for the body to be received from the network.

In 5.5, the definition of request start has been changed to be when the header and body have both been read. This has the effect of more accurately reflecting the time spent by the Data Service in servicing a request, as the time the body spends in transit over the network is no longer included. As a result command timings for affected request will have shorter durations compared to how they were measured before 5.5.

MB-27060 The Couchbase Server 5.5 Windows installer package no longer bundles the DLL dbghelp.dll which is required by Breakpad to produce dumps on Windows platforms. Starting version 5.5, Breakpad will pick the DLL (dbghelp.dll) that is shipped with the OS.

Known Issues

Cross Data-center Replication (XDCR)

Issue Description
MB-29209, MB-29205, MB-29113, MB-29040 Summary: There are a number of open issues in Couchbase Server, which can cause rebalance to fail from time to time. These issues are being worked on and will be addressed for GA.

Workaround: Rerun rebalance as the subsequent rebalance operations succeed in most cases.

MB-27719 Summary: The cbrecovery command throws an exception when recovering data from a cluster that has failed over nodes.

Administration/Cluster Management

Issue Description
MB-28417 Summary: The permissions assigned to the cluster_admin role have been downgraded. As a result, The cluster_admin role no longer has FTS write permissions used to create FTS searches.

Workaround: Add the fts_admin role as required.

MB-23074 Summary: Performance issues may be observed when running Couchbase Server on CentOS 7.3 with kernel 3.10.0-514.6.
MB-17571 Summary: On an undersized node, the default memory quota assigned to all the selected services by the server might result in a failure.

Workaround: Adjust the memory allocations appropriately to work around this issue.

Data Service

Issue Description
MB-29227 Summary: Couchbase Server can get into a livelock state due to high checkpoint memory usage.
MB-28868 Summary: The index service undergoes a race condition in the storage engine which leads to a crash. The crash is most likely to happen if the index service is restarted with existing build indexes and they continue to process mutations after the index service restarts.

Eventing Service

Issue Description
MB-29235 Summary: Eventing does not retry bucket operation failures that are determined by the appropriate LCB macro to be retriable.
MB-29147 Summary: Rebalance of KV/Eventing nodes can hang if the cluster contains Eventing nodes due to stale authentication info with the GoCB SDK.
MB-29076 Summary: The signatures of docTimer and cronTimer functions are not consistent.
MB-28968 Summary: Rebalance of KV/Eventing nodes can hang if the cluster contains Eventing nodes.
MB-28779 Summary: If the handler code is not idempotent, there could be more docs on the destination bucket than expected post rebalance.
MB-28775 Summary: On Windows, there could be orphan processes with .rbf extension running even after uninstalling Couchbase Server.

Workaround: Kill all eventing-consumer.exe processes before reinstalling Couchbase Server.

MB-28667 Summary: In some circumstances, like function undergoing bootstrap or buckets referenced by the function (source, metadata, destination) get flushed or deleted, the function cannot be undeployed.
MB-28550 Summary: After restoring from a enterprise backup of eventing functions, eventing service will not process mutations in the destination cluster.
MB-28315 Summary: Redeploying a function results in the application log being truncated instead of appending to the existing log.
MB-27814 Summary: When there are multiple functions being deployed, undeployment does not happen until all functions are deployed.
MB-27679 Summary: The Eventing service can crash when processing documents in source buckets with size > 1 MB.
MB-27559 Summary: Benign panics can be seen in the eventing service logs during undeployment.
MB-27491 Summary: Failed rebalance, when retried, can hang.
MB-27454 Summary: Rebalance-in of a data(KV) node after recovery from failover may hang if eventing service is processing mutations.

Full-text Search Service

Issue Description
MB-29142 Summary:
MB-28894 Summary:
MB-28847 Summary: The memory usage during index build overshoots the RAM quota.
MB-28468 Summary: The full-text search service repeatedly attempts to setup DCP streams to non-existing vBuckets.
MB-25714 Summary: On Windows platform, a very high memory/CPU usage may be observed when search service is indexing.

Indexing Service

Issue Description
MB-28139 Summary: If the index files are corrupted, the index service may continue to crash.

Workaround: Failover the indexer node, or manually delete the corrupt index files from the server.

MB-19869 Summary: Rebalance fails when taking out failed over nodes running views, in certain circumstances.


Issue Description
MB-28337 Summary: The cbworkloadgen utility fails to load large number of documents when IPv6 was enabled.

Analytics Service (Developer Preview)

Issue Description

Summary: It is possible for a rebalance of the Analytics nodes to always fail if:

  • a bucket is in the disconnected state, and
  • the Analytics nodes are at different DCP states.
In that case a common DCP state (required for rebalancing) cannot be achieved as no new DCP mutations will be received by the Analytics nodes.

Fixed Issues

Query Service

Issue Description
MB-25901 Fixed an issue where the ORDER BY operator proceeded to sort even after being stopped and could lead to crashes.

Deprecated Features and Platforms

The following functionality is deprecated, will be deprecated or is unsupported.

  • Server side moxi or buckets with custom server side moxi ports are deprecated and may be removed from the product in the future.