[[breaking-changes-7.4]] == Breaking changes in 7.4 ++++ 7.4 ++++ This section discusses the changes that you need to be aware of when migrating your application to Elasticsearch 7.4. See also <> and <>. coming[7.4.0] //NOTE: The notable-breaking-changes tagged regions are re-used in the //Installation and Upgrade Guide //tag::notable-breaking-changes[] // end::notable-breaking-changes[] [[breaking_74_plugin_changes]] === Plugins changes [float] ==== TokenizerFactory changes TokenizerFactory now has a `name()` method that must be implemented. Most plugin-provided TokenizerFactory implementations will extend `AbstractTokenizerFactory`, which now takes a `name` parameter in its constructor. [float] [[breaking_74_search_changes]] === Search Changes [float] ==== Forbid empty doc values in vector functions If a document doesn't have a value for a vector field (dense_vector or sparse_vector) on which a vector function is executed, an error will be thrown. [float] [[breaking_74_snapshots_changes]] === Snapshot and Restore changes [float] ==== The S3 repository plugin uses the DNS style access pattern by default Starting in version 7.4 the `repository-s3` plugin does not use the now-deprecated path-style access pattern by default. In versions 7.0, 7.1, 7.2 and 7.3 the `repository-s3` plugin always used the path-style access pattern. This is a breaking change for deployments that only support path-style access but which are recognized as supporting DNS-style access by the AWS SDK. If your deployment only supports path-style access and is affected by this change then you must configure the S3 client setting `path_style_access` to `true`. This breaking change was made necessary by https://aws.amazon.com/blogs/aws/amazon-s3-path-deprecation-plan-the-rest-of-the-story/[AWS's announcement] that the path-style access pattern is deprecated and will be unsupported on buckets created after September 30th 2020. [float] [[breaking_80_http_changes]] === HTTP changes [float] ==== Changes to Encoding Plus Signs in URLs Starting in version 7.4, a `+` in a URL will be encoded as `%2B` by all REST API functionality. Prior versions handled a `+` as a single space. If your application requires handling `+` as a single space you can return to the old behaviour by setting the system property `es.rest.url_plus_as_space` to `true`. Note that this behaviour is deprecated and setting this system property to `true` will cease to be supported in version 8. [float] [[breaking_74_cluster_changes]] === Cluster changes [float] ==== Rerouting after starting a shard runs at lower priority After starting each shard the elected master node must perform a reroute to search for other shards that could be allocated. In particular, when creating an index it is this task that allocates the replicas once the primaries have started. In versions prior to 7.4 this task runs at priority `URGENT`, but starting in version 7.4 its priority is reduced to `NORMAL`. In a well-configured cluster this reduces the amount of work the master must do, but means that a cluster with a master that is overloaded with other tasks at `HIGH` or `URGENT` priority may take longer to allocate all replicas. Additionally, before 7.4 the `GET _cluster_health?wait_for_no_initializing_shards` and `GET _cluster/health?wait_for_no_relocating_shards` APIs would return only once all pending reroutes have completed too, but starting in version 7.4 if you want to wait for the rerouting process to completely finish you should add the `wait_for_events=languid` query parameter when calling these APIs. [float] [[breaking_74_allocation_changes]] === Allocation changes [float] ==== Auto-release of read-only-allow-delete block If a node exceeds the flood-stage disk watermark then {es} adds the `index.blocks.read_only_allow_delete` block to all of its indices to prevent further writes, as a last-resort attempt to prevent the node completely exhausting its disk space. In earlier versions this block would remain in place until manually removed, causing confusion for users who currently have ample disk space and who are not aware that they nearly ran out at some point in the past. From 7.4 onwards the block is automatically removed when the node drops below the high watermark again, with the expectation that the high watermark is some distance below the flood-stage watermark and therefore the disk space problem is truly resolved. Since this block may be automatically removed, you can no longer rely on adding this block manually to prevent writes to an index. You should use the `index.blocks.read_only` block instead. This behaviour can be disabled by setting the system property `es.disk.auto_release_flood_stage_block` to `false`.