Deprecate the old exporter batch configuration section

Author: dmitryax

.chloggen/deprecate-old-batcher.yaml

@@ -0,0 +1,29 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: deprecation
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: exporterhelper
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: "Deprecate configuring exporter batching separately. Use `sending_queue::batch` instead."
+
+# One or more tracking issues or pull requests related to the change
+issues: []
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: |
+  Moving the batching configuration to `sending_queue::batch` requires setting `sending_queue::sizer` to `items`
+  which means that `sending_queue::queue_size` needs to be also increased by the average batch size number (roughly 
+  x5000 for the default batching configuration).
+  See https://github.com/open-telemetry/opentelemetry-collector/tree/main/exporter/exporterhelper#configuration
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

exporter/exporterhelper/internal/queuebatch/queue_batch.go

@@ -41,6 +41,8 @@ func NewQueueBatchLegacyBatcher(
 	cfg Config,
 	next sender.SendFunc[request.Request],
 ) (*QueueBatch, error) {
+	set.Telemetry.Logger.Warn("Configuring the exporter batcher capability separately is now deprecated. " +
+		"Use sending_queue::batch instead.")
 	return newQueueBatch(set, cfg, next, true)
 }