[7.8][Transform] fix page size return in cat transform, add dps (#57912)

fixes the page size reported after moving page size to settings(#56007) and
adds documents per second(throttling) to the output.

fixes #56498

Author: Hendrik Muhs

docs/reference/cat/transforms.asciidoc

@@ -20,9 +20,9 @@ Returns configuration and usage information about {transforms}.
 [[cat-transforms-api-prereqs]]
 ==== {api-prereq-title}
 
-* If the {es} {security-features} are enabled, you must have `monitor_transform` 
-cluster privileges to use this API. The built-in `transform_user` role has these 
-privileges. For more information, see <<security-privileges>> and 
+* If the {es} {security-features} are enabled, you must have `monitor_transform`
+cluster privileges to use this API. The built-in `transform_user` role has these
+privileges. For more information, see <<security-privileges>> and
 <<built-in-roles>>.
 
 //[[cat-transforms-api-desc]]
@@ -77,6 +77,10 @@ include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=dest-index]
 `documents_indexed`, `doci`:::
 include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=docs-indexed]
 
+`docs_per_second`, `dps`:::
+(Default)
+include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=transform-settings-docs-per-second]
+
 `documents_processed`, `docp`:::
 include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=docs-processed]
 
@@ -139,7 +143,7 @@ include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=state-transform]
 
 `transform_type`, `tt`:::
 (Default)
-Indicates the type of {transform}: `batch` or `continuous`. 
+Indicates the type of {transform}: `batch` or `continuous`.
 
 `trigger_count`, `tc`:::
 include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=trigger-count]

x-pack/plugin/src/test/resources/rest-api-spec/test/transform/transforms_cat_apis.yml

@@ -55,8 +55,8 @@ teardown:
         transform_id: "airline-transform-stats"
   - match:
       $body: |
-        /^  #id                           \s+ create_time \s+ version \s+ source_index \s+ dest_index              \s+ pipeline \s+ transform_type \s+ frequency \s+ max_page_search_size \s+ state    \n
-            (airline\-transform\-stats    \s+ [^\s]+      \s+ [^\s]+  \s+ airline-data \s+ airline-data-by-airline \s+          \s+ batch          \s+ 1m        \s+ 500                  \s+ STOPPED \n)+  $/
+        /^  #id                           \s+ create_time \s+ version \s+ source_index \s+ dest_index              \s+ pipeline \s+ transform_type \s+ frequency \s+ max_page_search_size \s+ docs_per_second \s+ state    \n
+            (airline\-transform\-stats    \s+ [^\s]+      \s+ [^\s]+  \s+ airline-data \s+ airline-data-by-airline \s+          \s+ batch          \s+ 1m        \s+ 500                  \s+ -               \s+ STOPPED \n)+  $/
 
 ---
 "Test cat transform stats with column selection":
@@ -95,8 +95,8 @@ teardown:
         v: true
   - match:
       $body: |
-        /^   id                        \s+ create_time \s+ version \s+ source_index                    \s+ dest_index                    \s+ pipeline \s+ description \s+ transform_type \s+ frequency \s+ max_page_search_size \s+ state   \n
-            (airline\-transform\-batch \s+ [^\s]+      \s+ [^\s]+  \s+ airline-data,airline-data-other \s+ airline-data-by-airline-batch \s+          \s+ description \s+ batch          \s+ 1m        \s+ 500                  \s+ STOPPED \n)+  $/
+        /^   id                        \s+ create_time \s+ version \s+ source_index                    \s+ dest_index                    \s+ pipeline \s+ description \s+ transform_type \s+ frequency \s+ max_page_search_size \s+ docs_per_second \s+ state   \n
+            (airline\-transform\-batch \s+ [^\s]+      \s+ [^\s]+  \s+ airline-data,airline-data-other \s+ airline-data-by-airline-batch \s+          \s+ description \s+ batch          \s+ 1m        \s+ 500                  \s+ -               \s+ STOPPED \n)+  $/
   - do:
       transform.delete_transform:
         transform_id: "airline-transform-batch"
@@ -131,8 +131,8 @@ teardown:
         v: true
   - match:
       $body: |
-        /^   id                             \s+ create_time \s+ version \s+ source_index                    \s+ dest_index                         \s+ pipeline \s+ description \s+ transform_type \s+ frequency \s+ max_page_search_size \s+ state   \n
-            (airline\-transform\-continuous \s+ [^\s]+      \s+ [^\s]+  \s+ airline-data,airline-data-other \s+ airline-data-by-airline-continuous \s+          \s+ description \s+ continuous     \s+ 10s       \s+ 500                  \s+ STOPPED \n)+  $/
+        /^   id                             \s+ create_time \s+ version \s+ source_index                    \s+ dest_index                         \s+ pipeline \s+ description \s+ transform_type \s+ frequency \s+ max_page_search_size \s+ docs_per_second \s+ state   \n
+            (airline\-transform\-continuous \s+ [^\s]+      \s+ [^\s]+  \s+ airline-data,airline-data-other \s+ airline-data-by-airline-continuous \s+          \s+ description \s+ continuous     \s+ 10s       \s+ 500                  \s+ -               \s+ STOPPED \n)+  $/
   - do:
       transform.delete_transform:
         transform_id: "airline-transform-continuous"

x-pack/plugin/transform/src/main/java/org/elasticsearch/xpack/transform/Transform.java

@@ -28,6 +28,7 @@
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.settings.SettingsFilter;
 import org.elasticsearch.common.settings.SettingsModule;
+import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry.Entry;
 import org.elasticsearch.env.Environment;
@@ -132,6 +133,8 @@ public class Transform extends Plugin implements SystemIndexPlugin, PersistentTa
     private final SetOnce<TransformServices> transformServices = new SetOnce<>();
 
     public static final int DEFAULT_FAILURE_RETRIES = 10;
+    public static final Integer DEFAULT_INITIAL_MAX_PAGE_SEARCH_SIZE = Integer.valueOf(500);
+    public static final TimeValue DEFAULT_TRANSFORM_FREQUENCY = TimeValue.timeValueMillis(60000);
 
     // How many times the transform task can retry on an non-critical failure
     public static final Setting<Integer> NUM_FAILURE_RETRIES_SETTING = Setting.intSetting(
@@ -283,12 +286,7 @@ public Collection<Object> createComponents(
 
         TransformConfigManager configManager = new IndexBasedTransformConfigManager(client, xContentRegistry);
         TransformAuditor auditor = new TransformAuditor(client, clusterService.getNodeName());
-        TransformCheckpointService checkpointService = new TransformCheckpointService(
-            settings,
-            clusterService,
-            configManager,
-            auditor
-        );
+        TransformCheckpointService checkpointService = new TransformCheckpointService(settings, clusterService, configManager, auditor);
         SchedulerEngine scheduler = new SchedulerEngine(settings, Clock.systemUTC());
 
         transformServices.set(new TransformServices(configManager, checkpointService, auditor, scheduler));