[mongo] collect additional wiredtiger cache metrics (#18052)

* collect additional wiredtiger cache metrics

* add changelog

mongo/changelog.d/18052.added

@@ -0,0 +1,4 @@
+Collects 3 additional WiredTiger cache metrics from serverStatus
+- wiredtiger.cache.bytes_read_into_cache
+- wiredtiger.cache.bytes_written_from_cache
+- wiredtiger.cache.pages_requested_from_cache

mongo/datadog_checks/mongo/metrics.py

@@ -260,6 +260,8 @@
 """
 WIREDTIGER_METRICS = {
     "wiredTiger.cache.bytes currently in the cache": (GAUGE, "wiredTiger.cache.bytes_currently_in_cache"),
+    "wiredTiger.cache.bytes read into cache": GAUGE,
+    "wiredTiger.cache.bytes written from cache": GAUGE,
     "wiredTiger.cache.failed eviction of pages that exceeded the in-memory maximum": (
         RATE,
         "wiredTiger.cache.failed_eviction_of_pages_exceeding_the_in-memory_maximum",
@@ -270,6 +272,7 @@
     "wiredTiger.cache.modified pages evicted": GAUGE,
     "wiredTiger.cache.pages read into cache": GAUGE,
     "wiredTiger.cache.pages written from cache": GAUGE,
+    "wiredTiger.cache.pages requested from the cache": (GAUGE, "wiredTiger.cache.pages_requested_from_cache"),
     "wiredTiger.cache.pages currently held in the cache": (GAUGE, "wiredTiger.cache.pages_currently_held_in_cache"),
     "wiredTiger.cache.pages evicted because they exceeded the in-memory maximum": (
         RATE,

mongo/metadata.csv

@@ -253,6 +253,8 @@ mongodb.usage.writelock.count,gauge,,lock,,Number of write locks since server st
 mongodb.usage.writelock.countps,gauge,,lock,second,Number of write locks per second,0,mongodb,,,
 mongodb.usage.writelock.time,gauge,,microsecond,,Total time spent performing write locks in microseconds,-1,mongodb,,,
 mongodb.wiredtiger.cache.bytes_currently_in_cache,gauge,,byte,,Size of the data currently in cache.,0,mongodb,bytes currently in the cache,,
+mongodb.wiredtiger.cache.bytes_read_into_cache,gauge,,byte,,Number of bytes read into the cache.,-1,mongodb,bytes read into cache,,
+mongodb.wiredtiger.cache.bytes_written_from_cache,gauge,,byte,,Number of bytes written from the cache.,-1,mongodb,bytes written from cache,,
 mongodb.wiredtiger.cache.failed_eviction_of_pages_exceeding_the_in_memory_maximumps,gauge,,page,second,"Number of failed eviction of pages that exceeded the in-memory maximum, per second.",-1,mongodb,cache failed eviction of pages exceeding in-memory maximum ps,,
 mongodb.wiredtiger.cache.in_memory_page_splits,gauge,,split,,In-memory page splits.,0,mongodb,cache in-memory page splits.,,
 mongodb.wiredtiger.cache.maximum_bytes_configured,gauge,,byte,,Maximum cache size.,0,mongodb,cache maximum bytes configured,,
@@ -262,6 +264,7 @@ mongodb.wiredtiger.cache.pages_currently_held_in_cache,gauge,,page,,Number of pa
 mongodb.wiredtiger.cache.pages_evicted_by_application_threadsps,gauge,,page,second,Number of page evicted by application threads per second.,-1,mongodb,pages evicted by application threads ps,,
 mongodb.wiredtiger.cache.pages_evicted_exceeding_the_in_memory_maximumps,gauge,,page,second,"Number of pages evicted because they exceeded the cache in-memory maximum, per second.",-1,mongodb,pages evicted exceeding in-memory maximum ps,,
 mongodb.wiredtiger.cache.pages_read_into_cache,gauge,,page,,Number of pages read into the cache.,-1,mongodb,pages read cache,,
+mongodb.wiredtiger.cache.pages_requested_from_cache,gauge,,page,,Number of pages requested from the cache.,-1,mongodb,pages requested from cache,,
 mongodb.wiredtiger.cache.pages_written_from_cache,gauge,,page,,Number of pages writtent from the cache,-1,mongodb,pages written cache,,
 mongodb.wiredtiger.cache.tracked_dirty_bytes_in_cache,gauge,,byte,,Size of the dirty data in the cache.,0,mongodb,tracked dirty bytes in cache,,
 mongodb.wiredtiger.cache.unmodified_pages_evicted,gauge,,page,,"Number of pages, that were not modified, evicted from the cache.",0,mongodb,cache unmodified pages evicted,,

mongo/tests/fixtures/serverStatus

@@ -1068,6 +1068,7 @@
              "pages currently held in the cache": 12,
              "pages read into cache": 12,
              "pages read into cache requiring lookaside entries": 12,
+             "pages requested from the cache": 12,
              "pages written from cache": 12,
              "page written requiring lookaside records": 12,
              "pages written requiring in-memory restoration": 12

mongo/tests/results/metrics-serverStatus.json

@@ -1215,6 +1215,22 @@
             "server:mongodb://testUser2:*****@localhost:27017/test"
         ]
     },
+    {
+        "name": "mongodb.wiredtiger.cache.bytes_read_into_cache",
+        "type": 0,
+        "value": 12.0,
+        "tags": [
+            "server:mongodb://testUser2:*****@localhost:27017/test"
+        ]
+    },
+    {
+        "name": "mongodb.wiredtiger.cache.bytes_written_from_cache",
+        "type": 0,
+        "value": 12.0,
+        "tags": [
+            "server:mongodb://testUser2:*****@localhost:27017/test"
+        ]
+    },
     {
         "name": "mongodb.wiredtiger.cache.failed_eviction_of_pages_exceeding_the_in_memory_maximumps",
         "type": 1,
@@ -1263,6 +1279,14 @@
             "server:mongodb://testUser2:*****@localhost:27017/test"
         ]
     },
+    {
+        "name": "mongodb.wiredtiger.cache.pages_requested_from_cache",
+        "type": 0,
+        "value": 12.0,
+        "tags": [
+            "server:mongodb://testUser2:*****@localhost:27017/test"
+        ]
+    },
     {
         "name": "mongodb.wiredtiger.cache.pages_written_from_cache",
         "type": 0,