Deprecate vttablet metrics QueryCacheXX and rename to QueryPlanCacheXX

changelog/20.0/20.0.0/release_notes.md

@@ -360,8 +360,12 @@ You can now run `VDiff`s on OnlineDDL schema change migrations, which are not ye
 
 VTTablet exposes two new counter stats:
 
- * `QueryCacheHits`: Query engine query cache hits
- * `QueryCacheMisses`: Query engine query cache misses
+ * `QueryCacheHits`: Query engine query plan cache hits
+ * `QueryCacheMisses`: Query engine query plan cache misses
+
+> [!NOTE]
+> `QueryCache` does not refer to a query cache, but to a query plan cache.
+> In v21, these metrics will be deprecated and replaced by `QueryPlanCacheHits` and `QueryPlanCacheMisses`.
 
 ### <a id="vttablet-query-text-characters-processed"/>VTTablet Query Text Characters Processed
 

changelog/20.0/20.0.0/summary.md

@@ -359,8 +359,12 @@ You can now run `VDiff`s on OnlineDDL schema change migrations, which are not ye
 
 VTTablet exposes two new counter stats:
 
- * `QueryCacheHits`: Query engine query cache hits
- * `QueryCacheMisses`: Query engine query cache misses
+ * `QueryCacheHits`: Query engine query plan cache hits
+ * `QueryCacheMisses`: Query engine query plan cache misses
+
+> [!NOTE]
+> `QueryCache` does not refer to a query cache, but to a query plan cache.
+> In v21, these metrics will be deprecated and replaced by `QueryPlanCacheHits` and `QueryPlanCacheMisses`.
 
 ### <a id="vttablet-query-text-characters-processed"/>VTTablet Query Text Characters Processed
 

changelog/21.0/21.0.0/summary.md

@@ -4,13 +4,31 @@
 ### Table of Contents
 
 - **[Major Changes](#major-changes)**
+  - **[Deprecations](#deprecations)**
+    - [Metrics](#deprecations-metrics) 
   - **[Deletions](#deletions)** 
     - [Deletion of deprecated metrics](#metric-deletion)
   - **[Breaking changes](#breaking-changes)**
 
 ## <a id="major-changes"/>Major Changes
 
-### <a id="deletions"/>Deletion
+### <a id="deprecations"/>Deprecations
+
+#### <a id="deprecations-metrics"/>Metrics
+
+The following metrics are now deprecated, if provided please use their replacement.
+
+| Component  |      Metric Name      |        Replaced By        |
+|------------|:---------------------:|:-------------------------:|
+| `vttablet` |  `QueryCacheLength`   |  `QueryPlanCacheLength`   |
+| `vttablet` |   `QueryCacheSize`    |   `QueryPlanCacheSize`    |
+| `vttablet` | `QueryCacheCapacity`  | `QueryPlanCacheCapacity`  |
+| `vttablet` | `QueryCacheEvictions` | `QueryPlanCacheEvictions` |
+| `vttablet` |   `QueryCacheHits`    |   `QueryPlanCacheHits`    |
+| `vttablet` |  `QueryCacheMisses`   |  `QueryPlanCacheMisses`   |
+
+
+### <a id="deletions"/>Deletions
 
 #### <a id="metric-deletion"/>Deletion of deprecated metrics
 

config/tablet/default.yaml

@@ -99,7 +99,6 @@ hotRowProtection:
 consolidator: enable|disable|notOnPrimary # enable-consolidator, enable-consolidator-replicas
 passthroughDML: false                    # queryserver-config-passthrough-dmls
 streamBufferSize: 32768                  # queryserver-config-stream-buffer-size
-queryCacheSize: 5000                     # queryserver-config-query-cache-size
 schemaReloadIntervalSeconds: 1800        # queryserver-config-schema-reload-time
 watchReplication: false                  # watch_replication_stream
 terseErrors: false                       # queryserver-config-terse-errors

doc/design-docs/TabletServerParamsAsYAML.md

@@ -126,7 +126,6 @@ heartbeatIntervalMilliseconds: 0         # heartbeat_enable, heartbeat_interval
 shutdownGracePeriodSeconds: 0            # transaction_shutdown_grace_period
 passthroughDML: false                    # queryserver-config-passthrough-dmls
 streamBufferSize: 32768                  # queryserver-config-stream-buffer-size
-queryCacheSize: 5000                     # queryserver-config-query-cache-size
 schemaReloadIntervalSeconds: 1800        # queryserver-config-schema-reload-time
 watchReplication: false                  # watch_replication_stream
 terseErrors: false                       # queryserver-config-terse-errors

go/vt/vttablet/endtoend/config_test.go

@@ -192,7 +192,7 @@ func TestConsolidatorReplicasOnly(t *testing.T) {
 	}
 }
 
-func TestQueryPlanCache(t *testing.T) {
+func TestQueryPlanCacheSize(t *testing.T) {
 	var cachedPlanSize = int((&tabletserver.TabletPlan{}).CachedSize(true))
 
 	// sleep to avoid race between SchemaChanged event clearing out the plans cache which breaks this test
@@ -211,19 +211,19 @@ func TestQueryPlanCache(t *testing.T) {
 	assert.Equal(t, 1, framework.Server.QueryPlanCacheLen())
 
 	vend := framework.DebugVars()
-	assert.GreaterOrEqual(t, framework.FetchInt(vend, "QueryCacheSize"), cachedPlanSize)
+	assert.GreaterOrEqual(t, framework.FetchInt(vend, "QueryPlanCacheSize"), cachedPlanSize)
 
 	_, _ = client.Execute("select * from vitess_test where intval=:ival2", bindVars)
 	require.Equal(t, 2, framework.Server.QueryPlanCacheLen())
 
 	vend = framework.DebugVars()
-	assert.GreaterOrEqual(t, framework.FetchInt(vend, "QueryCacheSize"), 2*cachedPlanSize)
+	assert.GreaterOrEqual(t, framework.FetchInt(vend, "QueryPlanCacheSize"), 2*cachedPlanSize)
 
 	_, _ = client.Execute("select * from vitess_test where intval=1", bindVars)
 	require.Equal(t, 3, framework.Server.QueryPlanCacheLen())
 
 	vend = framework.DebugVars()
-	assert.GreaterOrEqual(t, framework.FetchInt(vend, "QueryCacheSize"), 3*cachedPlanSize)
+	assert.GreaterOrEqual(t, framework.FetchInt(vend, "QueryPlanCacheSize"), 3*cachedPlanSize)
 }
 
 func TestMaxResultSize(t *testing.T) {

go/vt/vttablet/endtoend/misc_test.go

@@ -198,7 +198,7 @@ func TestTrailingComment(t *testing.T) {
 		}
 		v2 := framework.Server.QueryPlanCacheLen()
 		if v2 != v1+1 {
-			t.Errorf("QueryCacheLength(%s): %d, want %d", query, v2, v1+1)
+			t.Errorf("QueryPlanCacheLength(%s): %d, want %d", query, v2, v1+1)
 		}
 	}
 }

go/vt/vttablet/tabletserver/debugenv.go

@@ -152,7 +152,8 @@ func debugEnvHandler(tsv *TabletServer, w http.ResponseWriter, r *http.Request)
 	vars = addVar(vars, "PoolSize", tsv.PoolSize)
 	vars = addVar(vars, "StreamPoolSize", tsv.StreamPoolSize)
 	vars = addVar(vars, "TxPoolSize", tsv.TxPoolSize)
-	vars = addVar(vars, "QueryCacheCapacity", tsv.QueryPlanCacheCap)
+	vars = addVar(vars, "QueryCacheCapacity", tsv.QueryPlanCacheCap) // QueryCacheCapacity is deprecated in v21, it is replaced by QueryPlanCacheCapacity
+	vars = addVar(vars, "QueryPlanCacheCapacity", tsv.QueryPlanCacheCap)
 	vars = addVar(vars, "MaxResultSize", tsv.MaxResultSize)
 	vars = addVar(vars, "WarnResultSize", tsv.WarnResultSize)
 	vars = addVar(vars, "RowStreamerMaxInnoDBTrxHistLen", func() int64 { return tsv.Config().RowStreamer.MaxInnoDBTrxHistLen })

go/vt/vttablet/tabletserver/query_engine.go

@@ -188,7 +188,7 @@ type QueryEngine struct {
 	// stats
 	// Note: queryErrorCountsWithCode is similar to queryErrorCounts except it contains error code as an additional dimension
 	queryCounts, queryCountsWithTabletType, queryTimes, queryErrorCounts, queryErrorCountsWithCode, queryRowsAffected, queryRowsReturned, queryTextCharsProcessed *stats.CountersWithMultiLabels
-	queryCacheHits, queryCacheMisses                                                                                                                              *stats.CounterFunc
+	queryPlanCacheHits, queryPlanCacheMisses                                                                                                                      *stats.CounterFunc
 
 	// stats flags
 	enablePerWorkloadTableMetrics bool
@@ -269,22 +269,51 @@ func NewQueryEngine(env tabletenv.Env, se *schema.Engine) *QueryEngine {
 	env.Exporter().NewGaugeFunc("StreamBufferSize", "Query engine stream buffer size", qe.streamBufferSize.Load)
 	env.Exporter().NewCounterFunc("TableACLExemptCount", "Query engine table ACL exempt count", qe.tableaclExemptCount.Load)
 
-	env.Exporter().NewGaugeFunc("QueryCacheLength", "Query engine query cache length", func() int64 {
+	// QueryCacheLength is deprecated in v21 and will be removed in >v22. This metric is replaced by QueryPlanCacheLength.
+	env.Exporter().NewGaugeFunc("QueryCacheLength", "Query engine query plan cache length (deprecated: please use QueryPlanCacheLength)", func() int64 {
 		return int64(qe.plans.Len())
 	})
-	env.Exporter().NewGaugeFunc("QueryCacheSize", "Query engine query cache size", func() int64 {
+	env.Exporter().NewGaugeFunc("QueryPlanCacheLength", "Query engine query plan cache length", func() int64 {
+		return int64(qe.plans.Len())
+	})
+
+	// QueryCacheSize is deprecated in v21 and will be removed in >v22. This metric is replaced QueryPlanCacheSizeQueryPlanCacheLength.
+	env.Exporter().NewGaugeFunc("QueryCacheSize", "Query engine query plan cache size (deprecated: please use QueryPlanCacheSize)", func() int64 {
+		return int64(qe.plans.UsedCapacity())
+	})
+	env.Exporter().NewGaugeFunc("QueryPlanCacheSize", "Query engine query plan cache size", func() int64 {
 		return int64(qe.plans.UsedCapacity())
 	})
-	env.Exporter().NewGaugeFunc("QueryCacheCapacity", "Query engine query cache capacity", func() int64 {
+
+	// QueryCacheCapacity is deprecated in v21 and will be removed in >v22. This metric is replaced by QueryPlanCacheCapacity.
+	env.Exporter().NewGaugeFunc("QueryCacheCapacity", "Query engine query plan cache capacity (deprecated: please use QueryPlanCacheCapacity)", func() int64 {
+		return int64(qe.plans.MaxCapacity())
+	})
+	env.Exporter().NewGaugeFunc("QueryPlanCacheCapacity", "Query engine query plan cache capacity", func() int64 {
 		return int64(qe.plans.MaxCapacity())
 	})
-	env.Exporter().NewCounterFunc("QueryCacheEvictions", "Query engine query cache evictions", func() int64 {
+
+	// QueryCacheEvictions is deprecated in v21 and will be removed in >v22. This metric is replaced by QueryPlanCacheEvictions.
+	env.Exporter().NewCounterFunc("QueryCacheEvictions", "Query engine query plan cache evictions (deprecated: please use QueryPlanCacheEvictions)", func() int64 {
 		return qe.plans.Metrics.Evicted()
 	})
-	qe.queryCacheHits = env.Exporter().NewCounterFunc("QueryCacheHits", "Query engine query cache hits", func() int64 {
+	env.Exporter().NewCounterFunc("QueryPlanCacheEvictions", "Query engine query plan cache evictions", func() int64 {
+		return qe.plans.Metrics.Evicted()
+	})
+
+	// QueryCacheHits is deprecated in v21 and will be removed in >v22. This metric is replaced by QueryPlanCacheHits.
+	_ = env.Exporter().NewCounterFunc("QueryCacheHits", "Query engine query plan cache hits (deprecated: please use QueryPlanCacheHits)", func() int64 {
+		return qe.plans.Metrics.Hits()
+	})
+	qe.queryPlanCacheHits = env.Exporter().NewCounterFunc("QueryPlanCacheHits", "Query engine query plan cache hits", func() int64 {
 		return qe.plans.Metrics.Hits()
 	})
-	qe.queryCacheMisses = env.Exporter().NewCounterFunc("QueryCacheMisses", "Query engine query cache misses", func() int64 {
+
+	// QueryCacheMisses is deprecated in v21 and will be removed in >v22. This metric is replaced by QueryPlanCacheMisses.
+	_ = env.Exporter().NewCounterFunc("QueryCacheMisses", "Query engine query plan cache misses (deprecated: please use QueryPlanCacheMisses)", func() int64 {
+		return qe.plans.Metrics.Misses()
+	})
+	qe.queryPlanCacheMisses = env.Exporter().NewCounterFunc("QueryPlanCacheMisses", "Query engine query plan cache misses", func() int64 {
 		return qe.plans.Metrics.Misses()
 	})
 

go/vt/vttablet/tabletserver/query_engine_test.go

@@ -197,26 +197,26 @@ func TestQueryPlanCache(t *testing.T) {
 	ctx := context.Background()
 	logStats := tabletenv.NewLogStats(ctx, "GetPlanStats")
 
-	initialHits := qe.queryCacheHits.Get()
-	initialMisses := qe.queryCacheMisses.Get()
+	initialHits := qe.queryPlanCacheHits.Get()
+	initialMisses := qe.queryPlanCacheMisses.Get()
 
 	firstPlan, err := qe.GetPlan(ctx, logStats, firstQuery, false)
 	require.NoError(t, err)
 	require.NotNil(t, firstPlan, "plan should not be nil")
 
 	assertPlanCacheSize(t, qe, 1)
 
-	require.Equal(t, int64(0), qe.queryCacheHits.Get()-initialHits)
-	require.Equal(t, int64(1), qe.queryCacheMisses.Get()-initialMisses)
+	require.Equal(t, int64(0), qe.queryPlanCacheHits.Get()-initialHits)
+	require.Equal(t, int64(1), qe.queryPlanCacheMisses.Get()-initialMisses)
 
 	secondPlan, err := qe.GetPlan(ctx, logStats, firstQuery, false)
 	require.NoError(t, err)
 	require.NotNil(t, secondPlan, "plan should not be nil")
 
 	assertPlanCacheSize(t, qe, 1)
 
-	require.Equal(t, int64(1), qe.queryCacheHits.Get()-initialHits)
-	require.Equal(t, int64(1), qe.queryCacheMisses.Get()-initialMisses)
+	require.Equal(t, int64(1), qe.queryPlanCacheHits.Get()-initialHits)
+	require.Equal(t, int64(1), qe.queryPlanCacheMisses.Get()-initialMisses)
 
 	qe.ClearQueryPlanCache()
 }