Allow to pass max_results_row, extremes and result_overflow_mode params

cache/cache.go

@@ -80,14 +80,24 @@ type Key struct {
 	// Namespace is an optional cache namespace.
 	Namespace string
 
+	// MaxResultRows must contain `max_result_rows` query arg
+	MaxResultRows string
+
+	// Extremes must contain `extremes` query arg
+	Extremes string
+
+	// ResultOverflowMode must contain `result_overflow_mode` query arg
+	ResultOverflowMode string
+
 	// UserParamsHash must contain hashed value of users params
 	UserParamsHash uint32
 }
 
 // String returns string representation of the key.
 func (k *Key) String() string {
-	s := fmt.Sprintf("V%d; Query=%q; AcceptEncoding=%q; DefaultFormat=%q; Database=%q; Compress=%q; EnableHTTPCompression=%q; Namespace=%q; UserParams=%d",
-		cacheVersion, k.Query, k.AcceptEncoding, k.DefaultFormat, k.Database, k.Compress, k.EnableHTTPCompression, k.Namespace, k.UserParamsHash)
+	s := fmt.Sprintf("V%d; Query=%q; AcceptEncoding=%q; DefaultFormat=%q; Database=%q; Compress=%q; EnableHTTPCompression=%q; Namespace=%q; MaxResultRows=%q; Extremes=%q; ResultOverflowMode=%q; UserParams=%d",
+		cacheVersion, k.Query, k.AcceptEncoding, k.DefaultFormat, k.Database, k.Compress, k.EnableHTTPCompression, k.Namespace,
+		k.MaxResultRows, k.Extremes, k.ResultOverflowMode, k.UserParamsHash)
 	h := sha256.Sum256([]byte(s))
 
 	// The first 16 bytes of the hash should be enough

cache/cache_test.go

@@ -48,22 +48,22 @@ func TestKeyString(t *testing.T) {
 			key: &Key{
 				Query: []byte("SELECT 1 FROM system.numbers LIMIT 10"),
 			},
-			expected: "b84443ea3b7651f8eed84ad70cc17d55",
+			expected: "bebe3382e36ffdeea479b45d827b208a",
 		},
 		{
 			key: &Key{
 				Query:          []byte("SELECT 1 FROM system.numbers LIMIT 10"),
 				AcceptEncoding: "gzip",
 			},
-			expected: "baece3cc15d1aa1516e2729409ece703",
+			expected: "498c1af30fb94280fd7c7225c0c8fb39",
 		},
 		{
 			key: &Key{
 				Query:          []byte("SELECT 1 FROM system.numbers LIMIT 10"),
 				AcceptEncoding: "gzip",
 				DefaultFormat:  "JSON",
 			},
-			expected: "c238bde938f93419e93b5b7b0341f1ef",
+			expected: "720292aa0647cc5e53e0b6e6033eef34",
 		},
 		{
 			key: &Key{
@@ -72,7 +72,7 @@ func TestKeyString(t *testing.T) {
 				DefaultFormat:  "JSON",
 				Database:       "foobar",
 			},
-			expected: "e55de3951f08688a34e589caaeed437f",
+			expected: "5c6a70736d71e570faca739c4557780c",
 		},
 		{
 			key: &Key{
@@ -82,7 +82,7 @@ func TestKeyString(t *testing.T) {
 				Database:       "foobar",
 				Namespace:      "ns123",
 			},
-			expected: "a8676b65119982a1fa135005e0583a07",
+			expected: "08b4baf6825e53bbd18136a88abda4f8",
 		},
 		{
 			key: &Key{
@@ -93,7 +93,7 @@ func TestKeyString(t *testing.T) {
 				Compress:       "1",
 				Namespace:      "ns123",
 			},
-			expected: "9a2ad211524d5c8983d43784fd59677d",
+			expected: "0e043f23ccd1b9039b33623b3b7c114a",
 		},
 	}
 

proxy.go

@@ -264,6 +264,9 @@ func (rp *reverseProxy) serveFromCache(s *scope, srw *statResponseWriter, req *h
 		Compress:              origParams.Get("compress"),
 		EnableHTTPCompression: origParams.Get("enable_http_compression"),
 		Namespace:             origParams.Get("cache_namespace"),
+		Extremes:              origParams.Get("extremes"),
+		MaxResultRows:         origParams.Get("max_result_rows"),
+		ResultOverflowMode:    origParams.Get("result_overflow_mode"),
 		UserParamsHash:        paramsHash,
 	}
 

scope.go

@@ -299,6 +299,12 @@ var allowedParams = []string{
 	"decompress",
 	// compress the result if the client over HTTP said that it understands data compressed by gzip or deflate.
 	"enable_http_compression",
+	// limit on the number of rows in the result
+	"max_result_rows",
+	// whether to count extreme values
+	"extremes",
+	// what to do if the volume of the result exceeds one of the limits
+	"result_overflow_mode",
 }
 
 // This regexp must match params needed to describe a way to use external data