Move the constant into knobs

Author: Xin Dong

src/Constants.cpp

@@ -76,6 +76,5 @@ const char* MT_TIME_INSERT_LATENCY_US = "dl_insert_latency_useconds";
 const char* MT_HIST_INSERT_SZ = "dl_insert_size_bytes";
 const char* MT_HIST_TR_PER_REQUEST = "dl_tr_per_request";
 const char* MT_RATE_IDX_REBUILD = "dl_index_rebuild_rate";
-const uint64_t SLOW_QUERY_THRESHOLD_MICRO_SECONDS = 10000;
 
 } // namespace DocLayerConstants

src/Constants.h

@@ -89,8 +89,6 @@ extern const char* MT_TIME_INSERT_LATENCY_US;
 extern const char* MT_HIST_INSERT_SZ;
 extern const char* MT_HIST_TR_PER_REQUEST;
 extern const char* MT_RATE_IDX_REBUILD;
-// TODO: make this part of the knob/options instead of constants?
-extern const uint64_t SLOW_QUERY_THRESHOLD_MICRO_SECONDS;
 
 } // namespace DocLayerConstants
 

src/ExtMsg.actor.cpp

@@ -517,9 +517,9 @@ ACTOR static Future<Void> doRun(Reference<ExtMsgQuery> query, Reference<ExtConne
 	uint64_t queryLatencyMicroSeconds = (timer_int() - startTime) / 1000;
 	DocumentLayer::metricReporter->captureTime(DocLayerConstants::MT_TIME_QUERY_LATENCY_US, queryLatencyMicroSeconds);
 
-	if (slowQueryLogging && queryLatencyMicroSeconds >= DocLayerConstants::SLOW_QUERY_THRESHOLD_MICRO_SECONDS) {
+	if (slowQueryLogging && queryLatencyMicroSeconds >= DOCLAYER_KNOBS->SLOW_QUERY_THRESHOLD_MICRO_SECONDS) {
 		TraceEvent(SevWarn, "SlowQuery")
-		    .detail("ThresholdMicroSeconds", DocLayerConstants::SLOW_QUERY_THRESHOLD_MICRO_SECONDS)
+		    .detail("ThresholdMicroSeconds", DOCLAYER_KNOBS->SLOW_QUERY_THRESHOLD_MICRO_SECONDS)
 		    .detail("DurationMicroSeconds", queryLatencyMicroSeconds)
 		    .detail("Query", query->toString());
 	}

src/Knobs.cpp

@@ -44,6 +44,7 @@ DocLayerKnobs::DocLayerKnobs(bool enable) {
 	init(MAX_RETURNABLE_DATA_SIZE, (1 << 20) * 16);
 	init(CURSOR_EXPIRY, 60 * 10); /* seconds */
 	init(DEFAULT_RETURNABLE_DATA_SIZE, (1 << 20) * 4);
+	init(SLOW_QUERY_THRESHOLD_MICRO_SECONDS, 10 * 1000 * 1000);
 }
 
 bson::BSONObj DocLayerKnobs::dumpKnobs() const {

src/Knobs.h

@@ -37,6 +37,7 @@ class DocLayerKnobs : public Knobs {
 	int MAX_RETURNABLE_DATA_SIZE;
 	int CURSOR_EXPIRY;
 	int DEFAULT_RETURNABLE_DATA_SIZE;
+	int SLOW_QUERY_THRESHOLD_MICRO_SECONDS;
 
 	explicit DocLayerKnobs(bool randomize = false);