diff --git a/README.md b/README.md
index 6150eb5..ae1af94 100644
--- a/README.md
+++ b/README.md
@@ -168,6 +168,7 @@ There are around 6 billion unique external backlinks per month in the common cra
 - 4GB of RAM is the minimum requirement. Requires 1.5GB of RAM per every next thread for parsing.
 - Minimum 50GB of free disk for every segment parsed at the same time.
 - MongoDB require minimum 2GB of disc space for every segment. 200MB of ram for every imported segment is optimal.
+- lzop installed on the system.
 
 ## Alpha Version Disclaimer
 This is an alpha version of GlobalLinks and is subject to changes. The software is provided "as is", without warranty of any kind.
diff --git a/cmd/importer/main.go b/cmd/importer/main.go
index 04a2bf5..ceb114e 100644
--- a/cmd/importer/main.go
+++ b/cmd/importer/main.go
@@ -19,12 +19,15 @@ import (
 
 	"github.com/kris-dev-hub/globallinks/pkg/commoncrawl"
 	"github.com/kris-dev-hub/globallinks/pkg/fileutils"
+
+	_ "net/http/pprof"
 )
 
 const (
 	savePageData     = false // collect and parse page data
 	lowDiscSpaceMode = true  // encrypt tmp files to save disc space during sorting, requires lzop installed
 	healthCheckMode  = true  // enable health check api to monitor application on port 3005: http://localhost:3005/health
+	pprofMode        = false // enable pprof api to monitor application on port 6060: http://localhost:6060/debug/pprof/
 )
 
 const (
@@ -54,6 +57,13 @@ type FileLinkCompacted struct {
 }
 
 func main() {
+
+	if pprofMode == true {
+		go func() {
+			log.Println(http.ListenAndServe("localhost:6060", nil))
+		}()
+	}
+
 	var err error
 	var archiveName string
 	var segmentsToImport []int
@@ -513,24 +523,32 @@ func compactSegmentData(segment commoncrawl.WatSegment, dataDir commoncrawl.Data
 				return fmt.Errorf("could not delete WAT processed files: %v", err)
 			}
 		}
-		err = fileutils.DeleteDirectoryIfEmpty(dataDir.TmpDir + "/" + segment.Segment)
-		if err != nil {
-			return fmt.Errorf("could not delete tmp directories: %v", err)
-		}
 
-		err = aggressiveCompacting(linkSegmentSorted, linkSegmentCompacted)
-		if err != nil {
-			return fmt.Errorf("could not compact file: %v", err)
-		}
-		err = os.Remove(linkSegmentSorted)
-		if err != nil {
-			return fmt.Errorf("could not delete file: %v", err)
-		}
+		if fileutils.FileExists(linkSegmentSorted) {
 
-		// save info that segment was finished
-		err = commoncrawl.UpdateSegmentImportEnd(segmentList, segment.Segment)
-		if err != nil {
-			return fmt.Errorf("%v", err)
+			err = fileutils.DeleteDirectoryIfEmpty(dataDir.TmpDir + "/" + segment.Segment)
+			if err != nil {
+				return fmt.Errorf("could not delete tmp directories: %v", err)
+			}
+
+			err = aggressiveCompacting(linkSegmentSorted, linkSegmentCompacted)
+			if err != nil {
+				return fmt.Errorf("could not compact file: %v", err)
+			}
+			err = os.Remove(linkSegmentSorted)
+			if err != nil {
+				return fmt.Errorf("could not delete file: %v", err)
+			}
+
+			// save info that segment was finished
+			err = commoncrawl.UpdateSegmentImportEnd(segmentList, segment.Segment)
+			if err != nil {
+				return fmt.Errorf("%v", err)
+			}
+		} else {
+			if err != nil {
+				return fmt.Errorf("can't find sorted file!\n")
+			}
 		}
 	}
 
diff --git a/pkg/commoncrawl/wat.go b/pkg/commoncrawl/wat.go
index 2223b7e..74dca33 100644
--- a/pkg/commoncrawl/wat.go
+++ b/pkg/commoncrawl/wat.go
@@ -122,6 +122,8 @@ type DataDir struct {
 // saves around 1s per 1M lines on one i5-9300H core
 var ipRegex = regexp.MustCompile(`^(?:25[0-5]|2[0-4]\d|1\d\d|[1-9]\d|\d)(?:\.(?:25[0-5]|2[0-4]\d|1\d\d|[1-9]\d|\d)){3}$`)
 
+var isValidDomainRegex = regexp.MustCompile(`^(?i)([a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?\.)+[a-z]{2,}$`)
+
 // initialize a map for fast lookups - it will be used to ignore certain domains and extensions
 var (
 	ignoreDomains      = map[string]bool{}
@@ -591,28 +593,8 @@ func verifyRecordQuality(record *URLRecord) bool {
 
 // validateHose - validate host for strange characters and no dots
 func validateHost(host string) bool {
-	if strings.Contains(host, "%") ||
-		strings.Contains(host, "[") ||
-		strings.Contains(host, "]") ||
-		strings.Contains(host, "=") ||
-		strings.Contains(host, "'") ||
-		strings.Contains(host, ":") ||
-		strings.Contains(host, "*") ||
-		strings.Contains(host, "(") ||
-		strings.Contains(host, ")") ||
-		strings.Contains(host, "<") ||
-		strings.Contains(host, ">") ||
-		strings.Contains(host, "&") ||
-		strings.Contains(host, "!") ||
-		strings.Contains(host, "+") ||
-		strings.Contains(host, "`") ||
-		strings.Contains(host, ",") ||
-		strings.Contains(host, "}") ||
-		strings.Contains(host, "{") ||
-		strings.Contains(host, "$") ||
-		strings.Contains(host, "\"") ||
-		strings.Contains(host, ":") ||
-		strings.Contains(host, ";") {
+
+	if strings.ContainsAny(host, "%[]=':*()<>!&+,}{}$\";`") {
 		return false
 	}
 
@@ -628,12 +610,14 @@ func validateHost(host string) bool {
 	return true
 }
 
-// final verification of domain
+// IsValidDomain - final verification of domain
 func IsValidDomain(domain string) bool {
 	// Regular expression to match valid domain characters and rules
 	// This regex does not cover all possible TLDs and might need modification for specific cases
-	re := regexp.MustCompile(`^(?i)([a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?\.)+[a-z]{2,}$`)
-	return re.MatchString(domain)
+	//	re := regexp.MustCompile(`^(?i)([a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?\.)+[a-z]{2,}$`)
+
+	// moving regex to global variable to make it faster - saved around 10% of time
+	return isValidDomainRegex.MatchString(domain)
 }
 
 // buildURLRecord - build url record from source url, check domain, path, query, etc.
@@ -651,13 +635,8 @@ func buildURLRecord(sourceURL string, urlRecord *URLRecord) bool {
 		return false
 	}
 
-	// ignore path with \n
-	if strings.Contains(parsedURL.Path, "\n") {
-		return false
-	}
-
-	// ignore path with | char
-	if strings.Contains(parsedURL.Path, "|") {
+	// ignore path with \n and | char
+	if strings.ContainsAny(parsedURL.Path, "\n|") {
 		return false
 	}