refactor: remove outdated query modifiers (#311)

Author: fanyang01

backend/request_modifier.go

@@ -1,34 +1,10 @@
 package backend
 
-import "regexp"
-
 // RequestModifier is a function type that transforms a query string
 type RequestModifier func(string, *[]ResultModifier) string
 
-// Precompile regex for performance
-var autoIncrementRegex = regexp.MustCompile(`(?i)AUTO_INCREMENT=\d+`)
-var showSlaveStatusRegex = regexp.MustCompile(`(?i)^show\s+slave\s+status\s*;?$`)
-
 // default request modifier list
-var defaultRequestModifiers = []RequestModifier{
-	replaceAutoIncrement,
-	replaceShowSlaveStatus,
-}
-
-func replaceAutoIncrement(query string, modifiers *[]ResultModifier) string {
-	if autoIncrementRegex.MatchString(query) {
-		query = autoIncrementRegex.ReplaceAllString(query, "")
-	}
-	return query
-}
-
-func replaceShowSlaveStatus(query string, modifiers *[]ResultModifier) string {
-	if showSlaveStatusRegex.MatchString(query) {
-		*modifiers = append(*modifiers, replaceShowSlaveStatusFieldNames)
-		query = showSlaveStatusRegex.ReplaceAllString(query, "SHOW REPLICA STATUS;")
-	}
-	return query
-}
+var defaultRequestModifiers = []RequestModifier{}
 
 // applyRequestModifiers applies request modifiers to a query
 func applyRequestModifiers(query string, requestModifiers []RequestModifier) (string, []ResultModifier) {

backend/result_modifier.go

@@ -1,36 +1,8 @@
 package backend
 
 import (
-	"regexp"
-
 	"github.com/dolthub/vitess/go/sqltypes"
 )
 
-// ResultModifier is a function type that transforms a Result
+// ResultModifier transforms a Result.
 type ResultModifier func(*sqltypes.Result) *sqltypes.Result
-
-var (
-	replicaRegex = regexp.MustCompile(`^Replica_`)
-	sourceRegex  = regexp.MustCompile(`Source`)
-)
-
-// replaceFieldNames modifies field names to maintain compatibility with older MySQL clients
-// by replacing "Replica_" with "Slave_" and "Source" with "Master"
-func replaceShowSlaveStatusFieldNames(result *sqltypes.Result) *sqltypes.Result {
-	if result == nil || result.Fields == nil {
-		return result
-	}
-
-	for i, field := range result.Fields {
-		name := field.Name
-		// Replace any "Replica_" with "Slave_"
-		if replicaRegex.MatchString(name) {
-			result.Fields[i].Name = replicaRegex.ReplaceAllString(name, "Slave_")
-		}
-		// Replace any "Source" with "Master"
-		if sourceRegex.MatchString(name) {
-			result.Fields[i].Name = sourceRegex.ReplaceAllString(name, "Master")
-		}
-	}
-	return result
-}