You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: sysvar.go
    path of file: ./repos/tidb/pkg/sessionctx/variable
    
    the code of the file until where you have to start completion: // Copyright 2015 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the
    
func GlobalSystemVariableInitialValue(varName, varVal string) string {
	switch varName {
	case TiDBEnableAsyncCommit, TiDBEnable1PC:
		if config.GetGlobalConfig().Store == "tikv" {
			varVal = On
		}
	case TiDBMemOOMAction:
		if intest.InTest {
			varVal = OOMActionLog
		}
	case TiDBEnableAutoAnalyze:
		if intest.InTest {
			varVal = Off
		}
	// For the following sysvars, we change the default
	// FOR NEW INSTALLS ONLY. In most cases you don't want to do this.
	// It is better to change the value in the Sysvar struct, so that
	// all installs will have the same value.
	case TiDBRowFormatVersion:
		varVal = strconv.Itoa(DefTiDBRowFormatV2)
	case TiDBTxnAssertionLevel:
		varVal = AssertionFastStr
	case TiDBEnableMutationChecker:
		varVal = On
	case TiDBPessimisticTransactionFairLocking:
		varVal = On
	}
	return varVal
}