perf: optimize lookupCommand

command.go

@@ -1,7 +1,9 @@
 package main
 
 import (
+ "fmt"
  "strconv"
+ "strings"
 
  "github.com/xgzlucario/rotom/internal/dict"
  "github.com/xgzlucario/rotom/internal/hash"
@@ -16,8 +18,8 @@ type Command struct {
  // handler is this command real database handler function.
  handler func(writer *RESPWriter, args []RESP)
 
- // arity represents the minimal number of arguments that command accepts.
- arity int
+ // minArgsNum represents the minimal number of arguments that command accepts.
+ minArgsNum int
 
  // persist indicates whether this command needs to be persisted.
  // effective when `appendonly` is true.
@@ -49,33 +51,22 @@ var cmdTable []*Command = []*Command{
  {"mset", todoCommand, 0, false},
  {"zpopmin", todoCommand, 0, false},
  {"xadd", todoCommand, 0, false},
+ // TODO: distribution
+ {"sync", todoCommand, 0, false},
+ {"log", todoCommand, 0, false},
 }
 
-func lookupCommand(command string) *Command {
+func lookupCommand(name string) (*Command, error) {
  for _, c := range cmdTable {
- if equalCommand(command, c.name) {
- return c
+ if len(name) == len(c.name) && strings.EqualFold(name, c.name) {
+ return c, nil
  }
  }
- return nil
-}
-
-func equalCommand(str, lowerText string) bool {
- if len(str) != len(lowerText) {
- return false
- }
- const s = 'a' - 'A'
- for i, lt := range lowerText {
- delta := lt - rune(str[i])
- if delta != 0 && delta != s {
- return false
- }
- }
- return true
+ return nil, fmt.Errorf("%w '%s'", errUnknownCommand, name)
 }
 
 func (cmd *Command) processCommand(writer *RESPWriter, args []RESP) {
- if len(args) < cmd.arity {
+ if len(args) < cmd.minArgsNum {
  writer.WriteError(errInvalidArguments)
  return
  }

resp.go

@@ -2,7 +2,6 @@ package main
 
 import (
  "bytes"
- "fmt"
  "io"
  "slices"
  "strconv"
@@ -97,7 +96,7 @@ func (r *RESPReader) ReadNextCommand(argsBuf []RESP) (args []RESP, err error) {
  // command_inline format
  before, after, ok := cutByCRLF(r.b)
  if !ok {
- return nil, fmt.Errorf("%w '%s'", errUnknownCommand, r.b)
+ return nil, errInvalidArguments
  }
  args = append(args, before)
  r.b = after

rotom.go

@@ -1,7 +1,6 @@
 package main
 
 import (
- "fmt"
  "io"
  "runtime"
  "runtime/debug"
@@ -67,10 +66,10 @@ func InitDB(config *Config) (err error) {
  // Load the initial data into memory by processing each stored command.
  emptyWriter := NewWriter(WRITE_BUF_SIZE)
  return db.aof.Read(func(args []RESP) {
- command := args[0].ToString()
+ command := args[0].ToStringUnsafe()
 
- cmd := lookupCommand(command)
- if cmd != nil {
+ cmd, err := lookupCommand(command)
+ if err == nil {
  cmd.processCommand(emptyWriter, args[1:])
  emptyWriter.Reset()
  }
@@ -154,23 +153,24 @@ func ProcessQueryBuf(client *Client) {
  command := args[0].ToStringUnsafe()
  args = args[1:]
 
- cmd := lookupCommand(command)
- if cmd != nil {
- cmd.processCommand(client.replyWriter, args)
+ cmd, err := lookupCommand(command)
+ if err != nil {
+ client.replyWriter.WriteError(err)
+ log.Error().Msg(err.Error())
 
- if server.outOfMemory {
+ } else {
+ // reject write request when OOM
+ if cmd.persist && server.outOfMemory {
  client.replyWriter.WriteError(errOOM)
  goto WRITE
  }
 
- if server.config.AppendOnly && cmd.persist {
+ cmd.processCommand(client.replyWriter, args)
+
+ // write aof file
+ if cmd.persist && server.config.AppendOnly {
  db.aof.Write(queryBuf)
  }
-
- } else {
- err := fmt.Errorf("%w '%s'", errUnknownCommand, command)
- client.replyWriter.WriteError(err)
- log.Error().Msg(err.Error())
  }
  }