cmd_del.go

cmd_del.go - Overview

This file defines the DEL command, which deletes specified keys from the data store and returns the number of keys deleted.

Detailed Documentation

cDEL

var cDEL = &CommandMeta{
	Name:      "DEL",
	Syntax:    "DEL key [key ...]",
	HelpShort: "DEL deletes all the specified keys",
	HelpLong:  `DEL command deletes all the specified keys and returns the number of keys deleted on success.`,
	Examples: `
	localhost:7379> SET k1 v1
OK OK
	localhost:7379> SET k2 v2
OK OK
	localhost:7379> DEL k1 k2 k3
OK 2`,
	Eval:    evalDEL,
	Execute: executeDEL,
}

• Purpose: Defines the metadata for the DEL command, including its name, syntax, help messages, examples, and the functions to evaluate and execute the command.
• Fields:
  • Name: The name of the command ("DEL").
  • Syntax: The syntax of the command ("DEL key [key ...]").
  • HelpShort: A short description of the command.
  • HelpLong: A longer description of the command.
  • Examples: Example usage of the command.
  • Eval: The function to evaluate the command (evalDEL).
  • Execute: The function to execute the command (executeDEL).

evalDEL

func evalDEL(c *Cmd, s *dstore.Store) (*CmdRes, error) {
	if len(c.C.Args) < 1 {
		return cmdResNil, errors.ErrWrongArgumentCount("DEL")
	}

	var count int
	for _, key := range c.C.Args {
		if ok := s.Del(key); ok {
			count++
		}
	}

	return cmdResInt(int64(count)), nil
}

• Purpose: Evaluates the DEL command by deleting the specified keys from the provided data store.
• Parameters:
  • c (*Cmd): The command context, containing the arguments for the DEL command.
  • s (*dstore.Store): The data store instance to delete keys from.
• Returns:
  • *CmdRes: A command result containing the number of keys deleted.
  • error: An error if the number of arguments is incorrect.

executeDEL

func executeDEL(c *Cmd, sm *shardmanager.ShardManager) (*CmdRes, error) {
	if len(c.C.Args) < 1 {
		return cmdResNil, errors.ErrWrongArgumentCount("DEL")
	}

	var count int64
	for _, key := range c.C.Args {
		shard := sm.GetShardForKey(key)
		r, err := evalDEL(c, shard.Thread.Store())
		if err != nil {
			return nil, err
		}
		count += r.R.GetVInt()
	}
	return cmdResInt(count), nil
}

• Purpose: Executes the DEL command by deleting the specified keys across shards managed by the shard manager.
• Parameters:
  • c (*Cmd): The command context, containing the arguments for the DEL command.
  • sm (*shardmanager.ShardManager): The shard manager instance to retrieve shards from.
• Returns:
  • *CmdRes: A command result containing the total number of keys deleted across all shards.
  • error: An error if the number of arguments is incorrect or if an error occurs during the evaluation of the command on a shard.

Code Examples

None.

Getting Started Relevance