wrong config item description in config.toml.example

[qw4990]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do? If possible, provide a recipe for reproducing the error.
   Description of max-memory is wrong.

2. What did you expect to see?
   It may be Max memory size to use in plan cache.

3. What did you see instead?
   Max memory size to use in plan cache, 0 use the total usable memory in the machine.

4. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?
   The latest master branch.

[ghost]

This appears to be fixed in master:

nullnotnil@ubuntu:~/go/src/github.com/nullnotnil/tidb/config$ grep -RFi 'max-memory' config.toml.example 
nullnotnil@ubuntu:~/go/src/github.com/nullnotnil/tidb/config$ grep -RFi 'memory' config.toml.example 
# The maximum memory available for a single SQL statement. Default: 1GB
# Controls whether to enable the temporary storage for some operators when a single SQL statement exceeds the memory quota specified by mem-quota-query.
# Specifies the temporary storage path for some operators when a single SQL statement exceeds the memory quota specified by mem-quota-query.
# Specifies what operation TiDB performs when a single SQL statement exceeds the memory quota specified by mem-quota-query and cannot be spilled over to disk.
# Memory size quota for tidb server, 0 means unlimited
server-memory-quota = 0
# The max number of query feedback that cache in memory.
# the interval duration between two memory profile into global tracker
memory-guard-ratio = 0.1
# QueueSize controls how many spans the reporter can keep in memory before it starts dropping
# Whether to enable the copr cache. The copr cache saves the result from TiKV Coprocessor in the memory and
# max number of statements kept in memory.

I am going to go ahead and close this issue now. Please feel free to reopen if this is in error. Thanks!