incr command in Memcached is used to atomically increment a numeric value stored in a key. It's most commonly used for counters or similar use cases where concurrent increments could occur, and atomicity is required to prevent possible race conditions.
Here we'll make use of the
EnyimMemcachedCore library which is a popular choice for Memcached in .NET Core:
In this example, we first connect our client to a locally running Memcached server. We then set an initial value for our key 'counter'. Finally, we use the
Increment function to increase the value of our counter by one.
If you want to increment with a default value (used when the key does not exist yet):
In the second example, we attempt to increment the value of 'counter' even if it doesn't exist yet. If it doesn't exist, Memcached will initialize it with our specified default value (10 in this case) before performing the increment.
incr, always ensure the value you're incrementing is a numerical type. Memcached's
incroperation works with numeric values only.
incrcommand for counters or similar constructs but not for general arithmetic operations on arbitrary numbers.
incroperation only works with numeric values and it won't create a new key if one doesn't already exist (unless providing a default value).
incrwhenever multiple threads or processes could be modifying a value simultaneously to prevent race conditions.
Q: What happens if I try to increment a key that doesn't exist? A: By default, Memcached will return an error. However, the C# client allows you to specify a default value that will be used if the key doesn't exist yet.
Q: What will happen if I try to increment a value that is not a number?
A: The increment operation will fail. Memcached's
incr operation can only work with numeric values.