Prepending in Memcached with Golang (Detailed Guide w/ Code Examples)
Prepending data is often used when you want to add information at the beginning of existing data in a cache. For instance, if you have a string value and later decide to include some metadata at the start of this string without disturbing the already stored value.
The gomemcache/memcache package provides the Prepend method for prepending data to an existing memcache item.
In this sample code, we set the value "world" for key "foo". Then we prepend "Hello, " to the existing value. Finally, we get the value for the key "foo" which now returns "Hello, world".
Always check for errors after performing operations like Set or Prepend.
Consider the maximum size limit for a value. As per Memcached protocol, the value should not exceed 1MB including the data being prepended.
Not checking if the key already exists before prepending. The Prepend operation will fail if the key does not exist.
Ignoring concurrency issues. Multiple clients can prepend data, which could result in unexpected order of data.
Q: Can I prepend to non-string values?
A: Yes, but be mindful that Memcached operates on byte arrays, so it's up to your application to interpret these bytes. If you're dealing with complex data types, consider serialization or a different method of composition.