Describe auto-incrementing primary keys

Author: kriszyp

docs/developers/applications/defining-schemas.md

@@ -165,7 +165,7 @@ The field directives can be used for information about each attribute in table t
 
 #### `@primaryKey`
 
-The `@primaryKey` directive specifies that an attribute is the primary key for a table. These must be unique and when records are created, this will be auto-generated with a UUID if no primary key is provided.
+The `@primaryKey` directive specifies that an attribute is the primary key for a table. These must be unique and when records are created, this will be auto-generated if no primary key is provided. When a primary key is auto-generated, it will be a UUID (as a string) if the primary key type is `String` or `ID`. If the primary key type is `Int`, `Long`, or `Any`, then the primary key will be an auto-incremented number. Using numeric primary keys is more efficient than using UUIDs. Note that if the type is `Int`, the primary key will be limited to 32-bit, which can be limiting and problematic for large tables. It is recommended that if you will be relying on auto-generated keys, that you use a primary key type of `Long` or `Any` (the latter will allow you to also use strings as primary keys). 
 
 #### `@indexed`
 

docs/developers/operations-api/nosql-operations.md

@@ -2,7 +2,7 @@
 
 ## Insert
 
-Adds one or more rows of data to a database table. Primary keys of the inserted JSON record may be supplied on insert. If a primary key is not provided, then a GUID will be generated for each record.
+Adds one or more rows of data to a database table. Primary keys of the inserted JSON record may be supplied on insert. If a primary key is not provided, then a GUID or incremented number (depending on type) will be generated for each record.
 
 * operation _(required)_ - must always be `insert`
 * database _(optional)_ - database where the table you are inserting records into lives. The default is `data`

docs/technical-details/release-notes/4.tucker/4.4.0.md

@@ -42,6 +42,10 @@ On startup, HarperDB will now print out an informative status of all running ser
 
 Resource methods can now return a `Response` object (or an object with `headers` and `status`) to allow for more control over the response.
 
+### Auto-incrementing Primary Keys
+
+Primary keys can now be auto-incrementing, allowing for automatic generation of numeric primary keys on insert/creation. Primary keys defined with `ID` or `String` will continue to use GUIDs for auto-assigned primary keys, which occurs on insert or creation if the primary key is not provided. However, for keys that are defined as `Any`, `Int`, or `Long`, the primary key will be assigned using auto-incrementation. This is significantly more efficient than GUIDs since the key only requires 8 bytes of storage instead of 31 bytes, and doesn't require random number generation.
+
 #### Developer/Production Mode for Configuration
 
 When using interactive installation (when configuration is not provided through arguments or env vars), HarperDB now provides an option for developer or production mode with a set of default configuration for each mode better suited for developer or production environments.