Following my last blog post on Unclogging Queue Entries.

We know that we need to trigger delta update by creating V3 job to push the data into Delta Queue.
For note, these process are running on ECC-Side.
There are 3 different update method for this delta:
1. Direct Delta
• In this update method, data is directly transferred to Delta Queue and application tables at same time,
with every document posting
• Here, 1 document = 1 LUW (Logistic Unit of Work)
• Suitable for a small datasource type

2. Queue Delta
• In this update method, the records are first sent to ‘Extraction Queue’ using V1 update
Note: This ‘Extraction Queue’ entries recorded in serialize way. That’s why the queue delta are suitable for serialization document number.
• From ‘Extraction Queue’, we need to send the records to ‘Delta Queue’ using collection
run
• In this update method, we can collect up to 10,000 documents in one LUW

3. Unserialized V3 Update
• Here, the extracted data of an application is written to update tables using V3 update
• We need to send the data from Update Tables (SM13) to Delta Queue (RSA7) using Collection Run
• In this, serialization of documents is not guaranteed

Image above showing the difference of three update methods.
> Direct Delta VS Queue & V3 Unserialize
Data from transaction updated directly into Delta Queue using V1.
Meanwhile, Queue & V3 Unserialize have temporary table( Extraction & Update Table).
> Queue VS V3 Unserialize
Extraction suitable for serialization & V3 Unserialize are not.
Queue Delta check with LBWQ.
V3 Unserialize check with SM13.

source: http://scn.sap.com/docs/DOC-33012