# Technical Document Extraction: Log Session Windowing Diagram
## 1. Overview
This image is a technical diagram illustrating the process of partitioning a continuous **System Log** into discrete **Log Sequences** based on specific identifiers (Block IDs) using a "Session window" mechanism. The diagram uses color-coding to track specific data blocks across different log views.
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## 2. Component Isolation
### Region A: Source (System Log)
Located on the left side of the diagram, this represents the raw, interleaved stream of log entries.
**Table: System Log Content**
| Line # | Log Entry Text |
| :--- | :--- |
| 1 | Receiving block <span style="color:red">blk_-5632101276183739500</span> src: /10.251.27.63:36433 dest: /10.251.27.63:50010 |
| 2 | BLOCK* NameSystem.allocateBlock: /user/root/randtxt4/_temporary/task_200811101024/part-00999. <span style="color:red">blk_-5632101276183739500</span> |
| 3 | Receiving block <span style="color:blue">blk_-4506306395053060141</span> src: /10.251.193.175:40709 dest: /10.251.193.175:50010 |
| 4 | PacketResponder 0 for block <span style="color:red">blk_-5632101276183739500</span> terminating |
| ... | ... |
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### Region B: Process (Session Window)
A central horizontal arrow points from the System Log to the Log Sequences.
* **Label:** "Session window"
* **Function:** This represents the logic that filters and groups the interleaved log entries into separate sequences based on the unique Block ID.
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### Region C: Output (Log Sequences)
Located on the right side, consisting of stacked windows representing filtered views of the original log.
#### **Log Sequence #1 (For blk_-5632101276183739500)**
This sequence extracts only the entries related to the red-colored Block ID.
| Line # | Log Entry Text |
| :--- | :--- |
| 1 | Receiving block <span style="color:red">blk_-5632101276183739500</span> src: /10.251.27.63:36433 dest: /10.251.27.63:50010 |
| 2 | BLOCK* NameSystem.allocateBlock: /user/root/randtxt4/_temporary/task_200811101024/part-00999. <span style="color:red">blk_-5632101276183739500</span> |
| 3 | PacketResponder 0 for block <span style="color:red">blk_-5632101276183739500</span> terminating |
| ... | ... |
#### **Log Sequence #2 (For blk_-4506306395053060141)**
This sequence (partially obscured in the background) extracts entries related to the blue-colored Block ID.
| Line # | Log Entry Text |
| :--- | :--- |
| 1 | Receiving block <span style="color:blue">blk_-4506306395053060141</span> src: /10.251.193.175:40709 dest: /... |
*Note: There is a vertical ellipsis (⋮) above the sequences, indicating that multiple such sequences are generated for different block IDs.*
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## 3. Data Mapping & Trend Verification
### Color Coding Logic
* **Red Text:** Refers to `blk_-5632101276183739500`. In the System Log, these appear at lines 1, 2, and 4. In Log Sequence #1, they are consolidated into a continuous sequence (lines 1, 2, and 3).
* **Blue Text:** Refers to `blk_-4506306395053060141`. In the System Log, this appears at line 3. In the output, it is moved to the first line of Log Sequence #2.
### Flow Analysis
1. **Input:** A single stream where events for different processes (blocks) are mixed chronologically.
2. **Transformation:** The "Session window" identifies the unique identifier in each line.
3. **Output:** The stream is demultiplexed. Each unique identifier gets its own dedicated "Log Sequence" window, maintaining the relative chronological order of events for that specific identifier while removing unrelated noise.
