AIPersist Storage Engine

The AIPersist engine (aipersist) provides durable storage using B+ tree data structures with checkpoint-based persistence. Data is stored in partition files on disk with an in-memory page cache for fast access. This is the default storage engine.

Storage Architecture

Storage organization:

• Each partition stored in a separate file: table-{tableId}/part-{partitionId}.bin
• Delta files capture incremental changes between checkpoints
• B+ trees store version chains (row data), sorted indexes, hash indexes, and metadata
• Default page size: 16 KB

Checkpointing

Checkpointing flushes dirty pages from memory to partition files on disk. This process ensures durability and enables crash recovery.

Checkpoint configuration:

Property	Default	Description
intervalMillis	180000	Time between checkpoints (3 minutes)
intervalDeviationPercent	40	Random deviation to prevent synchronized checkpoints
checkpointThreads	-	Number of checkpoint writer threads
compactionThreads	-	Number of compaction threads

# Configure checkpoint interval to 2 minutes
node config update ignite.storage.engines.aipersist.checkpoint.intervalMillis=120000

Write Throttling

When the checkpoint buffer reaches two-thirds capacity (66.7%), write throttling activates to prevent buffer overflow.

Throttling behavior:

• Below 66%: Normal operation, no throttling
• 66% to 90%: Progressive throttling, checkpoint priority increases
• Above 90%: Heavy throttling, updates significantly delayed

Write throttling indicates either slow disk I/O or excessive write rate. Monitor throttling metrics to identify bottlenecks.

Profile Configuration

Property	Default	Description
engine	-	Must be "aipersist"
sizeBytes	Dynamic	Storage size. Defaults to max(256 MB, 20% of physical RAM)

Configuration Example

{
  "ignite": {
    "storage": {
      "profiles": [
        {
          "engine": "aipersist",
          "name": "persistent_profile",
          "sizeBytes": 2147483648
        }
      ]
    }
  }
}

# CLI equivalent
node config update "ignite.storage.profiles:{persistent_profile{engine:aipersist,sizeBytes:2147483648}}"

Usage

The default profile uses aipersist automatically. For custom profiles:

-- Create a zone with the persistent profile
CREATE ZONE transaction_zone
    WITH PARTITIONS=25, REPLICAS=3,
    STORAGE PROFILES ['persistent_profile'];

-- Create a durable table
CREATE TABLE orders (
    order_id BIGINT PRIMARY KEY,
    customer_id INT,
    total DECIMAL(15,2),
    created_at TIMESTAMP
) ZONE transaction_zone STORAGE PROFILE 'persistent_profile';