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Concept Directory Structure

Maruf Çetin

Concept: Directory Structure and Layout

Turkce Dokumantasyon | English Documentation

Category: Core Concepts & Architecture
Subsystem: Storage & Filesystem Architecture (AmberDB::Base)
Entry Type: Directory Hierarchy & Placement Guide

1. Definition and Overview

The AmberDB Directory Structure defines a clean, deterministic physical hierarchy that cleanly segregates schemas, authoritative master data, derived secondary indexes, transaction journals, RAM-disk mount points, and disaster recovery archives.

All database files reside under a single root database directory (conventionally named dbstore/). AmberDB automatically inspects and scaffolds this hierarchy upon instantiation.

Standard AmberDB Directory Hierarchy (dbstore/)

 dbstore/
 ├── schema/                      ← Schema Definitions
 │   ├── catalog.dbase            ← Database group configuration
 │   └── catalog_products.table   ← Table schema definition
 ├── tables/                      ← Master Data & Derived Indexes
 │   ├── catalog_products.db      ← Berkeley DB primary table
 │   ├── catalog_products.del     ← Soft-deleted recycle bin archive
 │   ├── catalog_products.aut     ← User modification audit ledger
 │   ├── catalog_products.cnt     ← High-concurrency hit counter store
 │   ├── catalog_products.inx     ← 8-byte packed primary ID index
 │   ├── catalog_products_1.fld   ← Inverted exact-match index
 │   ├── catalog_products_2.src   ← Full-text phonetic search index
 │   ├── catalog_products_3.fac   ← Columnar facet bitset index
 │   ├── catalog_products_4.srt   ← Monotonic binary sorted index
 │   └── catalog_products_1.unq   ← Bidirectional dictionary and uniqueness index
 ├── backup/                      ← Continuous WAL & .amberdb Archives
 │   └── 2026/
 │       ├── 2026-09-01.csv       ← Continuous daily audit stream (Pillar 1)
 │       └── full_backup.amberdb  ← Compressed backup archive (Pillar 2)
 ├── cache/                       ← RAM-Disk Shared Memory (tmpfs / ImDisk)
 ├── buffer/                      ← Transient Disk Staging Files (.tmp)
 └── txn/                         ← Active Transaction Undo Journals (.txn)

2. Subdirectory Functional Reference

Directory Type Purpose
schema/ Persistent Houses table schemas (.table) and database group configurations (.dbase).
tables/ Persistent Primary master data (.db, .del, .aut, .cnt, .unq) and derived reconstructible indexes (.inx, .fld, .src, .fac, .srt, .slg).
backup/ Persistent / Archive Year-partitioned folders (backup/YYYY/) holding daily append-only CSV WAL streams and native .amberdb archives.
cache/ Shared Memory Mount target for OS RAM-disks (tmpfs / ImDisk). High-frequency table mirrors operate here.
buffer/ Transient (Staging) Stores staging buffer files (.tmp) during buffer_write pipelines.
txn/ Transient (ACID) Stores active transaction rollback journals (.txn). Removed upon successful commit.

3. Configuring and Mutating Directory Paths

The root database directory path is set during instantiation using path => { dbase_dir => ... } or modified dynamically via $adb->set_datadir():

use AmberDB;

# 1. Initialize instance with custom database root
my $adb = AmberDB->new(
    path => { dbase_dir => "/var/data/ecommerce_dbstore" }
);

# 2. Change storage path dynamically at runtime
$adb->set_datadir("/mnt/ssd_storage/dbstore");

4. Security and Filesystem Best Practices

[!WARNING]
Web Security (Preventing Direct HTTP Access):
Ensure the database root (dbstore/) is located strictly outside the web server's public document root (htdocs, public_html, www). If it must reside within the document tree, configure web server rules or .htaccess to deny all direct HTTP access unconditionally.

[!TIP]
Cross-Platform Path Compatibility:
Use lowercase ASCII alphanumeric characters, underscores (_), and hyphens (-) for folder names to ensure seamless portability across Linux, Windows, and macOS.

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