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Configuration Options

TangoDB uses an immutable builder pattern through io.tango.api.TangoConfig to customize engine behavior, memory sizing, disk directories, and background compaction tasks.

Configuration Properties​

ParameterTypeDefaultDescription
sstableDirectoryPathPath.of("data")Directory path where written SSTable data files and index metadata are persisted.
memTableSizelong67,108,864 (64 MiB)Maximum capacity in bytes of an active MemTable. Once reached, the table freezes and triggers asynchronous disk flush.
arenaBlockSizelong65,536 (64 KiB)Memory block allocation size used by ArenaAllocator for off-heap native memory segment allocation.
flushQueueSizeint8Bounded size of the asynchronous flush queue for background SSTable flushing tasks.
enableCompactionbooleantrueEnables or disables background SSTable merging and tombstone garbage collection.

Example Builder Usages​

Standard Production Setup​

import io.tango.api.TangoConfig;
import java.nio.file.Path;

TangoConfig config = TangoConfig.builder()
        .sstableDirectory(Path.of("/var/lib/tangodb/data"))
        .memTableSize(128L * 1024 * 1024) // 128 MiB MemTable
        .arenaBlockSize(128L * 1024)       // 128 KiB Block Size
        .flushQueueSize(16)
        .build();

Fast In-Memory Testing Setup​

For small-scale benchmarks or unit tests, setting a lower memTableSize triggers frequent background flushes:

TangoConfig testConfig = TangoConfig.builder()
        .sstableDirectory(Path.of("target/test-data"))
        .memTableSize(64L * 1024) // 64 KiB MemTable for quick flushes
        .arenaBlockSize(4L * 1024)
        .disableCompaction()      // Disable background compaction during specific tests
        .build();

Validation & Safety Rules​

When TangoConfig.builder().build() is invoked, the following invariant checks are strictly enforced:

  1. memTableSize must be positive: memTableSize > 0
  2. arenaBlockSize must be positive: arenaBlockSize > 0
  3. flushQueueSize must be positive: flushQueueSize > 0
  4. memTableSize >= arenaBlockSize: The total MemTable capacity cannot be smaller than an individual native allocation block.