TidesDB Admintool Reference

If you want to download the source of this document, you can find it here.

Overview

Admintool is a command-line utility for managing and inspecting TidesDB databases. It provides interactive and non-interactive modes for database operations, diagnostics, and maintenance.

Installation

Build from source:

mkdir build && cd build
cmake ..
make

Usage

admintool [options]

Options

Option	Description
`-h, --help`	Show help message
`-v, --version`	Show TidesDB version
`-d, --directory <path>`	Open database at path on startup
`-c, --command <cmd>`	Execute command and exit

Examples

# Interactive mode
admintool

# Open database on startup
admintool -d ./mydb

# Execute single command
admintool -d ./mydb -c "cf-list"

Database Operations

open

Open or create a database.

open <path> [options]

Options

Option	Description
`--unified`	Enable unified memtable mode
`--unified-buffer-size <n>`	Unified memtable write buffer size (bytes)
`--unified-sync <mode>`	Unified WAL sync mode (`none`\|`interval`\|`full`)
`--unified-sync-interval <us>`	Unified WAL sync interval (microseconds)
`--cache-size <n>`	Block cache size (bytes, 0 to disable)
`--max-open-sstables <n>`	Max cached SSTable structures
`--flush-threads <n>`	Flush thread pool size
`--compaction-threads <n>`	Compaction thread pool size
`--max-memory <n>`	Global memory limit (bytes, 0 = auto)

Examples

admintool> open ./mydb
Opened database at './mydb'

admintool> open ./mydb --unified
Opened database at './mydb' (unified memtable)

admintool> open ./mydb --unified --cache-size 134217728 --flush-threads 4
Opened database at './mydb' (unified memtable)

close

Close the current database.

close

info

Show database information including column families, cache stats, and mode.

info

Output includes

Database path
Column family list
Block cache statistics (entries, size, hits, misses, hit rate, partitions)
Unified memtable status (enabled/disabled)
Object store status and connector type (if active)
Replica mode status (if active)

backup

Create a backup of the open database.

backup <destination_path>

version

Show TidesDB version.

version

Column Family Operations

cf-list

List all column families.

cf-list

cf-create

Create a new column family.

cf-create <name> [options]

Options

Option	Description
`--btree`	Use B+tree format for klog (faster point lookups)
`--compression <algo>`	Compression algorithm: `none`\|`lz4`\|`lz4-fast`\|`zstd`\|`snappy`
`--bloom-fpr <rate>`	Bloom filter false positive rate (e.g., `0.01` for 1%)
`--no-bloom`	Disable bloom filters
`--sync <mode>`	WAL sync mode: `none`\|`interval`\|`full`
`--sync-interval <us>`	Sync interval in microseconds (for `interval` mode)
`--comparator <name>`	Key comparator: `memcmp`\|`lexicographic`\|`uint64`\|`int64`\|`reverse`\|`case_insensitive`
`--write-buffer-size <n>`	Memtable flush threshold (bytes)
`--klog-value-threshold <n>`	Value size threshold for vlog storage (bytes)
`--block-index-prefix-len <n>`	Block index prefix length
`--index-sample-ratio <n>`	Block index sample ratio
`--no-block-indexes`	Disable block indexes
`--skip-list-max-level <n>`	Skip list max level
`--skip-list-probability <f>`	Skip list probability
`--isolation <level>`	Default transaction isolation level
`--min-disk-space <n>`	Minimum required disk space (bytes)
`--l1-trigger <n>`	L1 file count compaction trigger
`--l0-stall <n>`	L0 queue stall threshold
`--level-size-ratio <n>`	Level size multiplier
`--min-levels <n>`	Minimum LSM levels

Examples

cf-create users
cf-create cache --btree
cf-create logs --compression zstd --sync full --bloom-fpr 0.001
cf-create events --comparator reverse --write-buffer-size 134217728

Compression algorithms

Algorithm	Description	Use case
`none`	No compression	Pre-compressed data, max write throughput
`lz4`	LZ4 standard (default)	General purpose, balanced
`lz4-fast`	LZ4 fast mode	Write-heavy, speed over ratio
`zstd`	Zstandard	Best compression ratio, storage-constrained
`snappy`	Snappy	Legacy compatibility (not available on SunOS)

Sync modes

Mode	Description	Use case
`none`	No explicit sync, relies on OS page cache	Caches, temporary data
`interval`	Periodic background syncing	Most production workloads
`full`	Fsync on every write	Financial transactions, audit logs

Built-in comparators

Name	Description
`memcmp`	Binary byte-by-byte comparison (default)
`lexicographic`	Null-terminated string comparison
`uint64`	Unsigned 64-bit integer comparison
`int64`	Signed 64-bit integer comparison
`reverse`	Reverse binary comparison (descending order)
`case_insensitive`	Case-insensitive ASCII comparison

cf-drop

Drop a column family.

cf-drop <name>

cf-rename

Rename a column family.

cf-rename <old_name> <new_name>

cf-clone

Clone a column family. Creates a complete copy of an existing column family with a new name, including all data.

cf-clone <source_name> <destination_name>

Behavior

Flushes the source column family’s memtable to ensure all data is on disk
Waits for any in-progress flush or compaction to complete
Copies all SSTable files (.klog and .vlog) to the new directory
Copies manifest and configuration files
The clone is completely independent; modifications to one do not affect the other

Use cases

Testing with a copy of production data
Creating a snapshot before experimental changes
Data migration before configuration changes

Example

admintool(./mydb)> cf-clone users users_backup
Cloned column family 'users' to 'users_backup'

cf-stats

Show column family statistics and configuration.

cf-stats <name>

Output includes

Memtable size, levels, total keys
Data size, avg key/value sizes
Read amplification, cache hit rate
Full configuration (compression, bloom filter, sync mode, etc.)
Per-level SSTable counts and sizes
B+tree statistics (if enabled)

cf-status

Show flush/compaction status.

cf-status <name>

cf-update

Update runtime-safe configuration settings for a column family. Changes apply to new operations only; existing SSTables and memtables retain their original settings.

cf-update <name> [options]

Options

All options from cf-create are supported except --btree and --comparator (these cannot be changed after creation). Additionally:

Option	Description
`--persist`	Save changes to disk (default)
`--no-persist`	Apply changes in-memory only

Updatable settings

--compression · Compression for new SSTables (existing SSTables retain their original compression)
--bloom-fpr, --no-bloom · Bloom filter settings for new SSTables
--sync, --sync-interval · Durability mode (also updates the active WAL immediately)
--write-buffer-size · Memtable flush threshold
--klog-value-threshold · Value log threshold for new writes
--block-index-prefix-len, --index-sample-ratio, --no-block-indexes · Block index settings for new SSTables
--skip-list-max-level, --skip-list-probability · Skip list settings for new memtables
--isolation · Default transaction isolation level
--level-size-ratio, --min-levels · LSM level sizing
--l1-trigger, --l0-stall · Compaction and backpressure thresholds
--min-disk-space · Minimum disk space required

Non-updatable settings

--comparator · Cannot change sort order after creation (would corrupt key ordering)
--btree · Cannot change klog format after creation (existing SSTables use the original format)

Examples

admintool(./mydb)> cf-update users --compression zstd --bloom-fpr 0.001
Configuration updated for 'users' (persisted to disk)

admintool(./mydb)> cf-update cache --write-buffer-size 268435456 --no-persist
Configuration updated for 'cache' (in-memory only)

Key-Value Operations

put

Insert or update a key-value pair.

put <cf> <key> <value> [--ttl <seconds>]

--ttl <seconds> · Set time-to-live in seconds from now. The key expires after the specified duration. If omitted, the key does not expire.

Examples

admintool(./mydb)> put users user:1 "John Doe"
OK

admintool(./mydb)> put sessions sess:abc "token123" --ttl 3600
OK (expires at 1711584000)

get

Retrieve a value by key.

get <cf> <key>

delete

Delete a key.

delete <cf> <key>

scan

Scan all keys in a column family.

scan <cf> [limit]

Default limit: 100

range

Scan keys within a range.

range <cf> <start_key> <end_key> [limit]

prefix

Scan keys with a prefix.

prefix <cf> <prefix> [limit]

SSTable Inspection

sstable-list

List all SSTables in a column family.

sstable-list <cf>

sstable-info

Show SSTable file information.

sstable-info <klog_path>

sstable-dump

Dump SSTable entries (keys and values).

sstable-dump <klog_path> [limit]

Default limit: 1000

sstable-dump-full

Dump SSTable entries with vlog value resolution.

sstable-dump-full <klog_path> [vlog_path] [limit]

sstable-stats

Show SSTable statistics.

sstable-stats <klog_path>

sstable-keys

List only keys from an SSTable.

sstable-keys <klog_path> [limit]

sstable-checksum

Verify SSTable block checksums.

sstable-checksum <klog_path>

bloom-stats

Show bloom filter statistics for an SSTable.

bloom-stats <klog_path>

WAL Inspection

wal-list

List WAL files in a column family.

wal-list <cf>

wal-info

Show WAL file information.

wal-info <wal_path>

wal-dump

Dump WAL entries. Automatically detects per-CF and unified WAL formats.

wal-dump <wal_path> [limit]

Default limit: 1000

For unified WAL files (created when using --unified mode), each entry is prefixed with [CF:<index>] showing which column family the entry belongs to. Unified WAL blocks can contain multiple entries per block.

Example (per-CF WAL)

admintool(./mydb)> wal-dump ./mydb/users/wal_000001.log 5
WAL Entries (limit: 5):
1) [PUT] seq=1 key="user:1" value="John Doe"
2) [PUT] [TTL:1711584000] seq=2 key="sess:abc" value="token123"
3) [DELETE] seq=3 key="user:2"

(3 WAL entries dumped)

Example (unified WAL)

admintool(./mydb)> wal-dump ./mydb/uwal_000001.log 5
WAL Entries (limit: 5):
1) [CF:0] [PUT] seq=10 key="user:1" value="Alice"
2) [CF:1] [PUT] seq=10 key="order:1" value="item_A"
3) [CF:0] [PUT] seq=11 key="user:2" value="Bob"

(3 WAL entries dumped)

wal-verify

Verify WAL integrity. Automatically detects per-CF and unified WAL formats and reports the format type.

wal-verify <wal_path>

Example

admintool(./mydb)> wal-verify ./mydb/users/wal_000001.log
Verifying WAL: ./mydb/users/wal_000001.log
  File Size: 4096 bytes
  Format: Per-CF WAL
  Valid Entries: 42
  Corrupted Entries: 0
  Sequence Range: 1 - 42
  Last Valid Position: 3840
  Status: OK

wal-checksum

Verify WAL block checksums.

wal-checksum <wal_path>

Maintenance

level-info

Show per-level SSTable details.

level-info <cf>

verify

Verify column family integrity.

verify <cf>

compact

Trigger compaction on a column family.

compact <cf>

flush

Flush memtable to disk.

flush <cf>

purge-cf

Purge a single column family. Forces a synchronous flush and aggressive compaction, blocking until all I/O is complete.

purge-cf <name>

Behavior

Waits for any in-progress flush to complete
Force-flushes the active memtable (even if below threshold)
Waits for flush I/O to fully complete
Waits for any in-progress compaction to complete
Triggers synchronous compaction inline (bypasses the compaction queue)
Waits for any queued compaction to drain

Use cases

Before backup or checkpoint to ensure all data is on disk and compacted
After bulk deletes to reclaim space immediately
Manual maintenance during a maintenance window
Pre-shutdown to ensure all pending work is complete

Example

admintool(./mydb)> purge-cf users
Purging column family 'users' (synchronous flush + compaction)...
Purge completed for 'users'

purge

Purge all column families. Forces a synchronous flush and aggressive compaction for every column family, then drains both the global flush and compaction queues.

purge

Behavior

Calls purge-cf on each column family
Drains the global flush queue
Drains the global compaction queue

Example

admintool(./mydb)> purge
Purging all column families (synchronous flush + compaction)...
Database purge completed.

sync-wal

Force an immediate fsync of the active write-ahead log for a column family. Useful for explicit durability control when using TDB_SYNC_NONE or TDB_SYNC_INTERVAL modes.

sync-wal <cf>

Use cases

Application-controlled durability at specific points
Pre-checkpoint to ensure all buffered WAL data is on disk
Graceful shutdown to flush WAL buffers
Force durability for specific high-value writes

Example

admintool(./mydb)> sync-wal users
WAL synced for 'users'

checkpoint

Create a lightweight, near-instant snapshot of the open database using hard links instead of copying SSTable data.

checkpoint <destination_path>

Behavior

Requires destination to be a non-existent or empty directory
Flushes active memtables so all data is in SSTables
Halts compactions to ensure a consistent view
Hard links all SSTable files (.klog and .vlog) into the checkpoint directory
Copies small metadata files (manifest, config)
Resumes compactions
Falls back to file copy if hard linking fails (e.g., cross-filesystem)

Checkpoint vs Backup

	`backup`	`checkpoint`
Speed	Copies every SSTable byte-by-byte	Near-instant (hard links)
Disk usage	Full independent copy	No extra disk until compaction removes old SSTables
Portability	Can be moved to another filesystem or machine	Same filesystem only
Use case	Archival, disaster recovery	Fast local snapshots, point-in-time reads

Example

admintool(./mydb)> checkpoint ./mydb_checkpoint
Creating checkpoint at './mydb_checkpoint'...
Checkpoint completed successfully.

db-stats

Show aggregate statistics across the entire database instance.

db-stats

Output includes

Column family count
System total and available memory
Resolved memory limit and memory pressure level (normal/elevated/high/critical)
Global sequence number
Flush queue size and pending count
Compaction queue size
Total SSTables, total data size
Open SSTable handles
In-flight transaction memory
Immutable memtable count and total memtable bytes
Unified memtable section (if enabled): memtable bytes, immutable count, flushing status, WAL generation, next CF index
Object store section (if enabled): connector type, replica mode, local cache usage, upload stats

Example

admintool(./mydb)> db-stats
Database Statistics:
  Path: ./mydb
  Column Families: 2
  Total Memory: 16777216000 bytes (16000.00 MB)
  Available Memory: 8388608000 bytes (8000.00 MB)
  Resolved Memory Limit: 8388608000 bytes (8000.00 MB)
  Memory Pressure Level: 0 (normal)
  Global Sequence: 1042
  Flush Queue Size: 0
  Flush Pending Count: 0
  Compaction Queue Size: 0
  Total SSTables: 5
  Total Data Size: 1048576 bytes (1.00 MB)
  Open SSTable Handles: 5
  In-Flight Txn Memory: 0 bytes
  Immutable Memtables: 0
  Total Memtable Bytes: 2048
  Unified Memtable:
    Enabled: yes
    Memtable Bytes: 4096
    Immutable Count: 0
    Is Flushing: no
    Next CF Index: 3
    WAL Generation: 7

Example with object store

admintool(./mydb)> db-stats
...
  Object Store:
    Enabled: yes
    Connector: s3
    Replica Mode: no
    Local Cache: 524288000 / 1073741824 bytes (42 files)
    Last Uploaded Generation: 6
    Upload Queue Depth: 0
    Total Uploads: 156
    Total Upload Failures: 0

cache-stats

Show detailed block cache statistics.

cache-stats

Output includes

Whether cache is enabled
Total cached entries and size (bytes and MB)
Cache hits and misses
Hit rate percentage
Number of cache partitions

Example

admintool(./mydb)> cache-stats
Block Cache Statistics:
  Enabled: yes
  Entries: 128
  Size: 8388608 bytes (8.00 MB)
  Hits: 5432
  Misses: 312
  Hit Rate: 94.57%
  Partitions: 8

range-cost

Estimate the computational cost of iterating between two keys in a column family. Uses only in-memory metadata with no disk I/O. The returned value is a relative scalar, meaningful only for comparison with other range-cost results.

range-cost <cf> <key_a> <key_b>

Example

admintool(./mydb)> range-cost users user:0000 user:0999
Range cost for 'users' [user:0000 .. user:0999]: 42.500000

admintool(./mydb)> range-cost users user:1000 user:1099
Range cost for 'users' [user:1000 .. user:1099]: 8.250000

Use cases

Query planning: compare candidate key ranges to find the cheapest to scan
Load balancing: distribute range scan work across threads
Monitoring: track data distribution changes across key ranges

promote

Promote a read-only replica to primary. This performs a final MANIFEST sync and WAL replay, creates a local WAL for crash recovery, and atomically switches to primary mode.

promote

Example

admintool(./mydb_replica)> promote
Promoted to primary successfully.

Behavior

Only valid when the database is in replica mode
Performs a final MANIFEST sync and WAL replay
Atomically transitions from replica to primary mode
After promotion, writes are accepted normally
Returns an error if the database is already a primary

Interactive Mode

When run without -c, admintool enters interactive mode with a prompt:

admintool>

When a database is open:

admintool(./mydb)>

Type help for available commands, quit or exit to leave.

Examples

Create database and column family

admintool> open ./mydb
Opened database at './mydb'
admintool(./mydb)> cf-create users
Created column family 'users'

Create database with unified memtable

admintool> open ./mydb --unified --cache-size 134217728
Opened database at './mydb' (unified memtable)

Create column family with custom settings

admintool(./mydb)> cf-create logs --compression zstd --sync interval --sync-interval 100000 --bloom-fpr 0.001
Created column family 'logs'

Update column family configuration at runtime

admintool(./mydb)> cf-update users --compression zstd --write-buffer-size 268435456
Configuration updated for 'users' (persisted to disk)

Insert and retrieve data

admintool(./mydb)> put users user:1 "John Doe"
OK
admintool(./mydb)> get users user:1
John Doe

Insert with TTL

admintool(./mydb)> put sessions sess:abc "token123" --ttl 3600
OK (expires at 1711584000)

Inspect column family

admintool(./mydb)> cf-stats users
Column Family: users
  Memtable Size: 1024 bytes
  Levels: 5
  Total Keys: 1
  ...

Scan with prefix

admintool(./mydb)> prefix users user: 10
1) "user:1" -> "John Doe"
(1 entries with prefix)

Compare range scan costs

admintool(./mydb)> range-cost users user:0000 user:0999
Range cost for 'users' [user:0000 .. user:0999]: 42.500000
admintool(./mydb)> range-cost users user:1000 user:1099
Range cost for 'users' [user:1000 .. user:1099]: 8.250000

Verify integrity

admintool(./mydb)> verify users
Verifying column family 'users'...
Verification passed.