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LmdbJava Benchmarks

Just want the latest results? View them here!

This is a JMH benchmark of open source, embedded, memory-mapped, key-value stores available from Java:

(**) does not support ordered keys, so iteration benchmarks not performed

The benchmark itself is adapted from LMDB's db_bench_mdb.cc, which in turn is adapted from LevelDB's benchmark.

The benchmark includes:

  • Writing data
  • Reading all data via each key
  • Reading all data via a reverse iterator
  • Reading all data via a forward iterator
  • Reading all data via a forward iterator and computing a CRC32 (via JDK API)
  • Reading all data via a forward iterator and computing a XXH64 (via extremely fastZero-Allocation-Hashing)

Byte arrays (byte[]) are always used for the keys and values, avoiding any serialization library overhead. For those libraries that support compression, it is disabled in the benchmark. In general any special library features that decrease latency (eg batch modes, disable auto-commit, disable journals, hint at expected data sizes etc) were used. While we have tried to be fair and consistent, some libraries offer non-obvious tuning settings or usage patterns that might further reduce their latency. We do not claim we have exhausted every tuning option every library exposes, but pull requests are most welcome.

Usage

This benchmark uses POSIX calls to accurately determine consumed disk space and only depends on Linux-specific native library wrappers where a range of such wrappers exists. Operation on non-Linux operating systems is unsupported.

  1. Clone this repository and mvn clean package
  2. Run the benchmark with java -jar target/benchmarks.jar

The benchmark offers many parameters, but to reduce execution time they default to a fast, mechanically-sympathetic workload (ie integer keys, sequential IO) that should fit in RAM. A default execution takes around 15 minutes on server-grade hardware (ie 2 x Intel Xeon E5-2667 v3 CPUs, 512 GB RAM etc).

You can append -h to the java -jar line for JMH help. For example, use:

  • -foe true to stop on any error (recommended)
  • -rf csv to emit a CSV results file (recommended)
  • -f 3 to run three forks for smaller error ranges (recommended)
  • -lp to list all available parameters
  • -p intKey=true,false to test both integer and string-based keys

The parameters (available from -lp) allow you to create workloads of different iteration counts (num), key sizes and layout (intKey), value sizes (valSize), mechanical sympathy (sequential, valRandom) and feature tuning (eg forceSafe, writeMap etc).

System.out will display the actual on-disk usage of each implementation as "Bytes" \t longVal \t benchId lines. This is not the "apparent" size (given sparse files are typical), but the actual on-disk space used. The underlying storage location defaults to the temporary file system. To force an alternate location, invoke Java with -Djava.io.tmpdir=/somewhere/you/like.

Support

Please open a GitHub issue if you have any questions.

Contributing

Contributions are welcome! Please see the LmdbJava project's Contributing Guidelines.

License

This project is licensed under the Apache License, Version 2.0.

About

Benchmark of open source, embedded, memory-mapped, key-value stores available from Java (JMH)

Resources

Readme
License

Contributing

Contributing
Activity

Stars

0 stars

Watchers

0 watching

Forks

0 forks
Report repository

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Packages

Contributors

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, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

Skip to content
BranchesTags
Repository files navigation
Maven BuildLicense
LmdbJava Benchmarks
Just want the latest results?
View them here!
This is a JMH benchmark
of open source, embedded, memory-mapped, key-value stores available from Java:
(**) does not support ordered keys, so iteration benchmarks not performed
The benchmark itself is adapted from LMDB's
db_bench_mdb.cc, which in
turn is adapted from
LevelDB's benchmark.
The benchmark includes:
  • Writing data
  • Reading all data via each key
  • Reading all data via a reverse iterator
  • Reading all data via a forward iterator
  • Reading all data via a forward iterator and computing a CRC32 (via JDK API)
  • Reading all data via a forward iterator and computing a XXH64
(via extremely fastZero-Allocation-Hashing)
Byte arrays (byte[]) are always used for the keys and values, avoiding any
serialization library overhead. For those libraries that support compression,
it is disabled in the benchmark. In general any special library features that
decrease latency (eg batch modes, disable auto-commit, disable journals,
hint at expected data sizes etc) were used. While we have tried to be fair and
consistent, some libraries offer non-obvious tuning settings or usage patterns
that might further reduce their latency. We do not claim we have exhausted
every tuning option every library exposes, but pull requests are most welcome.
Usage
This benchmark uses POSIX calls to accurately determine consumed disk space and
only depends on Linux-specific native library wrappers where a range of such
wrappers exists. Operation on non-Linux operating systems is unsupported.
  1. Clone this repository and mvn clean package
  2. Run the benchmark with java -jar target/benchmarks.jar
The benchmark offers many parameters, but to reduce execution time they default
to a fast, mechanically-sympathetic workload (ie integer keys, sequential IO)
that should fit in RAM. A default execution takes around 15 minutes on
server-grade hardware (ie 2 x Intel Xeon E5-2667 v3 CPUs, 512 GB RAM etc).
You can append -h to the java -jar line for JMH help. For example, use:
  • -foe true to stop on any error (recommended)
  • -rf csv to emit a CSV results file (recommended)
  • -f 3 to run three forks for smaller error ranges (recommended)
  • -lp to list all available parameters
  • -p intKey=true,false to test both integer and string-based keys
The parameters (available from -lp) allow you to create workloads of different
iteration counts (num), key sizes and layout (intKey), value sizes
(valSize), mechanical sympathy (sequential, valRandom) and feature tuning
(eg forceSafe, writeMap etc).
System.out will display the actual on-disk usage of each implementation as
"Bytes" \t longVal \t benchId lines. This is not the "apparent" size (given
sparse files are typical), but the actual on-disk space used. The underlying
storage location defaults to the temporary file system. To force an alternate
location, invoke Java with -Djava.io.tmpdir=/somewhere/you/like.
Support
Please open a GitHub issue
if you have any questions.
Contributing
Contributions are welcome! Please see the LmdbJava project's
Contributing Guidelines.
License
This project is licensed under the
Apache License, Version 2.0.
About
Benchmark of open source, embedded, memory-mapped, key-value stores available from Java (JMH)
Resources
Readme
License
Contributing
Contributing
Activity
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Packages
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
Maven BuildLicense
LmdbJava Benchmarks
Just want the latest results?
View them here!
This is a JMH benchmark
of open source, embedded, memory-mapped, key-value stores available from Java:
(**) does not support ordered keys, so iteration benchmarks not performed
The benchmark itself is adapted from LMDB's
db_bench_mdb.cc, which in
turn is adapted from
LevelDB's benchmark.
The benchmark includes:
  • Writing data
  • Reading all data via each key
  • Reading all data via a reverse iterator
  • Reading all data via a forward iterator
  • Reading all data via a forward iterator and computing a CRC32 (via JDK API)
  • Reading all data via a forward iterator and computing a XXH64
(via extremely fastZero-Allocation-Hashing)
Byte arrays (byte[]) are always used for the keys and values, avoiding any
serialization library overhead. For those libraries that support compression,
it is disabled in the benchmark. In general any special library features that
decrease latency (eg batch modes, disable auto-commit, disable journals,
hint at expected data sizes etc) were used. While we have tried to be fair and
consistent, some libraries offer non-obvious tuning settings or usage patterns
that might further reduce their latency. We do not claim we have exhausted
every tuning option every library exposes, but pull requests are most welcome.
Usage
This benchmark uses POSIX calls to accurately determine consumed disk space and
only depends on Linux-specific native library wrappers where a range of such
wrappers exists. Operation on non-Linux operating systems is unsupported.
  1. Clone this repository and mvn clean package
  2. Run the benchmark with java -jar target/benchmarks.jar
The benchmark offers many parameters, but to reduce execution time they default
to a fast, mechanically-sympathetic workload (ie integer keys, sequential IO)
that should fit in RAM. A default execution takes around 15 minutes on
server-grade hardware (ie 2 x Intel Xeon E5-2667 v3 CPUs, 512 GB RAM etc).
You can append -h to the java -jar line for JMH help. For example, use:
  • -foe true to stop on any error (recommended)
  • -rf csv to emit a CSV results file (recommended)
  • -f 3 to run three forks for smaller error ranges (recommended)
  • -lp to list all available parameters
  • -p intKey=true,false to test both integer and string-based keys
The parameters (available from -lp) allow you to create workloads of different
iteration counts (num), key sizes and layout (intKey), value sizes
(valSize), mechanical sympathy (sequential, valRandom) and feature tuning
(eg forceSafe, writeMap etc).
System.out will display the actual on-disk usage of each implementation as
"Bytes" \t longVal \t benchId lines. This is not the "apparent" size (given
sparse files are typical), but the actual on-disk space used. The underlying
storage location defaults to the temporary file system. To force an alternate
location, invoke Java with -Djava.io.tmpdir=/somewhere/you/like.
Support
Please open a GitHub issue
if you have any questions.
Contributing
Contributions are welcome! Please see the LmdbJava project's
Contributing Guidelines.
License
This project is licensed under the
Apache License, Version 2.0.
About
Benchmark of open source, embedded, memory-mapped, key-value stores available from Java (JMH)
Resources
Readme
License
Contributing
Contributing
Activity
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Packages
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
Maven BuildLicense
LmdbJava Benchmarks
Just want the latest results?
View them here!
This is a JMH benchmark
of open source, embedded, memory-mapped, key-value stores available from Java:
(**) does not support ordered keys, so iteration benchmarks not performed
The benchmark itself is adapted from LMDB's
db_bench_mdb.cc, which in
turn is adapted from
LevelDB's benchmark.
The benchmark includes:
  • Writing data
  • Reading all data via each key
  • Reading all data via a reverse iterator
  • Reading all data via a forward iterator
  • Reading all data via a forward iterator and computing a CRC32 (via JDK API)
  • Reading all data via a forward iterator and computing a XXH64
(via extremely fastZero-Allocation-Hashing)
Byte arrays (byte[]) are always used for the keys and values, avoiding any
serialization library overhead. For those libraries that support compression,
it is disabled in the benchmark. In general any special library features that
decrease latency (eg batch modes, disable auto-commit, disable journals,
hint at expected data sizes etc) were used. While we have tried to be fair and
consistent, some libraries offer non-obvious tuning settings or usage patterns
that might further reduce their latency. We do not claim we have exhausted
every tuning option every library exposes, but pull requests are most welcome.
Usage
This benchmark uses POSIX calls to accurately determine consumed disk space and
only depends on Linux-specific native library wrappers where a range of such
wrappers exists. Operation on non-Linux operating systems is unsupported.
  1. Clone this repository and mvn clean package
  2. Run the benchmark with java -jar target/benchmarks.jar
The benchmark offers many parameters, but to reduce execution time they default
to a fast, mechanically-sympathetic workload (ie integer keys, sequential IO)
that should fit in RAM. A default execution takes around 15 minutes on
server-grade hardware (ie 2 x Intel Xeon E5-2667 v3 CPUs, 512 GB RAM etc).
You can append -h to the java -jar line for JMH help. For example, use:
  • -foe true to stop on any error (recommended)
  • -rf csv to emit a CSV results file (recommended)
  • -f 3 to run three forks for smaller error ranges (recommended)
  • -lp to list all available parameters
  • -p intKey=true,false to test both integer and string-based keys
The parameters (available from -lp) allow you to create workloads of different
iteration counts (num), key sizes and layout (intKey), value sizes
(valSize), mechanical sympathy (sequential, valRandom) and feature tuning
(eg forceSafe, writeMap etc).
System.out will display the actual on-disk usage of each implementation as
"Bytes" \t longVal \t benchId lines. This is not the "apparent" size (given
sparse files are typical), but the actual on-disk space used. The underlying
storage location defaults to the temporary file system. To force an alternate
location, invoke Java with -Djava.io.tmpdir=/somewhere/you/like.
Support
Please open a GitHub issue
if you have any questions.
Contributing
Contributions are welcome! Please see the LmdbJava project's
Contributing Guidelines.
License
This project is licensed under the
Apache License, Version 2.0.
About
Benchmark of open source, embedded, memory-mapped, key-value stores available from Java (JMH)
Resources
Readme
License
Contributing
Contributing
Activity
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Packages
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
BranchesTags
Repository files navigation
Maven BuildLicense
LmdbJava Benchmarks
Just want the latest results?
View them here!
This is a JMH benchmark
of open source, embedded, memory-mapped, key-value stores available from Java:
(**) does not support ordered keys, so iteration benchmarks not performed
The benchmark itself is adapted from LMDB's
db_bench_mdb.cc, which in
turn is adapted from
LevelDB's benchmark.
The benchmark includes:
  • Writing data
  • Reading all data via each key
  • Reading all data via a reverse iterator
  • Reading all data via a forward iterator
  • Reading all data via a forward iterator and computing a CRC32 (via JDK API)
  • Reading all data via a forward iterator and computing a XXH64
(via extremely fastZero-Allocation-Hashing)
Byte arrays (byte[]) are always used for the keys and values, avoiding any
serialization library overhead. For those libraries that support compression,
it is disabled in the benchmark. In general any special library features that
decrease latency (eg batch modes, disable auto-commit, disable journals,
hint at expected data sizes etc) were used. While we have tried to be fair and
consistent, some libraries offer non-obvious tuning settings or usage patterns
that might further reduce their latency. We do not claim we have exhausted
every tuning option every library exposes, but pull requests are most welcome.
Usage
This benchmark uses POSIX calls to accurately determine consumed disk space and
only depends on Linux-specific native library wrappers where a range of such
wrappers exists. Operation on non-Linux operating systems is unsupported.
  1. Clone this repository and mvn clean package
  2. Run the benchmark with java -jar target/benchmarks.jar
The benchmark offers many parameters, but to reduce execution time they default
to a fast, mechanically-sympathetic workload (ie integer keys, sequential IO)
that should fit in RAM. A default execution takes around 15 minutes on
server-grade hardware (ie 2 x Intel Xeon E5-2667 v3 CPUs, 512 GB RAM etc).
You can append -h to the java -jar line for JMH help. For example, use:
  • -foe true to stop on any error (recommended)
  • -rf csv to emit a CSV results file (recommended)
  • -f 3 to run three forks for smaller error ranges (recommended)
  • -lp to list all available parameters
  • -p intKey=true,false to test both integer and string-based keys
The parameters (available from -lp) allow you to create workloads of different
iteration counts (num), key sizes and layout (intKey), value sizes
(valSize), mechanical sympathy (sequential, valRandom) and feature tuning
(eg forceSafe, writeMap etc).
System.out will display the actual on-disk usage of each implementation as
"Bytes" \t longVal \t benchId lines. This is not the "apparent" size (given
sparse files are typical), but the actual on-disk space used. The underlying
storage location defaults to the temporary file system. To force an alternate
location, invoke Java with -Djava.io.tmpdir=/somewhere/you/like.
Support
Please open a GitHub issue
if you have any questions.
Contributing
Contributions are welcome! Please see the LmdbJava project's
Contributing Guidelines.
License
This project is licensed under the
Apache License, Version 2.0.
About
Benchmark of open source, embedded, memory-mapped, key-value stores available from Java (JMH)
Resources
Readme
License
Contributing
Contributing
Activity
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Packages
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
Maven BuildLicense
LmdbJava Benchmarks
Just want the latest results?
View them here!
This is a JMH benchmark
of open source, embedded, memory-mapped, key-value stores available from Java:
(**) does not support ordered keys, so iteration benchmarks not performed
The benchmark itself is adapted from LMDB's
db_bench_mdb.cc, which in
turn is adapted from
LevelDB's benchmark.
The benchmark includes:
  • Writing data
  • Reading all data via each key
  • Reading all data via a reverse iterator
  • Reading all data via a forward iterator
  • Reading all data via a forward iterator and computing a CRC32 (via JDK API)
  • Reading all data via a forward iterator and computing a XXH64
(via extremely fastZero-Allocation-Hashing)
Byte arrays (byte[]) are always used for the keys and values, avoiding any
serialization library overhead. For those libraries that support compression,
it is disabled in the benchmark. In general any special library features that
decrease latency (eg batch modes, disable auto-commit, disable journals,
hint at expected data sizes etc) were used. While we have tried to be fair and
consistent, some libraries offer non-obvious tuning settings or usage patterns
that might further reduce their latency. We do not claim we have exhausted
every tuning option every library exposes, but pull requests are most welcome.
Usage
This benchmark uses POSIX calls to accurately determine consumed disk space and
only depends on Linux-specific native library wrappers where a range of such
wrappers exists. Operation on non-Linux operating systems is unsupported.
  1. Clone this repository and mvn clean package
  2. Run the benchmark with java -jar target/benchmarks.jar
The benchmark offers many parameters, but to reduce execution time they default
to a fast, mechanically-sympathetic workload (ie integer keys, sequential IO)
that should fit in RAM. A default execution takes around 15 minutes on
server-grade hardware (ie 2 x Intel Xeon E5-2667 v3 CPUs, 512 GB RAM etc).
You can append -h to the java -jar line for JMH help. For example, use:
  • -foe true to stop on any error (recommended)
  • -rf csv to emit a CSV results file (recommended)
  • -f 3 to run three forks for smaller error ranges (recommended)
  • -lp to list all available parameters
  • -p intKey=true,false to test both integer and string-based keys
The parameters (available from -lp) allow you to create workloads of different
iteration counts (num), key sizes and layout (intKey), value sizes
(valSize), mechanical sympathy (sequential, valRandom) and feature tuning
(eg forceSafe, writeMap etc).
System.out will display the actual on-disk usage of each implementation as
"Bytes" \t longVal \t benchId lines. This is not the "apparent" size (given
sparse files are typical), but the actual on-disk space used. The underlying
storage location defaults to the temporary file system. To force an alternate
location, invoke Java with -Djava.io.tmpdir=/somewhere/you/like.
Support
Please open a GitHub issue
if you have any questions.
Contributing
Contributions are welcome! Please see the LmdbJava project's
Contributing Guidelines.
License
This project is licensed under the
Apache License, Version 2.0.
About
Benchmark of open source, embedded, memory-mapped, key-value stores available from Java (JMH)
Resources
Readme
License
Contributing
Contributing
Activity
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Packages
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
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Repository files navigation
Maven BuildLicense
LmdbJava Benchmarks
Just want the latest results?
View them here!
This is a JMH benchmark
of open source, embedded, memory-mapped, key-value stores available from Java:
(**) does not support ordered keys, so iteration benchmarks not performed
The benchmark itself is adapted from LMDB's
db_bench_mdb.cc, which in
turn is adapted from
LevelDB's benchmark.
The benchmark includes:
  • Writing data
  • Reading all data via each key
  • Reading all data via a reverse iterator
  • Reading all data via a forward iterator
  • Reading all data via a forward iterator and computing a CRC32 (via JDK API)
  • Reading all data via a forward iterator and computing a XXH64
(via extremely fastZero-Allocation-Hashing)
Byte arrays (byte[]) are always used for the keys and values, avoiding any
serialization library overhead. For those libraries that support compression,
it is disabled in the benchmark. In general any special library features that
decrease latency (eg batch modes, disable auto-commit, disable journals,
hint at expected data sizes etc) were used. While we have tried to be fair and
consistent, some libraries offer non-obvious tuning settings or usage patterns
that might further reduce their latency. We do not claim we have exhausted
every tuning option every library exposes, but pull requests are most welcome.
Usage
This benchmark uses POSIX calls to accurately determine consumed disk space and
only depends on Linux-specific native library wrappers where a range of such
wrappers exists. Operation on non-Linux operating systems is unsupported.
  1. Clone this repository and mvn clean package
  2. Run the benchmark with java -jar target/benchmarks.jar
The benchmark offers many parameters, but to reduce execution time they default
to a fast, mechanically-sympathetic workload (ie integer keys, sequential IO)
that should fit in RAM. A default execution takes around 15 minutes on
server-grade hardware (ie 2 x Intel Xeon E5-2667 v3 CPUs, 512 GB RAM etc).
You can append -h to the java -jar line for JMH help. For example, use:
  • -foe true to stop on any error (recommended)
  • -rf csv to emit a CSV results file (recommended)
  • -f 3 to run three forks for smaller error ranges (recommended)
  • -lp to list all available parameters
  • -p intKey=true,false to test both integer and string-based keys
The parameters (available from -lp) allow you to create workloads of different
iteration counts (num), key sizes and layout (intKey), value sizes
(valSize), mechanical sympathy (sequential, valRandom) and feature tuning
(eg forceSafe, writeMap etc).
System.out will display the actual on-disk usage of each implementation as
"Bytes" \t longVal \t benchId lines. This is not the "apparent" size (given
sparse files are typical), but the actual on-disk space used. The underlying
storage location defaults to the temporary file system. To force an alternate
location, invoke Java with -Djava.io.tmpdir=/somewhere/you/like.
Support
Please open a GitHub issue
if you have any questions.
Contributing
Contributions are welcome! Please see the LmdbJava project's
Contributing Guidelines.
License
This project is licensed under the
Apache License, Version 2.0.
About
Benchmark of open source, embedded, memory-mapped, key-value stores available from Java (JMH)
Resources
Readme
License
Contributing
Contributing
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0 forks
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

Skip to content
BranchesTags
Repository files navigation
Maven BuildLicense
LmdbJava Benchmarks
Just want the latest results?
View them here!
This is a JMH benchmark
of open source, embedded, memory-mapped, key-value stores available from Java:
(**) does not support ordered keys, so iteration benchmarks not performed
The benchmark itself is adapted from LMDB's
db_bench_mdb.cc, which in
turn is adapted from
LevelDB's benchmark.
The benchmark includes:
  • Writing data
  • Reading all data via each key
  • Reading all data via a reverse iterator
  • Reading all data via a forward iterator
  • Reading all data via a forward iterator and computing a CRC32 (via JDK API)
  • Reading all data via a forward iterator and computing a XXH64
(via extremely fastZero-Allocation-Hashing)
Byte arrays (byte[]) are always used for the keys and values, avoiding any
serialization library overhead. For those libraries that support compression,
it is disabled in the benchmark. In general any special library features that
decrease latency (eg batch modes, disable auto-commit, disable journals,
hint at expected data sizes etc) were used. While we have tried to be fair and
consistent, some libraries offer non-obvious tuning settings or usage patterns
that might further reduce their latency. We do not claim we have exhausted
every tuning option every library exposes, but pull requests are most welcome.
Usage
This benchmark uses POSIX calls to accurately determine consumed disk space and
only depends on Linux-specific native library wrappers where a range of such
wrappers exists. Operation on non-Linux operating systems is unsupported.
  1. Clone this repository and mvn clean package
  2. Run the benchmark with java -jar target/benchmarks.jar
The benchmark offers many parameters, but to reduce execution time they default
to a fast, mechanically-sympathetic workload (ie integer keys, sequential IO)
that should fit in RAM. A default execution takes around 15 minutes on
server-grade hardware (ie 2 x Intel Xeon E5-2667 v3 CPUs, 512 GB RAM etc).
You can append -h to the java -jar line for JMH help. For example, use:
  • -foe true to stop on any error (recommended)
  • -rf csv to emit a CSV results file (recommended)
  • -f 3 to run three forks for smaller error ranges (recommended)
  • -lp to list all available parameters
  • -p intKey=true,false to test both integer and string-based keys
The parameters (available from -lp) allow you to create workloads of different
iteration counts (num), key sizes and layout (intKey), value sizes
(valSize), mechanical sympathy (sequential, valRandom) and feature tuning
(eg forceSafe, writeMap etc).
System.out will display the actual on-disk usage of each implementation as
"Bytes" \t longVal \t benchId lines. This is not the "apparent" size (given
sparse files are typical), but the actual on-disk space used. The underlying
storage location defaults to the temporary file system. To force an alternate
location, invoke Java with -Djava.io.tmpdir=/somewhere/you/like.
Support
Please open a GitHub issue
if you have any questions.
Contributing
Contributions are welcome! Please see the LmdbJava project's
Contributing Guidelines.
License
This project is licensed under the
Apache License, Version 2.0.
About
Benchmark of open source, embedded, memory-mapped, key-value stores available from Java (JMH)
Resources
Readme
License
Contributing
Contributing
Activity
Stars
0 stars
Watchers
0 watching
Forks
0 forks
Report repository
Releases
Packages
Contributors
Languages