diff --git a/.gitignore b/.gitignore
index ae58d2e..37ea030 100644
--- a/.gitignore
+++ b/.gitignore
@@ -89,3 +89,6 @@ target
 #vscode
 .vscode
 build
+
+# git worktrees
+.worktrees/
diff --git a/binding/erlang/Makefile b/binding/erlang/Makefile
new file mode 100644
index 0000000..d71c6d4
--- /dev/null
+++ b/binding/erlang/Makefile
@@ -0,0 +1,18 @@
+.PHONY: all compile test clean bench-v4 bench-v6
+
+all: compile
+
+compile:
+	rebar3 compile
+
+test:
+	rebar3 eunit
+
+clean:
+	rebar3 clean
+
+bench-v4:
+	sh benchmarks/xdb-benchmark.sh ipv4
+
+bench-v6:
+	sh benchmarks/xdb-benchmark.sh ipv6
diff --git a/binding/erlang/README.md b/binding/erlang/README.md
index 08b9999..15cbe74 100644
--- a/binding/erlang/README.md
+++ b/binding/erlang/README.md
@@ -1,10 +1,10 @@
 :globe_with_meridians: [中文简体](README_zh.md) | [English](README.md)
 
-# ip2region erlang query client
+# ip2region Erlang query client
 
 ### Introduction
 
-This binding implements the xdb query client in Erlang, based on the Erlang OTP Application. The query logic is implemented by the `ip2region_worker` worker process, supporting multiple worker processes for load balancing.
+This binding implements the xdb query client in `Erlang`, based on the `Erlang OTP Application`. The query logic is implemented by the `ip2region_worker` worker process, supporting multiple worker processes for load balancing.
 
 ### Application Configuration
 
@@ -15,13 +15,35 @@ The configurable parameters for this application are in `ip2region.app.src`, as
     {poolargs, [
         {size, 1},  %% Default number of worker processes
         {max_overflow, 5}  %% Maximum number of worker processes
+    ]},
+    {db, [
+        {ipv4, "ip2region.xdb"}  %% Default IPv4 xdb file
     ]}
   ]}
 ```
 
+### Dual-stack configuration (IPv4 + IPv6)
+
+To enable IPv6 queries, add the `ipv6` entry to the `db` list and place both xdb files under `priv/`:
+
+```erlang
+  {env,[
+    {poolargs, [
+        {size, 1},
+        {max_overflow, 5}
+    ]},
+    {db, [
+        {ipv4, "ip2region.xdb"},
+        {ipv6, "ip2region_v6.xdb"}
+    ]}
+  ]}
+```
+
+The `xdb:search/1` interface automatically detects IPv4 and IPv6 inputs and routes them to the correct worker pool.
+
 ### Compile
 
-```
+```bash
 $ rebar3 compile
 ```
 
@@ -29,113 +51,130 @@ $ rebar3 compile
 
 Place the xdb file in the `priv` directory, then start the Erlang node:
 
-```
+```bash
 $ rebar3 shell
 ```
 
-Call the `xdb:search/1` interface in the Erlang shell to query IP address information. This interface supports IP addresses represented as list strings, binary strings, tuples, and integers, as follows:
+Call the `xdb:search/1` interface in the Erlang shell to query IP address information. This interface supports IP addresses represented as list strings, binary strings, tuples, and integers:
 
-```
+```erlang
 1> xdb:search("1.0.8.0").
-[20013,22269,124,48,124,24191,19996,30465,124,24191,24030,
- 24066,124,30005,20449]
+[20013,22269,124,24191,19996,30465,124,24191,24030,24066,
+ 124,20013,22269,30005,20449,124,67,78]
 2>
 3> io:format("~ts~n", [xdb:search("1.0.8.0")]).
-中国|0|广东省|广州市|电信
-io:format("~ts~n", [xdb:search(<<"1.0.8.0">>)]).
-中国|0|广东省|广州市|电信
-4> io:format("~ts~n", [xdb:search({1,0,8,0})]).
-中国|0|广东省|广州市|电信
+中国|广东省|广州市|中国电信|CN
+4> io:format("~ts~n", [xdb:search(<<"1.0.8.0">>)]).
+中国|广东省|广州市|中国电信|CN
+5> io:format("~ts~n", [xdb:search({1,0,8,0})]).
+中国|广东省|广州市|中国电信|CN
 6> io:format("~ts~n", [xdb:search(16779264)]).
-中国|0|广东省|广州市|电信
+中国|广东省|广州市|中国电信|CN
+```
+
+With dual-stack enabled, IPv6 addresses are supported in the same way:
+
+```erlang
+1> io:format("~ts~n", [xdb:search("2001:4860:4860::8888")]).
+United States|Florida|Miami|Google LLC|US
+2> io:format("~ts~n", [xdb:search(<<"2001:4860:4860::8888">>)]).
+United States|Florida|Miami|Google LLC|US
+3> io:format("~ts~n", [xdb:search({8193,18528,18528,0,0,0,0,34952})]).
+United States|Florida|Miami|Google LLC|US
 ```
 
 ### Usage
 
-* Add the dependency in `rebar.config`
+- Add the dependency in `rebar.config`
 
-```
+```erlang
 {deps, [
   ip2region
 ]}.
 ```
 
-* Start the ip2region Application
+- Start the ip2region Application
 
-```
-......
-
-application:ensure_started(ip2region),
-
-......
+```erlang
+{ok, _} = application:ensure_all_started(ip2region).
 ```
 
-* Call the `xdb:search/1` interface to query IP information
+- Call the `xdb:search/1` interface to query IP information
 
-```
-......
-
-ip2region:search("1.0.8.0"),
-
-......
+```erlang
+xdb:search("1.0.8.0").
 ```
 
 ### Unit Test
 
-```
+```bash
 $ rebar3 eunit
 ===> Verifying dependencies...
 ===> Analyzing applications...
 ===> Compiling ip2region
 ===> Performing EUnit tests...
-=INFO REPORT==== 17-Jan-2023::11:52:59.920155 ===
-XdbFile:/home/admin/erl-workspace/ip2region/binding/erlang/_build/test/lib/ip2region/priv/ip2region.xdb
+=INFO REPORT==== 28-Jun-2026::04:53:28 ===
+XdbFile:/Users/nana/Documents/code/ip2region/.worktrees/erlang-ipv6/binding/erlang/_build/test/lib/ip2region/priv/ip2region.xdb
 
 ....
-Finished in 0.074 seconds
-4 tests, 0 failures
+Finished in 0.192 seconds
+63 tests, 0 failures
 ```
 
 ### Benchmark
 
-```
+Both IPv4 and IPv6 benchmarks share the same script. Run it with the desired IP version:
+
+> `cold` = first pass over the source file: each IP triggers a real search and the
+> result is written into the ETS cache. `warm` = second pass over the same list,
+> where every lookup is served directly from the ETS cache.
+
+```bash
 $ cd benchmarks/
-$ sh xdb-benchmark.sh
-===> Verifying dependencies...
-===> Analyzing applications...
-===> Compiling ip2region
-Erlang/OTP 24 [erts-12.3.2.2] [source] [64-bit] [smp:2:2] [ds:2:2:10] [async-threads:1] [jit]
-
-Eshell V12.3.2.2  (abort with ^G)
-1> =INFO REPORT==== 17-Jan-2023::11:37:35.631095 ===
-XdbFile:/home/admin/erl-workspace/ip2region/binding/erlang/_build/default/lib/ip2region/priv/ip2region.xdb
-
-===> Booted ip2region
-===> Evaluating: "xdb_benchmark:main(\"../../data/ip.merge.txt\"), init:stop()."
-CPU info:
-model name      : AMD EPYC 7K62 48-Core Processor
-cache size      : 512 KB
-cpu MHz         : 2595.124
-bogomips        : 5190.24
-cores/threads   : 2
-
-Erlang info:
-system_version:Erlang/OTP 24 [erts-12.3.2.2] [source] [64-bit] [smp:2:2] [ds:2:2:10] [async-threads:1] [jit]
-load test data use 4.835593s
-
-start run benchmark tests
-
-search from file:
-ip count:683844,
-total time: 28.201699s,
-search 24248.326315375536 times per second,
-use 41.23995969841075 micro second per search
-
-search from cache:
-ip count:683844,
-total time: 0.671801s,
-search 1017926.4395259906 times per second,
-use 0.9823892583688677 micro second per search
-
-benchmark test finish
+$ sh xdb-benchmark.sh ipv4
+```
+
+For IPv6:
+
+```bash
+$ sh xdb-benchmark.sh ipv6
+```
+
+Or use the Makefile targets from the `binding/erlang` directory:
+
+```bash
+$ make bench-v4
+$ make bench-v6
+```
+
+#### IPv4 benchmark example
+
+```bash
+System:
+  CPU    : Apple M4
+  Cores  : 10 cores / 10 threads
+  Erlang : Erlang/OTP 29 [erts-17.0.2] [source] [64-bit] [smp:10:10] [ds:10:10:10] [async-threads:1] [jit] [dtrace]
+  Loaded : 487169 IPs in 1.335 s
+
+Benchmarks:
+  cold      total=  9.601s  count= 487169  qps=    50740.66  avg= 0.019708 ms/op (19.708 us/op)
+  warm      total=  0.160s  count= 487169  qps=  3053164.29  avg= 0.000328 ms/op ( 0.328 us/op)
+
+Done.
+```
+
+#### IPv6 benchmark example
+
+```bash
+System:
+  CPU    : Apple M4
+  Cores  : 10 cores / 10 threads
+  Erlang : Erlang/OTP 29 [erts-17.0.2] [source] [64-bit] [smp:10:10] [ds:10:10:10] [async-threads:1] [jit] [dtrace]
+  Loaded : 638953 IPs in 2.949 s
+
+Benchmarks:
+  cold      total= 20.504s  count= 638953  qps=    31162.52  avg= 0.032090 ms/op (32.090 us/op)
+  warm      total=  0.444s  count= 638953  qps=  1437781.56  avg= 0.000696 ms/op ( 0.696 us/op)
+
+Done.
 ```
diff --git a/binding/erlang/README_zh.md b/binding/erlang/README_zh.md
index 0ebc6d6..bfea45b 100644
--- a/binding/erlang/README_zh.md
+++ b/binding/erlang/README_zh.md
@@ -1,128 +1,179 @@
 :globe_with_meridians: [中文简体](README_zh.md) | [English](README.md)
 
-# ip2region erlang 查询客户端
+# ip2region Erlang 查询客户端
 
 ### 简介
-该bingding以erlang语言实现xdb查询客户端，基于Erlang OTP Application，查询逻辑由ip2region_worker工作进程实现，支持配多个工作进程来进行负载均衡。
+
+该 bingding 以 `Erlang` 语言实现 xdb 查询客户端，基于 `Erlang OTP Application`，查询逻辑由 `ip2region_worker` 工作进程实现，支持配多个工作进程来进行负载均衡。
 
 ### 应用配置
-该应用可配置的参数在ip2region.app.src中,如下：
-``` erlang
+
+该应用可配置的参数在 `ip2region.app.src` 中, 如下：
+
+```erlang
   {env,[
     {poolargs, [
         {size, 1},  %% 工作进程默认数量
         {max_overflow, 5}  %% 工作进程最大数量
+    ]},
+    {db, [
+        {ipv4, "ip2region.xdb"}  %% 默认 IPv4 xdb 文件
     ]}
   ]}
 ```
 
+### 双栈配置（IPv4 + IPv6）
+
+如需启用 IPv6 查询，在 `db` 列表中加入 `ipv6` 项，并将两个 xdb 文件放到 `priv/` 目录下：
+
+```erlang
+  {env,[
+    {poolargs, [
+        {size, 1},
+        {max_overflow, 5}
+    ]},
+    {db, [
+        {ipv4, "ip2region.xdb"},
+        {ipv6, "ip2region_v6.xdb"}
+    ]}
+  ]}
+```
+
+`xdb:search/1` 接口会自动识别 IPv4 与 IPv6 输入，并将其路由到对应的工作进程池。
+
 ### 编译
 
-```
+```bash
 $ rebar3 compile
 ```
 
 ### 运行
-将xdb文件放到priv目录下，然后启动erlang节点：
-```
+
+将 xdb 文件放到 `priv` 目录下，然后启动 Erlang 节点：
+
+```bash
 $ rebar3 shell
 ```
-在erlang shell中调用xdb:search/1接口查询Ip地址信息, 该接口支持以list格式字符串、binary格式字符串、tuple和整数表示的IP地址，如下：
-```
+
+在 Erlang shell 中调用 `xdb:search/1` 接口查询 IP 地址信息。该接口支持 list 字符串、binary 字符串、tuple 和整数表示的 IP 地址：
+
+```erlang
 1> xdb:search("1.0.8.0").
-[20013,22269,124,48,124,24191,19996,30465,124,24191,24030,
- 24066,124,30005,20449]
+[20013,22269,124,24191,19996,30465,124,24191,24030,24066,
+ 124,20013,22269,30005,20449,124,67,78]
 2>
 3> io:format("~ts~n", [xdb:search("1.0.8.0")]).
-中国|0|广东省|广州市|电信
-io:format("~ts~n", [xdb:search(<<"1.0.8.0">>)]).
-中国|0|广东省|广州市|电信
-4> io:format("~ts~n", [xdb:search({1,0,8,0})]).
-中国|0|广东省|广州市|电信
+中国|广东省|广州市|中国电信|CN
+4> io:format("~ts~n", [xdb:search(<<"1.0.8.0">>)]).
+中国|广东省|广州市|中国电信|CN
+5> io:format("~ts~n", [xdb:search({1,0,8,0})]).
+中国|广东省|广州市|中国电信|CN
 6> io:format("~ts~n", [xdb:search(16779264)]).
-中国|0|广东省|广州市|电信
+中国|广东省|广州市|中国电信|CN
+```
+
+启用双栈后，IPv6 地址也按同样方式支持：
+
+```erlang
+1> io:format("~ts~n", [xdb:search("2001:4860:4860::8888")]).
+United States|Florida|Miami|Google LLC|US
+2> io:format("~ts~n", [xdb:search(<<"2001:4860:4860::8888">>)]).
+United States|Florida|Miami|Google LLC|US
+3> io:format("~ts~n", [xdb:search({8193,18528,18528,0,0,0,0,34952})]).
+United States|Florida|Miami|Google LLC|US
 ```
 
 ### 使用方法
-* 在rebar.config中引入依赖
-```
+
+- 在 `rebar.config` 中引入依赖
+
+```erlang
 {deps, [
   ip2region
 ]}.
 ```
-* 启动ip2region Application
-```
-......
 
-application:ensure_started(ip2region),
+- 启动 ip2region Application
 
-......
+```erlang
+{ok, _} = application:ensure_all_started(ip2region).
 ```
 
-* 调用xdb:search/1接口查询IP信息
-```
-......
+- 调用 `xdb:search/1` 接口查询 IP 信息
 
-ip2region:search("1.0.8.0"),
-
-......
+```erlang
+xdb:search("1.0.8.0").
 ```
 
 ### 单元测试
 
-```
+```bash
 $ rebar3 eunit
 ===> Verifying dependencies...
 ===> Analyzing applications...
 ===> Compiling ip2region
 ===> Performing EUnit tests...
-=INFO REPORT==== 17-Jan-2023::11:52:59.920155 ===
-XdbFile:/home/admin/erl-workspace/ip2region/binding/erlang/_build/test/lib/ip2region/priv/ip2region.xdb
+=INFO REPORT==== 28-Jun-2026::04:53:28 ===
+XdbFile:/Users/nana/Documents/code/ip2region/.worktrees/erlang-ipv6/binding/erlang/_build/test/lib/ip2region/priv/ip2region.xdb
 
 ....
-Finished in 0.074 seconds
-4 tests, 0 failures
+Finished in 0.192 seconds
+63 tests, 0 failures
 ```
 
 ### 基准测试
-```
+
+IPv4 与 IPv6 共用一个脚本，通过参数指定版本：
+
+> `cold` = 第一次遍历源文件：每个 IP 都会触发真实查询，并把结果写入 ETS 缓存。
+> `warm` = 第二次遍历同一列表，所有查询都直接命中 ETS 缓存。
+
+```bash
 $ cd benchmarks/
-$ sh xdb-benchmark.sh
-===> Verifying dependencies...
-===> Analyzing applications...
-===> Compiling ip2region
-Erlang/OTP 24 [erts-12.3.2.2] [source] [64-bit] [smp:2:2] [ds:2:2:10] [async-threads:1] [jit]
-
-Eshell V12.3.2.2  (abort with ^G)
-1> =INFO REPORT==== 17-Jan-2023::11:37:35.631095 ===
-XdbFile:/home/admin/erl-workspace/ip2region/binding/erlang/_build/default/lib/ip2region/priv/ip2region.xdb
-
-===> Booted ip2region
-===> Evaluating: "xdb_benchmark:main(\"../../data/ip.merge.txt\"), init:stop()."
-CPU info:
-model name      : AMD EPYC 7K62 48-Core Processor
-cache size      : 512 KB
-cpu MHz         : 2595.124
-bogomips        : 5190.24
-cores/threads   : 2
-
-Erlang info:
-system_version:Erlang/OTP 24 [erts-12.3.2.2] [source] [64-bit] [smp:2:2] [ds:2:2:10] [async-threads:1] [jit]
-load test data use 4.835593s
-
-start run benchmark tests
-
-search from file:
-ip count:683844,
-total time: 28.201699s,
-search 24248.326315375536 times per second,
-use 41.23995969841075 micro second per search
-
-search from cache:
-ip count:683844,
-total time: 0.671801s,
-search 1017926.4395259906 times per second,
-use 0.9823892583688677 micro second per search
-
-benchmark test finish
+$ sh xdb-benchmark.sh ipv4
+```
+
+IPv6：
+
+```bash
+$ sh xdb-benchmark.sh ipv6
+```
+
+也可以在 `binding/erlang` 目录直接用 Makefile：
+
+```bash
+$ make bench-v4
+$ make bench-v6
+```
+
+#### IPv4 基准测试示例
+
+```bash
+System:
+  CPU    : Apple M4
+  Cores  : 10 cores / 10 threads
+  Erlang : Erlang/OTP 29 [erts-17.0.2] [source] [64-bit] [smp:10:10] [ds:10:10:10] [async-threads:1] [jit] [dtrace]
+  Loaded : 487169 IPs in 1.335 s
+
+Benchmarks:
+  cold      total=  9.601s  count= 487169  qps=    50740.66  avg= 0.019708 ms/op (19.708 us/op)
+  warm      total=  0.160s  count= 487169  qps=  3053164.29  avg= 0.000328 ms/op ( 0.328 us/op)
+
+Done.
+```
+
+#### IPv6 基准测试示例
+
+```bash
+System:
+  CPU    : Apple M4
+  Cores  : 10 cores / 10 threads
+  Erlang : Erlang/OTP 29 [erts-17.0.2] [source] [64-bit] [smp:10:10] [ds:10:10:10] [async-threads:1] [jit] [dtrace]
+  Loaded : 638953 IPs in 2.949 s
+
+Benchmarks:
+  cold      total= 20.504s  count= 638953  qps=    31162.52  avg= 0.032090 ms/op (32.090 us/op)
+  warm      total=  0.444s  count= 638953  qps=  1437781.56  avg= 0.000696 ms/op ( 0.696 us/op)
+
+Done.
 ```
diff --git a/binding/erlang/benchmarks/xdb-benchmark.sh b/binding/erlang/benchmarks/xdb-benchmark.sh
index 40d13f3..77b647b 100755
--- a/binding/erlang/benchmarks/xdb-benchmark.sh
+++ b/binding/erlang/benchmarks/xdb-benchmark.sh
@@ -1,5 +1,37 @@
 #!/bin/bash
+set -e
 
-cd ..
+# Run from binding/erlang so paths and rebar3 artifacts are correct.
+cd "$(dirname "$0")/.."
 
-rebar3 shell --eval="xdb_benchmark:main(\"../../data/ip.merge.txt\"), init:stop()."
+VERSION="${1:-ipv4}"
+PROJECT_ROOT="$(cd ../.. && pwd)"
+
+if [ "$VERSION" = "ipv6" ]; then
+    DB_FILE="${PROJECT_ROOT}/data/ip2region_v6.xdb"
+    DATA_FILE="${PROJECT_ROOT}/data/ipv6_source.txt"
+    DB_CONFIG="[{ipv6, \"${DB_FILE}\"}]"
+elif [ "$VERSION" = "ipv4" ]; then
+    DATA_FILE="${PROJECT_ROOT}/data/ipv4_source.txt"
+    DB_CONFIG="[{ipv4, \"ip2region.xdb\"}]"
+else
+    echo "Usage: $0 [ipv4|ipv6]"
+    exit 1
+fi
+
+rebar3 compile
+
+# shellcheck disable=SC2089
+EVAL="application:load(ip2region), \
+application:set_env(ip2region, db, ${DB_CONFIG}), \
+application:set_env(ip2region, poolargs, [{size,4},{max_overflow,8}]), \
+{ok,_}=application:ensure_all_started(ip2region), \
+xdb_benchmark:main(\"${DATA_FILE}\"), \
+init:stop()."
+
+# shellcheck disable=SC2090
+erl -pa _build/default/lib/poolboy/ebin \
+    -pa _build/default/lib/ip2region/ebin \
+    -kernel logger_level error \
+    -noshell \
+    -eval "${EVAL}"
diff --git a/binding/erlang/include/ip2region.hrl b/binding/erlang/include/ip2region.hrl
index a0e91e7..b08a7f4 100644
--- a/binding/erlang/include/ip2region.hrl
+++ b/binding/erlang/include/ip2region.hrl
@@ -4,23 +4,39 @@
 -define(NONE, none).
 -define(APP_NAME, ip2region).
 
--define(XDB_VECTOR_INDEX, ets_xdb_vector_index).
--define(XDB_SEGMENT_INDEX, ets_xdb_segement_index).
--define(IP2REGION_CACHE, ets_ip2region_cache).
-
-
 -define(XDB_HEADER_SIZE, 256).
 -define(XDB_VECTOR_COLS, 256).
--define(XDB_VECTOR_INDEX_SIZE, 8). 
+-define(XDB_VECTOR_INDEX_SIZE, 8).
 -define(XDB_VECTOR_INDEX_COUNT, (16#10000)). %% 256*256
 
--define(XDB_SEGMENT_INDEX_SIZE, 14).
+%% IP versions as stored in xdb header
+-define(IP_VERSION_4, 4).
+-define(IP_VERSION_6, 6).
 
--define(IP2REGION_POOL, ip2region_pool).
+%% Segment index sizes (bytes): start_ip + end_ip + data_len + data_ptr
+-define(XDB_SEGMENT_INDEX_SIZE_V4, 14).  %% 4 + 4 + 2 + 4
+-define(XDB_SEGMENT_INDEX_SIZE_V6, 38).  %% 16 + 16 + 2 + 4
+
+%% Per-version ETS tables
+-define(XDB_VECTOR_INDEX_V4, ets_xdb_vector_index_v4).
+-define(XDB_VECTOR_INDEX_V6, ets_xdb_vector_index_v6).
+-define(XDB_SEGMENT_INDEX_V4, ets_xdb_segment_index_v4).
+-define(XDB_SEGMENT_INDEX_V6, ets_xdb_segment_index_v6).
+-define(IP2REGION_CACHE_V4, ets_ip2region_cache_v4).
+-define(IP2REGION_CACHE_V6, ets_ip2region_cache_v6).
+
+%% Per-version pool names.
+-define(IP2REGION_POOL_V4, ip2region_pool_v4).
+-define(IP2REGION_POOL_V6, ip2region_pool_v6).
+
+-record(xdb_header, {
+    version :: non_neg_integer(),
+    index_policy :: non_neg_integer(),
+    created_at :: non_neg_integer(),
+    start_index_ptr :: non_neg_integer(),
+    end_index_ptr :: non_neg_integer(),
+    ip_version :: non_neg_integer(),
+    runtime_ptr_bytes :: non_neg_integer()
+}).
 
--ifndef(IF).
--define(IF(C, T, F), case (C) of true -> (T); false -> (F) end).
--define(IF(C, T), ?IF(C, T, skip)).
 -endif.
-
--endif.
\ No newline at end of file
diff --git a/binding/erlang/rebar.config b/binding/erlang/rebar.config
index 076f916..dd1affa 100644
--- a/binding/erlang/rebar.config
+++ b/binding/erlang/rebar.config
@@ -1,6 +1,6 @@
 {erl_opts, [
-    debug_info, 
-    export_all, 
+    debug_info,
+    export_all,
     nowarn_export_all
 ]}.
 
@@ -18,7 +18,7 @@
 {ex_doc, [
     {extras, ["README.md"]},
     {main, "README.md"},
-    {source_url, "https://github.com/leihua996/ip2region/tree/master/binding/erlang"}
+    {source_url, "https://github.com/lionsoul2014/ip2region/tree/master/binding/erlang"}
 ]}.
 
 {hex, [{doc, ex_doc}]}.
diff --git a/binding/erlang/src/ip2region.app.src b/binding/erlang/src/ip2region.app.src
index 4de369c..9188b34 100644
--- a/binding/erlang/src/ip2region.app.src
+++ b/binding/erlang/src/ip2region.app.src
@@ -5,16 +5,20 @@
   {mod, {ip2region_app, []}},
   {applications,
    [kernel,
-    stdlib
+    stdlib,
+    poolboy
    ]},
   {env,[
     {poolargs, [
         {size, 1},
         {max_overflow, 5}
+    ]},
+    {db, [
+        {ipv4, "ip2region.xdb"}
     ]}
   ]},
   {modules, []},
 
   {licenses, ["Apache-2.0"]},
-  {links, [{"Github", "https://github.com/leihua996/ip2region/tree/master/binding/erlang"}]}
+  {links, [{"Github", "https://github.com/lionsoul2014/ip2region/tree/master/binding/erlang"}]}
  ]}.
diff --git a/binding/erlang/src/ip2region_sup.erl b/binding/erlang/src/ip2region_sup.erl
index 304bc98..7b07742 100644
--- a/binding/erlang/src/ip2region_sup.erl
+++ b/binding/erlang/src/ip2region_sup.erl
@@ -2,7 +2,7 @@
 %% Copyright 2022 The Ip2Region Authors. All rights reserved.
 %% Use of this source code is governed by a Apache2.0-style
 %% license that can be found in the LICENSE file.
-%% 
+%%
 %% @doc ip2region top level supervisor.
 %% @end
 %%%-------------------------------------------------------------------
@@ -18,7 +18,6 @@
 
 start_link() ->
     {ok, SupPid} = supervisor:start_link({local, ?SERVER}, ?MODULE, []),
-    {ok, _PoolPid} = start_ip2region_pool(SupPid),
     {ok, SupPid}.
 
 %% sup_flags() = #{strategy => strategy(),         % optional
@@ -35,21 +34,45 @@ init([]) ->
     SupFlags = #{strategy => one_for_one,
                  intensity => 10,
                  period => 5},
-    ChildSpecs = [],
+    ChildSpecs = pool_child_specs(),
     {ok, {SupFlags, ChildSpecs}}.
 
 %% internal functions
-%% 
+%%
 create_table() ->
     Opts = [named_table, set, public, {read_concurrency, true}, {keypos, 1}],
-    ets:new(?XDB_VECTOR_INDEX, Opts),
-    ets:new(?XDB_SEGMENT_INDEX, Opts),
-    ets:new(?IP2REGION_CACHE, Opts).
+    %% Version-specific tables for dual-stack support
+    ensure_table(?XDB_VECTOR_INDEX_V4, Opts),
+    ensure_table(?XDB_VECTOR_INDEX_V6, Opts),
+    ensure_table(?XDB_SEGMENT_INDEX_V4, Opts),
+    ensure_table(?XDB_SEGMENT_INDEX_V6, Opts),
+    ensure_table(?IP2REGION_CACHE_V4, Opts),
+    ensure_table(?IP2REGION_CACHE_V6, Opts).
 
-start_ip2region_pool(Sup) ->
+ensure_table(Name, Opts) ->
+    case ets:whereis(Name) of
+        undefined -> ets:new(Name, Opts);
+        _ -> ok
+    end.
+
+pool_child_specs() ->
+    {ok, DbConfig} = application:get_env(db),
     {ok, PoolArgsCfg} = application:get_env(poolargs),
-    PoolName = ?IP2REGION_POOL,
-    PoolArgs = [{strategy, fifo}, {name, {local, PoolName}}, {worker_module, ip2region_worker} | PoolArgsCfg],
-    WorkerArgs = [],
-    ChildSpecs = poolboy:child_spec(PoolName, PoolArgs, WorkerArgs),
-    supervisor:start_child(Sup, ChildSpecs).
\ No newline at end of file
+    lists:foldl(
+        fun({ipv4, File}, Acc) ->
+                [make_pool_spec(?IP2REGION_POOL_V4, ipv4, File, PoolArgsCfg) | Acc];
+           ({ipv6, File}, Acc) ->
+                [make_pool_spec(?IP2REGION_POOL_V6, ipv6, File, PoolArgsCfg) | Acc];
+           (_, Acc) ->
+                Acc
+        end, [], DbConfig).
+
+make_pool_spec(PoolName, Version, File, PoolArgsCfg) ->
+    PoolArgs = [
+        {strategy, fifo},
+        {name, {local, PoolName}},
+        {worker_module, ip2region_worker}
+        | PoolArgsCfg
+    ],
+    WorkerArgs = [{xdb_file, File}, {expected_version, Version}],
+    poolboy:child_spec(PoolName, PoolArgs, WorkerArgs).
diff --git a/binding/erlang/src/ip2region_util.erl b/binding/erlang/src/ip2region_util.erl
index 0359b85..d84dd56 100644
--- a/binding/erlang/src/ip2region_util.erl
+++ b/binding/erlang/src/ip2region_util.erl
@@ -2,25 +2,70 @@
 %% Copyright 2022 The Ip2Region Authors. All rights reserved.
 %% Use of this source code is governed by a Apache2.0-style
 %% license that can be found in the LICENSE file.
-%% 
-%% @doc 
-%% ip2region utils
+%%
+%% @doc
+%% ip2region utils: IPv4/IPv6 parsing and version detection.
 %% @end
 %%%-------------------------------------------------------------------
 -module(ip2region_util).
--export([ipv4_to_n/1]).
 
+-export([ipv4_to_n/1, ip_version/1, ip_to_bytes/1]).
 
-ipv4_to_n(IntIp) when is_integer(IntIp) -> IntIp;
-ipv4_to_n({A, B, C, D}) ->
-	<<N:32>> = <<A, B, C, D>>,
-	N;
-ipv4_to_n(Ip) when is_binary(Ip) ->
-	ipv4_to_n(binary_to_list(Ip));
-ipv4_to_n(Ip) when is_list(Ip) ->
+-define(IS_UINT8(V), is_integer(V), V >= 0, V =< 255).
+-define(IS_UINT16(V), is_integer(V), V >= 0, V =< 65535).
+
+-spec ip_version(Ip :: tuple() | list() | binary() | integer()) ->
+    ipv4 | ipv6 | {error, atom()}.
+ip_version(Ip) when is_integer(Ip), Ip >= 0, Ip =< 16#FFFFFFFF -> ipv4;
+ip_version({A, B, C, D}) when ?IS_UINT8(A), ?IS_UINT8(B), ?IS_UINT8(C), ?IS_UINT8(D) -> ipv4;
+ip_version({A, B, C, D, E, F, G, H}) when ?IS_UINT16(A), ?IS_UINT16(B), ?IS_UINT16(C), ?IS_UINT16(D),
+                                            ?IS_UINT16(E), ?IS_UINT16(F), ?IS_UINT16(G), ?IS_UINT16(H) -> ipv6;
+ip_version(Ip) when is_binary(Ip) ->
+    ip_version(binary_to_list(Ip));
+ip_version(Ip) when is_list(Ip) ->
     case inet_parse:address(Ip) of
-        {ok, Addr} ->
-            ipv4_to_n(Addr);
+        {ok, {_, _, _, _}} -> ipv4;
+        {ok, {_, _, _, _, _, _, _, _}} -> ipv6;
+        _ -> {error, bad_ip_format}
+    end;
+ip_version(_) ->
+    {error, bad_ip_format}.
+
+-spec ip_to_bytes(Ip :: tuple() | list() | binary() | integer()) ->
+    {ok, ipv4 | ipv6, binary()} | {error, atom()}.
+ip_to_bytes(Ip) when is_integer(Ip), Ip >= 0, Ip =< 16#FFFFFFFF ->
+    {ok, ipv4, <<Ip:32>>};
+ip_to_bytes({A, B, C, D}) when ?IS_UINT8(A), ?IS_UINT8(B), ?IS_UINT8(C), ?IS_UINT8(D) ->
+    {ok, ipv4, <<A, B, C, D>>};
+ip_to_bytes({A, B, C, D, E, F, G, H}) when ?IS_UINT16(A), ?IS_UINT16(B), ?IS_UINT16(C), ?IS_UINT16(D),
+                                              ?IS_UINT16(E), ?IS_UINT16(F), ?IS_UINT16(G), ?IS_UINT16(H) ->
+    {ok, ipv6, <<A:16, B:16, C:16, D:16, E:16, F:16, G:16, H:16>>};
+ip_to_bytes(Ip) when is_binary(Ip) ->
+    ip_to_bytes(binary_to_list(Ip));
+ip_to_bytes(Ip) when is_list(Ip) ->
+    case inet_parse:address(Ip) of
+        {ok, {A, B, C, D}} ->
+            {ok, ipv4, <<A, B, C, D>>};
+        {ok, {A, B, C, D, E, F, G, H}} ->
+            {ok, ipv6, <<A:16, B:16, C:16, D:16, E:16, F:16, G:16, H:16>>};
         _ ->
             {error, bad_ip_format}
-    end.
\ No newline at end of file
+    end;
+ip_to_bytes(_) ->
+    {error, bad_ip_format}.
+
+-spec ipv4_to_n(Ip :: tuple() | list() | binary() | integer()) ->
+    non_neg_integer() | {error, atom()}.
+ipv4_to_n(IntIp) when is_integer(IntIp), IntIp >= 0, IntIp =< 16#FFFFFFFF -> IntIp;
+ipv4_to_n({A, B, C, D}) when ?IS_UINT8(A), ?IS_UINT8(B), ?IS_UINT8(C), ?IS_UINT8(D) ->
+    <<N:32>> = <<A, B, C, D>>,
+    N;
+ipv4_to_n(Ip) when is_binary(Ip) ->
+    ipv4_to_n(binary_to_list(Ip));
+ipv4_to_n(Ip) when is_list(Ip) ->
+    case ip_to_bytes(Ip) of
+        {ok, ipv4, <<N:32>>} -> N;
+        _ -> {error, bad_ip_format}
+    end;
+ipv4_to_n(_) ->
+    {error, bad_ip_format}.
diff --git a/binding/erlang/src/ip2region_worker.erl b/binding/erlang/src/ip2region_worker.erl
index 64d039c..90d9152 100644
--- a/binding/erlang/src/ip2region_worker.erl
+++ b/binding/erlang/src/ip2region_worker.erl
@@ -2,9 +2,9 @@
 %% Copyright 2022 The Ip2Region Authors. All rights reserved.
 %% Use of this source code is governed by a Apache2.0-style
 %% license that can be found in the LICENSE file.
-%% 
-%% @doc 
-%% ip2region xdb client worker
+%%
+%% @doc
+%% ip2region xdb client worker, now version-aware (IPv4/IPv6).
 %% @end
 %%%-------------------------------------------------------------------
 -module(ip2region_worker).
@@ -15,7 +15,11 @@
 -export([start/1, stop/1, start_link/1]).
 -export([search/2]).
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
--record(state, {xdb_fd}).
+
+-record(state, {
+    xdb_fd,
+    version :: ipv4 | ipv6
+}).
 
 %%==========================================
 %% API
@@ -28,7 +32,6 @@ start_link(Args) ->
     Opts = [{spawn_opt, [{min_heap_size, 6000}]}],
     gen_server:start_link(?MODULE, Args, Opts).
 
-
 stop(Pid) ->
     gen_server:call(Pid, stop).
 
@@ -38,26 +41,46 @@ search(Pid, Ip) ->
 %%==========================================
 %% gen_server callbacks
 %% =========================================
-init(_Args) ->
+init(Args) ->
     process_flag(trap_exit, true),
-    AppName = 
+    AppName =
         case application:get_application() of
             {ok, AName} -> AName;
             _ -> ?APP_NAME
         end,
     PrivDir = code:priv_dir(AppName),
-    XdbFileName = filename:join([PrivDir, "ip2region.xdb"]),
+    XdbFileName =
+        case proplists:get_value(xdb_file, Args) of
+            undefined -> filename:join([PrivDir, "ip2region.xdb"]);
+            Path ->
+                case filename:pathtype(Path) of
+                    absolute -> Path;
+                    _ -> filename:join([PrivDir, Path])
+                end
+        end,
     error_logger:info_report(io_lib:format("XdbFile:~s~n", [XdbFileName])),
     {ok, IoDevice} = file:open(XdbFileName, [read, binary]),
-    load_vector_index(IoDevice),
-    {ok, #state{xdb_fd = IoDevice}}.
+    {ok, HeaderBin} = file:read(IoDevice, ?XDB_HEADER_SIZE),
+    {ok, Header} = ip2region_xdb:parse_header(HeaderBin),
+    ExpectedVersion = proplists:get_value(expected_version, Args),
+    case resolve_version(Header) of
+        {ok, Version} when ExpectedVersion =:= undefined; ExpectedVersion =:= Version ->
+            load_vector_index(IoDevice, Version),
+            {ok, #state{xdb_fd = IoDevice, version = Version}};
+        {ok, Version} ->
+            file:close(IoDevice),
+            {stop, {xdb_version_mismatch, ExpectedVersion, Version}};
+        {error, Reason} ->
+            file:close(IoDevice),
+            {stop, Reason}
+    end.
 
 handle_call(Request, From, State) ->
     try
         do_call(Request, From, State)
     catch
         Class:Error:Stacktrace ->
-            error_logger:error_report(io_lib:format("~p handle call error, Req:~p ~p, stacktrace:~p~n", 
+            error_logger:error_report(io_lib:format("~p handle call error, Req:~p ~p, stacktrace:~p~n",
                 [?MODULE, Request, {Class, Error}, Stacktrace])),
             {reply, {error, {Class, Error}}, State}
     end.
@@ -67,7 +90,7 @@ handle_cast(Msg, State) ->
         do_cast(Msg, State)
     catch
         Class:Error:Stacktrace ->
-            error_logger:error_report(io_lib:format("~p handle cast error, Msg:~p, ~p, stacktrace:~w~n", 
+            error_logger:error_report(io_lib:format("~p handle cast error, Msg:~p, ~p, stacktrace:~w~n",
                 [?MODULE, Msg, {Class, Error}, Stacktrace])),
             {noreply, State}
     end.
@@ -77,7 +100,7 @@ handle_info(Info, State) ->
         do_info(Info, State)
     catch
         Class:Error:Stacktrace ->
-            error_logger:error_report(io_lib:format("~p handle info error, Info:~p, ~p, stacktrace:~p~n", 
+            error_logger:error_report(io_lib:format("~p handle info error, Info:~p, ~p, stacktrace:~p~n",
                 [?MODULE, Info, {Class, Error}, Stacktrace])),
             {noreply, State}
     end.
@@ -85,22 +108,19 @@ handle_info(Info, State) ->
 terminate(_Reason, State) ->
     #state{xdb_fd = XdbFd} = State,
     case is_pid(XdbFd) of
-        true ->
-            file:close(XdbFd);
-        _ ->
-            skip
+        true -> file:close(XdbFd);
+        _ -> skip
     end,
     ok.
 
 code_change(_OldVsn, State, _Extra) ->
     {ok, State}.
 
-
 %%==========================================
 %% Internal function
 %% =========================================
 do_call({search, Ip}, _From, #state{xdb_fd = IoDevice} = State) ->
-    Reply = search_ip(IoDevice, Ip),
+    Reply = search_ip(IoDevice, Ip, State),
     {reply, Reply, State};
 
 do_call(stop, _From, State) ->
@@ -108,7 +128,7 @@ do_call(stop, _From, State) ->
 
 do_call(Request, From, State) ->
     error_logger:error_report(io_lib:format("unknown request: ~p, from:~p", [Request, From])),
-    {noreply, State}.
+    {reply, {error, unknown_request}, State}.
 
 do_cast(Msg, State) ->
     error_logger:error_report(io_lib:format("unknown msg: ~p", [Msg])),
@@ -117,67 +137,105 @@ do_cast(Msg, State) ->
 do_info(Info, State) ->
     error_logger:error_report(io:format("unknown info: ~p", [Info])),
     {noreply, State}.
-    
 
-load_vector_index(IoDevice) ->
-    Key = ip2region_header_loaded,
-    case persistent_term:get(Key, false) of
-        true -> ok;
-        _ -> 
-            {ok, <<_Header:?XDB_HEADER_SIZE/binary, VectorIndexBin/binary>> } = 
-                file:read(IoDevice, ?XDB_HEADER_SIZE + ?XDB_VECTOR_INDEX_COUNT*8),
-            load_vector_index_aux(VectorIndexBin, 0),
-            persistent_term:put(Key, true)
+-spec resolve_version(#xdb_header{}) -> {ok, ipv4 | ipv6} | {error, term()}.
+resolve_version(Header) ->
+    case ip2region_xdb:header_version(Header) of
+        2 -> {ok, ipv4};
+        3 ->
+            case ip2region_xdb:header_ip_version(Header) of
+                ?IP_VERSION_4 -> {ok, ipv4};
+                ?IP_VERSION_6 -> {ok, ipv6};
+                V -> {error, {invalid_xdb_ip_version, V}}
+            end;
+        V -> {error, {invalid_xdb_version, V}}
     end.
 
-load_vector_index_aux(<<>>, _Index) -> ok;
-load_vector_index_aux(<<SPtr:32/little, EPtr:32/little, VectorIndexBin/binary>>, Index) ->
-    Term = {Index, SPtr, EPtr},
-    ets:insert(?XDB_VECTOR_INDEX, Term),
-    load_vector_index_aux(VectorIndexBin, Index + 1).
-
-
-search_ip(IoDevice, Ip) ->
-    IntIp = ip2region_util:ipv4_to_n(Ip),
-    case ets:lookup(?IP2REGION_CACHE, IntIp) of
-        [{_IntIp, RegionInfo}] ->
-            RegionInfo;
+load_vector_index(IoDevice, Version) ->
+    %% The vector index ETS table is global and shared by all pool workers.
+    %% Only the first worker (or the first worker after a restart) populates it.
+    %% Subsequent workers skip the file:read here; search_ip/2 uses file:pread/3,
+    %% so the current file pointer position does not affect correctness.
+    Table = ip2region_xdb:vector_index_table(Version),
+    case ets:info(Table, size) of
+        ?XDB_VECTOR_INDEX_COUNT ->
+            ok;
+        undefined ->
+            Opts = [named_table, set, public, {read_concurrency, true}, {keypos, 1}],
+            ets:new(Table, Opts),
+            load_vector_index_data(IoDevice, Table);
         _ ->
-            <<A:8, B:8, _Rest/binary>> = <<IntIp:32>>,
-            VectorIdx = A * ?XDB_VECTOR_COLS + B,
-            [{_, SPtr, EPtr}] = ets:lookup(?XDB_VECTOR_INDEX, VectorIdx),
-            RegionInfo = search_ip(IoDevice, IntIp, SPtr, EPtr, 0, (EPtr - SPtr) div ?XDB_SEGMENT_INDEX_SIZE),
-            ets:insert_new(?IP2REGION_CACHE, {IntIp, RegionInfo}),
-            RegionInfo
+            %% A previous worker may have crashed midway; reload to be safe.
+            load_vector_index_data(IoDevice, Table)
     end.
 
-search_ip(IoDevice, IntIp, SPtr, EPtr, Low, High) when Low =< High ->
+load_vector_index_data(IoDevice, Table) ->
+    {ok, VectorIndexBin} =
+        file:read(IoDevice, ?XDB_VECTOR_INDEX_COUNT * ?XDB_VECTOR_INDEX_SIZE),
+    load_vector_index_aux(VectorIndexBin, 0, Table).
+
+load_vector_index_aux(<<>>, _Index, _Table) -> ok;
+load_vector_index_aux(<<SPtr:32/little, EPtr:32/little, VectorIndexBin/binary>>, Index, Table) ->
+    ets:insert(Table, {Index, SPtr, EPtr}),
+    load_vector_index_aux(VectorIndexBin, Index + 1, Table).
+
+search_ip(IoDevice, Ip, #state{version = Version}) ->
+    SegSize = ip2region_xdb:segment_index_size(Version),
+    VectorTable = ip2region_xdb:vector_index_table(Version),
+    SegmentTable = ip2region_xdb:segment_index_table(Version),
+    <<A:8, B:8, _/binary>> = Ip,
+    VectorIdx = A * ?XDB_VECTOR_COLS + B,
+    [{_, SPtr, EPtr}] = ets:lookup(VectorTable, VectorIdx),
+    search_ip(IoDevice, Ip, SPtr, EPtr, 0,
+              (EPtr - SPtr) div SegSize, SegSize, Version, SegmentTable).
+
+search_ip(IoDevice, Ip, SPtr, EPtr, Low, High, SegSize, Version, SegmentTable) when Low =< High ->
     Middle = (Low + High) bsr 1,
-    SPtr2 = SPtr + Middle * ?XDB_SEGMENT_INDEX_SIZE,
-    {SIp, EIp, DataLen, DataPtr} = read_segement_index(IoDevice, SPtr2),
-    if 
-        IntIp < SIp ->
-            search_ip(IoDevice, IntIp, SPtr, EPtr, Low, Middle - 1);
-        IntIp > EIp ->
-            search_ip(IoDevice, IntIp, SPtr, EPtr, Middle + 1, High);
-        true ->
+    SPtr2 = SPtr + Middle * SegSize,
+    {SIp, EIp, DataLen, DataPtr} = read_segment_index(IoDevice, SPtr2, SegSize, SegmentTable),
+    case ip_in_range(Ip, SIp, EIp, Version) of
+        below ->
+            search_ip(IoDevice, Ip, SPtr, EPtr, Low, Middle - 1, SegSize, Version, SegmentTable);
+        above ->
+            search_ip(IoDevice, Ip, SPtr, EPtr, Middle + 1, High, SegSize, Version, SegmentTable);
+        inside ->
             {ok, DataBin} = read_file(IoDevice, DataPtr, DataLen),
             unicode:characters_to_nfc_list(DataBin)
     end;
-search_ip(_IoDevice, _IntIp, _SPtr, _EPtr, _Low, _High)  ->
+search_ip(_IoDevice, _Ip, _SPtr, _EPtr, _Low, _High, _SegSize, _Version, _SegmentTable) ->
     {error, unknown}.
 
-read_file(IoDevice, Position, DataLength) ->
-    file:position(IoDevice, {bof, Position}),
-    file:read(IoDevice, DataLength).
+ip_in_range(Ip, SIp, EIp, ipv4) ->
+    <<InputInt:32>> = Ip,
+    if
+        InputInt < SIp -> below;
+        InputInt > EIp -> above;
+        true -> inside
+    end;
+ip_in_range(Ip, SIp, EIp, ipv6) ->
+    if
+        Ip < SIp -> below;
+        Ip > EIp -> above;
+        true -> inside
+    end.
 
-read_segement_index(IoDevice, SPtr) ->
-    case ets:lookup(?XDB_SEGMENT_INDEX, SPtr) of
+read_file(IoDevice, Position, DataLength) ->
+    file:pread(IoDevice, Position, DataLength).
+
+read_segment_index(IoDevice, SPtr, SegSize, SegmentTable) ->
+    case ets:lookup(SegmentTable, SPtr) of
         [{_SPtr, SIp, EIp, DataLen, DataPtr}] ->
             {SIp, EIp, DataLen, DataPtr};
         _ ->
-            {ok, <<SIp:32/little, EIp:32/little, DataLen:16/little, DataPtr:32/little>>} = 
-	            read_file(IoDevice, SPtr, ?XDB_SEGMENT_INDEX_SIZE),
-            ets:insert_new(?XDB_SEGMENT_INDEX, {SPtr, SIp, EIp, DataLen, DataPtr}),
+            {ok, Bin} = read_file(IoDevice, SPtr, SegSize),
+            {SIp, EIp, DataLen, DataPtr} = decode_segment_index(Bin, SegSize),
+            ets:insert_new(SegmentTable, {SPtr, SIp, EIp, DataLen, DataPtr}),
             {SIp, EIp, DataLen, DataPtr}
-    end.
\ No newline at end of file
+    end.
+
+decode_segment_index(Bin, ?XDB_SEGMENT_INDEX_SIZE_V4) ->
+    <<SIp:32/little, EIp:32/little, DataLen:16/little, DataPtr:32/little>> = Bin,
+    {SIp, EIp, DataLen, DataPtr};
+decode_segment_index(Bin, ?XDB_SEGMENT_INDEX_SIZE_V6) ->
+    <<SIp:16/binary, EIp:16/binary, DataLen:16/little, DataPtr:32/little>> = Bin,
+    {SIp, EIp, DataLen, DataPtr}.
diff --git a/binding/erlang/src/ip2region_xdb.erl b/binding/erlang/src/ip2region_xdb.erl
new file mode 100644
index 0000000..383f318
--- /dev/null
+++ b/binding/erlang/src/ip2region_xdb.erl
@@ -0,0 +1,60 @@
+%%%-------------------------------------------------------------------
+%% Copyright 2022 The Ip2Region Authors. All rights reserved.
+%% Use of this source code is governed by a Apache2.0-style
+%% license that can be found in the LICENSE file.
+%%
+%% @doc
+%% ip2region xdb binary format helpers.
+%% @end
+%%%-------------------------------------------------------------------
+-module(ip2region_xdb).
+
+-export([parse_header/1]).
+-export([header_version/1, header_index_policy/1, header_created_at/1,
+         header_start_index_ptr/1, header_end_index_ptr/1,
+         header_ip_version/1, header_runtime_ptr_bytes/1]).
+-export([segment_index_size/1]).
+-export([vector_index_table/1, segment_index_table/1, cache_table/1]).
+
+-include("ip2region.hrl").
+
+-spec parse_header(binary()) -> {ok, #xdb_header{}} | {error, invalid_header}.
+parse_header(Bin) when is_binary(Bin), byte_size(Bin) >= 20 ->
+    <<Version:16/little, IndexPolicy:16/little, CreatedAt:32/little,
+      StartIndexPtr:32/little, EndIndexPtr:32/little,
+      IpVersion:16/little, RuntimePtrBytes:16/little, _/binary>> = Bin,
+    {ok, #xdb_header{
+        version = Version,
+        index_policy = IndexPolicy,
+        created_at = CreatedAt,
+        start_index_ptr = StartIndexPtr,
+        end_index_ptr = EndIndexPtr,
+        ip_version = IpVersion,
+        runtime_ptr_bytes = RuntimePtrBytes
+    }};
+parse_header(_) ->
+    {error, invalid_header}.
+
+header_version(#xdb_header{version = V}) -> V.
+header_index_policy(#xdb_header{index_policy = P}) -> P.
+header_created_at(#xdb_header{created_at = T}) -> T.
+header_start_index_ptr(#xdb_header{start_index_ptr = P}) -> P.
+header_end_index_ptr(#xdb_header{end_index_ptr = P}) -> P.
+header_ip_version(#xdb_header{ip_version = V}) -> V.
+header_runtime_ptr_bytes(#xdb_header{runtime_ptr_bytes = B}) -> B.
+
+-spec segment_index_size(ipv4 | ipv6) -> pos_integer().
+segment_index_size(ipv4) -> ?XDB_SEGMENT_INDEX_SIZE_V4;
+segment_index_size(ipv6) -> ?XDB_SEGMENT_INDEX_SIZE_V6.
+
+-spec vector_index_table(ipv4 | ipv6) -> atom().
+vector_index_table(ipv4) -> ?XDB_VECTOR_INDEX_V4;
+vector_index_table(ipv6) -> ?XDB_VECTOR_INDEX_V6.
+
+-spec segment_index_table(ipv4 | ipv6) -> atom().
+segment_index_table(ipv4) -> ?XDB_SEGMENT_INDEX_V4;
+segment_index_table(ipv6) -> ?XDB_SEGMENT_INDEX_V6.
+
+-spec cache_table(ipv4 | ipv6) -> atom().
+cache_table(ipv4) -> ?IP2REGION_CACHE_V4;
+cache_table(ipv6) -> ?IP2REGION_CACHE_V6.
diff --git a/binding/erlang/src/xdb.erl b/binding/erlang/src/xdb.erl
index 2b98ac6..66b1c0d 100644
--- a/binding/erlang/src/xdb.erl
+++ b/binding/erlang/src/xdb.erl
@@ -1,11 +1,10 @@
-
 %%%-------------------------------------------------------------------
 %% Copyright 2022 The Ip2Region Authors. All rights reserved.
 %% Use of this source code is governed by a Apache2.0-style
 %% license that can be found in the LICENSE file.
-%% 
-%% @doc 
-%% ip2region xdb client search api
+%%
+%% @doc
+%% ip2region xdb client search api with IPv4/IPv6 auto-routing.
 %% @end
 %%%-------------------------------------------------------------------
 -module(xdb).
@@ -13,20 +12,37 @@
 
 -export([search/1]).
 
--spec search(Ip :: tuple() | list() | binary()) -> Result :: binary | {error, Reason::atom()}.
-search(Ip) when is_integer(Ip); is_list(Ip); is_tuple(Ip); is_binary(Ip) ->
-    case ip2region_util:ipv4_to_n(Ip) of
-    IntIp when is_integer(IntIp) ->
-        case ets:lookup(?IP2REGION_CACHE, IntIp) of
-        [{_IntIp, Region}] -> Region;
-        _ ->
-            Worker = poolboy:checkout(?IP2REGION_POOL, true, infinity),
-            try
-                ip2region_worker:search(Worker, IntIp)
-            after
-                poolboy:checkin(?IP2REGION_POOL, Worker)
-            end
-        end;
-    Ret ->
-        Ret
+-spec search(Ip :: tuple() | list() | binary() | integer()) ->
+    Result :: list() | {error, term()}.
+search(Ip) ->
+    case ip2region_util:ip_to_bytes(Ip) of
+        {ok, ipv4, IpBin} ->
+            do_search(?IP2REGION_POOL_V4, ipv4, IpBin);
+        {ok, ipv6, IpBin} ->
+            do_search(?IP2REGION_POOL_V6, ipv6, IpBin);
+        Ret ->
+            Ret
+    end.
+
+do_search(PoolName, Version, IpBin) ->
+    CacheTable = ip2region_xdb:cache_table(Version),
+    case ets:lookup(CacheTable, IpBin) of
+        [{_, Region}] -> Region;
+        _ ->
+            case whereis(PoolName) of
+                undefined ->
+                    {error, pool_not_configured};
+                _ ->
+                    Worker = poolboy:checkout(PoolName, true, infinity),
+                    try
+                        case ip2region_worker:search(Worker, IpBin) of
+                            {error, _} = Err -> Err;
+                            Region ->
+                                ets:insert(CacheTable, {IpBin, Region}),
+                                Region
+                        end
+                    after
+                        poolboy:checkin(PoolName, Worker)
+                    end
+            end
     end.
diff --git a/binding/erlang/src/xdb_benchmark.erl b/binding/erlang/src/xdb_benchmark.erl
index e52801c..36d94d8 100644
--- a/binding/erlang/src/xdb_benchmark.erl
+++ b/binding/erlang/src/xdb_benchmark.erl
@@ -11,29 +11,84 @@
 -export([main/1]).
 
 main(DataFile) ->
-	application:ensure_started(ip2region),
+    %% Keep benchmark output clean while still surfacing real errors.
+    _ = logger:set_handler_config(default, level, error),
+    _ = logger:set_primary_config(level, error),
+    {ok, _} = application:ensure_all_started(ip2region),
     show_hw_sw_info(),
     IpList = load_test_data(DataFile),
     run(IpList).
 
 show_hw_sw_info() ->
-    io:format("CPU info:~n", []),
-    io:format("~s", [os:cmd("egrep '^model name' /proc/cpuinfo | head -1")]),
-    io:format("~s", [os:cmd("egrep '^cache' /proc/cpuinfo | head -1")]),
-    io:format("~s", [os:cmd("egrep '^cpu MHz' /proc/cpuinfo | head -1")]),
-    io:format("~s", [os:cmd("egrep '^bogomips' /proc/cpuinfo | head -1")]),
-    io:format("cores/threads   : ~s~n", [os:cmd("egrep -c '^processor' /proc/cpuinfo")]),
-    io:format("Erlang info:~n", []),
-    io:format("system_version:~s", [erlang:system_info(system_version)]),
+    {Model, Clock, Cores, Threads} = cpu_info(),
+    io:format("~nSystem:~n", []),
+    io:format("  CPU    : ~s", [Model]),
+    case Clock of
+        "" -> io:format("~n", []);
+        _ -> io:format(" @ ~s~n", [Clock])
+    end,
+    io:format("  Cores  : ~s cores / ~s threads~n", [Cores, Threads]),
+    io:format("  Erlang : ~s~n", [string:trim(erlang:system_info(system_version))]),
     ok.
 
+cpu_info() ->
+    case os:type() of
+        {unix, darwin} ->
+            Model = sysctl("machdep.cpu.brand_string"),
+            Clock = first_non_empty([
+                format_clock(sysctl("hw.cpufrequency")),
+                format_clock(sysctl("hw.perflevel0.frequency")),
+                format_clock(sysctl("hw.perflevel1.frequency"))
+            ]),
+            Cores = sysctl("hw.physicalcpu"),
+            Threads = sysctl("hw.logicalcpu"),
+            {Model, Clock, Cores, Threads};
+        {unix, linux} ->
+            Model = linux_cpu_field("model name"),
+            Clock = format_clock_mhz(linux_cpu_field("cpu MHz")),
+            Cores = string:trim(os:cmd("grep -c '^processor' /proc/cpuinfo 2>/dev/null")),
+            Threads = Cores,
+            {Model, Clock, Cores, Threads};
+        _ ->
+            {"unknown", "", "?", "?"}
+    end.
+
+sysctl(Key) ->
+    string:trim(os:cmd("sysctl -n " ++ Key ++ " 2>/dev/null")).
+
+linux_cpu_field(Key) ->
+    Cmd = "grep -m1 '^" ++ Key ++ "' /proc/cpuinfo 2>/dev/null | cut -d: -f2- | sed 's/^ *//'",
+    string:trim(os:cmd(Cmd)).
+
+first_non_empty(["" | Rest]) -> first_non_empty(Rest);
+first_non_empty([Val | _]) -> Val;
+first_non_empty([]) -> "".
+
+format_clock(HzStr) ->
+    case string:to_integer(string:trim(HzStr)) of
+        {ok, Hz, _} when Hz > 1000000000 ->
+            lists:flatten(io_lib:format("~.2f GHz", [Hz / 1000000000]));
+        {ok, Hz, _} when Hz > 1000000 ->
+            lists:flatten(io_lib:format("~.2f MHz", [Hz / 1000000]));
+        _ ->
+            ""
+    end.
+
+format_clock_mhz(MhzStr) ->
+    case string:to_float(string:trim(MhzStr)) of
+        {ok, Mhz, _} ->
+            lists:flatten(io_lib:format("~.3f GHz", [Mhz / 1000]));
+        _ ->
+            ""
+    end.
+
 load_test_data(DataFile) ->
     {ok, Fd} = file:open(DataFile, [read]),
     T0 = os:timestamp(),
     IpList = load_test_data(Fd, []),
     T1 = os:timestamp(),
     Sec = timer:now_diff(T1, T0) / 1000000,
-    io:format("load test data use ~ps~n", [Sec]),
+    io:format("  Loaded : ~p IPs in ~.3f s~n", [length(IpList), Sec]),
     IpList.
 
 load_test_data(Fd, IpList) ->
@@ -46,30 +101,30 @@ load_test_data(Fd, IpList) ->
                 load_test_data(Fd, IpList)
             end;
         _ ->
-			file:close(Fd),
+            file:close(Fd),
             IpList
     end.
 
 run(IpList) ->
     garbage_collect(),
-    io:format("~nstart run benchmark tests~n", []),
-    io:format("~nsearch from file:~n", []),
-    run_test(IpList),
-    io:format("~nsearch from cache:~n", []),
-    run_test(IpList),
-    io:format("~nbenchmark test finish~n", []).
+    io:format("~nBenchmarks:~n", []),
+    run_test("cold", IpList),
+    run_test("warm", IpList),
+    io:format("~nDone.~n", []).
 
-run_test(IpList) ->
+run_test(Label, IpList) ->
     T0 = os:timestamp(),
     run_test_aux(IpList),
     T1 = os:timestamp(),
     Sec = timer:now_diff(T1, T0) / 1000000,
-    IpCount = length(IpList),
-    io:format("ip count:~p,~ntotal time: ~ps,~nsearch ~p times per second,~nuse ~p micro second per search~n", 
-        [IpCount, Sec, IpCount / Sec, Sec * 1000000/IpCount]).
+    Count = length(IpList),
+    Qps = Count / Sec,
+    MsOp = Sec * 1000 / Count,
+    UsOp = Sec * 1000000 / Count,
+    io:format("  ~-8s  total=~7.3fs  count=~7w  qps=~12.2f  avg=~9.6f ms/op (~6.3f us/op)~n",
+              [Label, Sec, Count, Qps, MsOp, UsOp]).
 
 run_test_aux([]) -> ok;
 run_test_aux([Ip | Tail]) ->
     xdb:search(Ip),
     run_test_aux(Tail).
-
diff --git a/binding/erlang/test/ip2region_sup_test.erl b/binding/erlang/test/ip2region_sup_test.erl
new file mode 100644
index 0000000..9c86e12
--- /dev/null
+++ b/binding/erlang/test/ip2region_sup_test.erl
@@ -0,0 +1,8 @@
+-module(ip2region_sup_test).
+-include_lib("eunit/include/eunit.hrl").
+-include("ip2region.hrl").
+
+pools_started_test() ->
+    {ok, _} = ip2region_test_util:start_app(),
+    ?assert(is_pid(whereis(?IP2REGION_POOL_V4))),
+    ?assert(is_pid(whereis(?IP2REGION_POOL_V6))).
diff --git a/binding/erlang/test/ip2region_test_util.erl b/binding/erlang/test/ip2region_test_util.erl
new file mode 100644
index 0000000..4e7417b
--- /dev/null
+++ b/binding/erlang/test/ip2region_test_util.erl
@@ -0,0 +1,51 @@
+-module(ip2region_test_util).
+
+-export([
+    repo_root/0,
+    v6_xdb_path/0,
+    default_db_config/0,
+    reset_app/0,
+    load_app/0,
+    set_db_config/1,
+    start_app/0,
+    start_app/1,
+    stop_app/0
+]).
+
+repo_root() ->
+    TestDir = filename:dirname(?FILE),
+    ErlangDir = filename:dirname(TestDir),
+    BindingDir = filename:dirname(ErlangDir),
+    filename:dirname(BindingDir).
+
+v6_xdb_path() ->
+    filename:join([repo_root(), "data", "ip2region_v6.xdb"]).
+
+default_db_config() ->
+    [
+        {ipv4, "ip2region.xdb"},
+        {ipv6, v6_xdb_path()}
+    ].
+
+reset_app() ->
+    try application:stop(ip2region) catch _:_ -> ok end,
+    try application:unload(ip2region) catch _:_ -> ok end,
+    ok.
+
+load_app() ->
+    ok = application:load(ip2region).
+
+set_db_config(Config) ->
+    ok = application:set_env(ip2region, db, Config).
+
+start_app() ->
+    start_app(default_db_config()).
+
+start_app(Config) ->
+    reset_app(),
+    load_app(),
+    set_db_config(Config),
+    application:ensure_all_started(ip2region).
+
+stop_app() ->
+    application:stop(ip2region).
diff --git a/binding/erlang/test/ip2region_util_test.erl b/binding/erlang/test/ip2region_util_test.erl
new file mode 100644
index 0000000..85880de
--- /dev/null
+++ b/binding/erlang/test/ip2region_util_test.erl
@@ -0,0 +1,66 @@
+-module(ip2region_util_test).
+-include_lib("eunit/include/eunit.hrl").
+
+ipv4_inputs_test_() ->
+    [
+        ?_assertEqual({ok, ipv4, <<1,0,8,0>>}, ip2region_util:ip_to_bytes("1.0.8.0")),
+        ?_assertEqual({ok, ipv4, <<1,0,8,0>>}, ip2region_util:ip_to_bytes(<<"1.0.8.0">>)),
+        ?_assertEqual({ok, ipv4, <<1,0,8,0>>}, ip2region_util:ip_to_bytes({1,0,8,0})),
+        ?_assertEqual({ok, ipv4, <<1,0,8,0>>}, ip2region_util:ip_to_bytes(16779264)),
+        ?_assertEqual(ipv4, ip2region_util:ip_version("1.0.8.0")),
+        ?_assertEqual(ipv4, ip2region_util:ip_version({1,0,8,0}))
+    ].
+
+ipv6_inputs_test_() ->
+    [
+        ?_assertEqual({ok, ipv6, <<0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1>>},
+                      ip2region_util:ip_to_bytes("::1")),
+        ?_assertEqual({ok, ipv6, <<0,0,0,0,0,0,0,0,0,0,255,255,1,0,8,0>>},
+                      ip2region_util:ip_to_bytes("::ffff:1.0.8.0")),
+        ?_assertEqual({ok, ipv6, <<0,0,0,0,0,0,0,0,0,0,255,255,1,0,8,0>>},
+                      ip2region_util:ip_to_bytes(<<"::ffff:1.0.8.0">>)),
+        ?_assertEqual({ok, ipv6, <<0,0,0,0,0,0,0,0,0,0,255,255,1,0,8,0>>},
+                      ip2region_util:ip_to_bytes({0,0,0,0,0,65535,256,2048})),
+        ?_assertEqual(ipv6, ip2region_util:ip_version("::1")),
+        ?_assertEqual(ipv6, ip2region_util:ip_version({0,0,0,0,0,0,0,1}))
+    ].
+
+invalid_inputs_test_() ->
+    [
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_to_bytes("xxx.0.8.0")),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_to_bytes("::ggg")),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_to_bytes({1,2,3})),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_to_bytes({1,2,3,4,5,6,7})),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_to_bytes(atom)),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_to_bytes(-1)),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_to_bytes(16#100000000)),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_to_bytes({256, 0, 0, 1})),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_to_bytes({-1, 0, 0, 0})),
+        ?_assertEqual({error, bad_ip_format},
+                      ip2region_util:ip_to_bytes({0, 0, 0, 0, 0, 0, 0, 65536})),
+        ?_assertEqual({error, bad_ip_format},
+                      ip2region_util:ip_to_bytes({0, 0, 0, 0, 0, 0, 0, -1})),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ipv4_to_n(-1)),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ipv4_to_n(16#100000000)),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ipv4_to_n({256, 0, 0, 1}))
+    ].
+
+ip_version_test_() ->
+    [
+        ?_assertEqual(ipv4, ip2region_util:ip_version(<<"1.0.8.0">>)),
+        ?_assertEqual(ipv6, ip2region_util:ip_version(<<"::1">>)),
+        ?_assertEqual(ipv4, ip2region_util:ip_version(16779264 + 1)),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_version("::ggg")),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_version({1,2,3})),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_version({256,0,0,1})),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_version({0,0,0,0,0,0,0,65536})),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_version(16#100000000))
+    ].
+
+legacy_ipv4_to_n_test_() ->
+    [
+        ?_assertEqual(16779264, ip2region_util:ipv4_to_n("1.0.8.0")),
+        ?_assertEqual(16779264, ip2region_util:ipv4_to_n(<<"1.0.8.0">>)),
+        ?_assertEqual(16779264, ip2region_util:ipv4_to_n({1,0,8,0})),
+        ?_assertEqual(16779264, ip2region_util:ipv4_to_n(16779264))
+    ].
diff --git a/binding/erlang/test/ip2region_worker_test.erl b/binding/erlang/test/ip2region_worker_test.erl
new file mode 100644
index 0000000..5a2417c
--- /dev/null
+++ b/binding/erlang/test/ip2region_worker_test.erl
@@ -0,0 +1,13 @@
+-module(ip2region_worker_test).
+-include_lib("eunit/include/eunit.hrl").
+-include("ip2region.hrl").
+
+worker_search_v4_binary_test() ->
+    ip2region_sup:create_table(),
+    {ok, Pid} = ip2region_worker:start_link([{xdb_file, "ip2region.xdb"}]),
+    try
+        Region = ip2region_worker:search(Pid, <<1,0,8,0>>),
+        ?assert(is_list(Region))
+    after
+        ip2region_worker:stop(Pid)
+    end.
diff --git a/binding/erlang/test/ip2region_xdb_test.erl b/binding/erlang/test/ip2region_xdb_test.erl
new file mode 100644
index 0000000..cf3084c
--- /dev/null
+++ b/binding/erlang/test/ip2region_xdb_test.erl
@@ -0,0 +1,43 @@
+-module(ip2region_xdb_test).
+
+-include_lib("eunit/include/eunit.hrl").
+-include("ip2region.hrl").
+
+valid_v4_header_test() ->
+    HeaderBin = <<2:16/little, 1:16/little, 0:32/little,
+                  256:32/little, 1024:32/little,
+                  ?IP_VERSION_4:16/little, 4:16/little>>,
+    {ok, Header} = ip2region_xdb:parse_header(HeaderBin),
+    ?assertEqual(2, ip2region_xdb:header_version(Header)),
+    ?assertEqual(1, ip2region_xdb:header_index_policy(Header)),
+    ?assertEqual(256, ip2region_xdb:header_start_index_ptr(Header)),
+    ?assertEqual(1024, ip2region_xdb:header_end_index_ptr(Header)),
+    ?assertEqual(?IP_VERSION_4, ip2region_xdb:header_ip_version(Header)),
+    ?assertEqual(4, ip2region_xdb:header_runtime_ptr_bytes(Header)).
+
+valid_v6_header_test() ->
+    HeaderBin = <<3:16/little, 1:16/little, 0:32/little,
+                  256:32/little, 1024:32/little,
+                  ?IP_VERSION_6:16/little, 4:16/little>>,
+    {ok, Header} = ip2region_xdb:parse_header(HeaderBin),
+    ?assertEqual(3, ip2region_xdb:header_version(Header)),
+    ?assertEqual(?IP_VERSION_6, ip2region_xdb:header_ip_version(Header)).
+
+invalid_header_test() ->
+    ?assertEqual({error, invalid_header}, ip2region_xdb:parse_header(<<0:128>>)).
+
+table_helpers_test_() ->
+    [
+        ?_assertEqual(?XDB_VECTOR_INDEX_V4, ip2region_xdb:vector_index_table(ipv4)),
+        ?_assertEqual(?XDB_VECTOR_INDEX_V6, ip2region_xdb:vector_index_table(ipv6)),
+        ?_assertEqual(?XDB_SEGMENT_INDEX_V4, ip2region_xdb:segment_index_table(ipv4)),
+        ?_assertEqual(?XDB_SEGMENT_INDEX_V6, ip2region_xdb:segment_index_table(ipv6)),
+        ?_assertEqual(?IP2REGION_CACHE_V4, ip2region_xdb:cache_table(ipv4)),
+        ?_assertEqual(?IP2REGION_CACHE_V6, ip2region_xdb:cache_table(ipv6))
+    ].
+
+segment_index_size_test_() ->
+    [
+        ?_assertEqual(14, ip2region_xdb:segment_index_size(ipv4)),
+        ?_assertEqual(38, ip2region_xdb:segment_index_size(ipv6))
+    ].
diff --git a/binding/erlang/test/xdb_test.erl b/binding/erlang/test/xdb_test.erl
index 85adcac..5388f6e 100644
--- a/binding/erlang/test/xdb_test.erl
+++ b/binding/erlang/test/xdb_test.erl
@@ -2,9 +2,11 @@
 
 -include_lib("eunit/include/eunit.hrl").
 
+-define(IPV6_RESULT, "United States|Florida|Miami|Google LLC|US").
+
 search_test_() ->
-    application:ensure_started(ip2region),
-    A = "中国|0|广东省|广州市|电信",
+    {ok, _} = ip2region_test_util:start_app(),
+    A = "中国|广东省|广州市|中国电信|CN",
     Region0 = xdb:search("1.0.8.0"),
     Region1 = xdb:search(<<"1.0.8.0">>),
     Region2 = xdb:search({1,0,8,0}),
@@ -14,5 +16,39 @@ search_test_() ->
         ?_assert(A =:= Region1),
         ?_assert(A =:= Region2),
         ?_assert({error, bad_ip_format} =:= Region3)
+    ].
 
-    ].
\ No newline at end of file
+ipv6_search_test_() ->
+    {ok, _} = ip2region_test_util:start_app(),
+    [
+        ?_assert(?IPV6_RESULT =:= xdb:search("2001:4860:4860::8888")),
+        ?_assert(?IPV6_RESULT =:= xdb:search(<<"2001:4860:4860::8888">>)),
+        ?_assert(?IPV6_RESULT =:= xdb:search({8193, 18528, 18528, 0, 0, 0, 0, 34952}))
+    ].
+
+invalid_search_test_() ->
+    {ok, _} = ip2region_test_util:start_app(),
+    [
+        ?_assertEqual({error, bad_ip_format}, xdb:search("xxx.0.8.0")),
+        ?_assertEqual({error, bad_ip_format}, xdb:search("::ggg")),
+        ?_assertEqual({error, bad_ip_format}, xdb:search({1,2,3}))
+    ].
+
+ipv6_pool_not_configured_test() ->
+    {ok, _} = ip2region_test_util:start_app([{ipv4, "ip2region.xdb"}]),
+    ?assertEqual({error, pool_not_configured}, xdb:search("2001:4860:4860::8888")).
+
+xdb_version_mismatch_test() ->
+    {ok, _} = ip2region_test_util:start_app(),
+    V4File = filename:join([
+        ip2region_test_util:repo_root(), "binding", "erlang", "priv", "ip2region.xdb"
+    ]),
+    error_logger:tty(false),
+    try
+        ?assertEqual(
+            {error, {xdb_version_mismatch, ipv6, ipv4}},
+            ip2region_worker:start([{xdb_file, V4File}, {expected_version, ipv6}])
+        )
+    after
+        error_logger:tty(true)
+    end.