chore: add DuckDB version info function.

storage/duckdb/docs/mariadb-duckdb-incompatibilities.md

@@ -132,7 +132,20 @@ MariaDB `MEDIUMTEXT`, `LONGTEXT`, `TEXT`, `TINYTEXT` all map to DuckDB `VARCHAR`
 
 ---
 
-## 5. DuckDB API Differences (AliSQL fork vs upstream v1.5.2)
+## 5. Table Partitioning
+
+MariaDB table partitioning is not supported for `ENGINE=DuckDB`. The handlerton declares `HTON_NO_PARTITION`, so the server rejects both partitioned table creation and conversion of an existing DuckDB table:
+
+```sql
+CREATE TABLE t (id INT) ENGINE=DuckDB PARTITION BY HASH(id);
+ALTER TABLE t PARTITION BY HASH(id);
+```
+
+Both statements fail with `ER_PARTITION_MERGE_ERROR` (`Engine cannot be used in partitioned tables`) before MariaDB creates partition child handlers or starts the `ALGORITHM=COPY` protocol.
+
+---
+
+## 6. DuckDB API Differences (AliSQL fork vs upstream v1.5.2)
 
 The AliSQL fork of DuckDB has custom extensions to the API that do not exist in upstream DuckDB:
 
@@ -145,7 +158,7 @@ The AliSQL fork of DuckDB has custom extensions to the API that do not exist in
 
 ---
 
-## 6. DuckDB Extensions
+## 7. DuckDB Extensions
 
 Loaded via `cmake/duckdb_extensions.cmake`:
 
@@ -159,7 +172,7 @@ Build flags in `cmake/duckdb.cmake`: `EXTENSION_STATIC_BUILD=1`, `DUCKDB_EXTENSI
 
 ---
 
-## 7. ABI Compatibility
+## 8. ABI Compatibility
 
 DuckDB is built as a static library (`libduckdb_bundle.a`) via `ExternalProject_Add` in `cmake/duckdb.cmake`.
 
@@ -171,7 +184,7 @@ DuckDB is built as a static library (`libduckdb_bundle.a`) via `ExternalProject_
 
 ---
 
-## 8. Potential Future Incompatibilities
+## 9. Potential Future Incompatibilities
 
 These have not been triggered yet but are likely to cause issues when more complex queries are pushed down:
 

storage/duckdb/ha_duckdb.cc

@@ -1578,7 +1578,16 @@ static struct st_mysql_sys_var *duckdb_system_variables[]= {
     MYSQL_SYSVAR(explain_output), MYSQL_SYSVAR(disabled_optimizers),
     MYSQL_SYSVAR(cross_engine_ryow), NULL};
 
+static int show_duckdb_version(MYSQL_THD, struct st_mysql_show_var *var,
+                               void *, system_status_var *, enum_var_type)
+{
+  var->type= SHOW_CHAR;
+  var->value= const_cast<char *>(duckdb::DuckDB::LibraryVersion());
+  return 0;
+}
+
 static struct st_mysql_show_var duckdb_status_variables[]= {
+    {"Duckdb_version", (char *) show_duckdb_version, SHOW_SIMPLE_FUNC},
     {"Duckdb_rows_insert", (char *) &srv_duckdb_status.duckdb_rows_insert,
      SHOW_LONGLONG},
     {"Duckdb_rows_update", (char *) &srv_duckdb_status.duckdb_rows_update,

storage/duckdb/mysql-test/duckdb/r/duckdb_monitor.result

@@ -2,6 +2,9 @@
 CREATE TABLE t1(id INT PRIMARY KEY, v VARCHAR(255)) ENGINE=duckdb;
 CREATE TABLE t2(id INT PRIMARY KEY, v VARCHAR(255)) ENGINE=duckdb;
 CREATE TABLE t3(id INT PRIMARY KEY, v VARCHAR(255)) ENGINE=innodb;
+SHOW STATUS LIKE 'Duckdb_version';
+Variable_name	Value
+Duckdb_version	v1.5.5
 #
 # 1) INSERT: rows_insert increments per row (dml_in_batch=OFF)
 #

storage/duckdb/mysql-test/duckdb/t/duckdb_monitor.test

@@ -24,6 +24,8 @@ CREATE TABLE t3(id INT PRIMARY KEY, v VARCHAR(255)) ENGINE=innodb;
 # Save baseline commit count (CREATE TABLEs cause autocommits)
 --let $base_commit = query_get_value(SHOW STATUS LIKE 'Duckdb_commit', Value, 1)
 
+SHOW STATUS LIKE 'Duckdb_version';
+
 --echo #
 --echo # 1) INSERT: rows_insert increments per row (dml_in_batch=OFF)
 --echo #