add database-aware MySQL pooling

scripts/check_unit_wasm.py

@@ -160,7 +160,7 @@ def defined_symbols(path: Path, llvm_nm: str) -> list[str]:
 def main() -> int:
     ap = argparse.ArgumentParser()
     ap.add_argument("wasm", type=Path)
-    ap.add_argument("--abi-version", default="6")
+    ap.add_argument("--abi-version", default="7")
     ap.add_argument("--llvm-nm", default=None)
     ap.add_argument("--verbose", action="store_true")
     args = ap.parse_args()

scripts/compile_wasm_unit

@@ -11,7 +11,7 @@ PP_FN="$4"
 WASM_FN="$5"
 
 SDK=${WASI_SDK:-/opt/wasi-sdk}
-ABI_VERSION=${UCE_UNIT_ABI_VERSION:-6}
+ABI_VERSION=${UCE_UNIT_ABI_VERSION:-7}
 ROOT=$(pwd)
 OBJ_FN="$DEST_DIR/$PP_FN.wasm.o"
 ABI_TMP="$DEST_DIR/$PP_FN.uce-abi.txt"

scripts/test_mysql_persistent_pool.sh

@@ -18,10 +18,11 @@ cache_dir=""
 http_host="${UCE_TEST_HTTP_HOST:-uce.openfu.com}"
 test_user="uce_pool_$$"
 test_database="uce_pool_$$"
+test_database_other="uce_pool_other_$$"
 test_password=$(printf '%s' "$test_name-$(date +%s%N)" | sha256sum | cut -c1-32)
 
 cleanup() {
-	mariadb -e "DROP DATABASE IF EXISTS \`$test_database\`; DROP USER IF EXISTS '$test_user'@'127.0.0.1'" >/dev/null 2>&1 || true
+	mariadb -e "DROP DATABASE IF EXISTS \`$test_database\`; DROP DATABASE IF EXISTS \`$test_database_other\`; DROP USER IF EXISTS '$test_user'@'127.0.0.1'" >/dev/null 2>&1 || true
 	rm -rf "$source_dir"
 	if [[ -n "$cache_dir" ]]; then
 		rm -rf "$cache_dir"
@@ -30,14 +31,21 @@ cleanup() {
 trap cleanup EXIT
 mkdir -p "$source_dir"
 cache_dir="$bin_directory$(realpath "$source_dir")"
-mariadb -e "DROP DATABASE IF EXISTS \`$test_database\`; DROP USER IF EXISTS '$test_user'@'127.0.0.1'; CREATE DATABASE \`$test_database\`; CREATE USER '$test_user'@'127.0.0.1' IDENTIFIED BY '$test_password'; GRANT ALL ON \`$test_database\`.* TO '$test_user'@'127.0.0.1'"
+mariadb -e "DROP DATABASE IF EXISTS \`$test_database\`; DROP DATABASE IF EXISTS \`$test_database_other\`; DROP USER IF EXISTS '$test_user'@'127.0.0.1'; CREATE DATABASE \`$test_database\`; CREATE DATABASE \`$test_database_other\`; CREATE USER '$test_user'@'127.0.0.1' IDENTIFIED BY '$test_password'; GRANT ALL ON \`$test_database\`.* TO '$test_user'@'127.0.0.1'; GRANT ALL ON \`$test_database_other\`.* TO '$test_user'@'127.0.0.1'; CREATE TABLE \`$test_database\`.pool_identity (label VARCHAR(16) NOT NULL); INSERT INTO \`$test_database\`.pool_identity VALUES ('primary'); CREATE TABLE \`$test_database_other\`.pool_identity (label VARCHAR(16) NOT NULL); INSERT INTO \`$test_database_other\`.pool_identity VALUES ('other')"
 
 printf '%s\n' \
 	'RENDER(Request& context)' \
 	'{' \
-	"  MySQL* db = mysql_connect(\"127.0.0.1\", \"$test_user\", \"$test_password\");" \
+	"  MySQL* db = mysql_connect(\"127.0.0.1\", \"$test_user\", \"$test_password\", \"$test_database\");" \
-	'  if(db == 0 || mysql_error(db) != "") { context.set_status(500, "MySQL connect failed"); print("connect-failed"); return; }' \
+	"  MySQL* other = mysql_connect(\"127.0.0.1\", \"$test_user\", \"$test_password\", \"$test_database_other\");" \
-	"  mysql_query(db, \"USE \\\`$test_database\\\`\");" \
+	"  MySQL* unselected = mysql_connect(\"127.0.0.1\", \"$test_user\", \"$test_password\");" \
+	'  if(db == 0 || other == 0 || unselected == 0 || !mysql_connected(db) || !mysql_connected(other) || !mysql_connected(unselected)) { context.set_status(500, "MySQL connect failed"); print("connect-failed"); return; }' \
+	'  String primary_database, primary_label, other_database, other_label;' \
+	'  mysql_query(db, "SELECT DATABASE() AS db, label FROM pool_identity").each([&](DValue row, String key) { primary_database = row["db"].to_string(); primary_label = row["label"].to_string(); });' \
+	'  mysql_query(other, "SELECT DATABASE() AS db, label FROM pool_identity").each([&](DValue row, String key) { other_database = row["db"].to_string(); other_label = row["label"].to_string(); });' \
+	'  String unselected_database;' \
+	'  mysql_query(unselected, "SELECT DATABASE() AS db").each([&](DValue row, String key) { unselected_database = row["db"].to_string(); });' \
+	"  bool database_clean = primary_database == \"$test_database\" && primary_label == \"primary\" && other_database == \"$test_database_other\" && other_label == \"other\" && unselected_database == \"\";" \
 	'  DValue marker_rows = mysql_query(db, "SELECT @uce_pool_marker AS marker");' \
 	'  String marker; marker_rows.each([&](DValue row, String key) { marker = row["marker"].to_string(); });' \
 	'  bool marker_clean = marker == "";' \
@@ -45,19 +53,39 @@ printf '%s\n' \
 	'  bool temp_clean = mysql_error(db) != "";' \
 	"  mysql_query(db, \"SET @uce_pool_marker='dirty'\");" \
 	'  mysql_query(db, "CREATE TEMPORARY TABLE uce_persistent_temp (id INT PRIMARY KEY)");' \
+	"  mysql_query(db, \"USE \\\`$test_database_other\\\`\");" \
+	"  mysql_query(other, \"USE \\\`$test_database\\\`\");" \
+	"  mysql_query(unselected, \"USE \\\`$test_database\\\`\");" \
 	'  DValue perf = request_perf();' \
 	'  String source;' \
-	'  perf["mysql_operations"].each([&](DValue operation, String key) { if(operation["op"].to_string() == "connect") source = operation["source"].to_string(); });' \
+	'  perf["mysql_operations"].each([&](DValue operation, String key) { if(operation["op"].to_string() == "connect" && operation["source"].to_string() == "worker") source = "worker"; });' \
-	'  print(perf["worker_pid"].to_string(), "|", source, "|", marker_clean ? "clean" : "dirty", "|", temp_clean ? "clean" : "dirty");' \
+	'  print(perf["worker_pid"].to_string(), "|", source, "|", marker_clean ? "clean" : "dirty", "|", temp_clean ? "clean" : "dirty", "|", database_clean ? "clean" : "dirty");' \
+	'  mysql_disconnect(unselected);' \
+	'  mysql_disconnect(other);' \
 	'  mysql_disconnect(db);' \
 	'}' >"$source_dir/test.uce"
 
+printf '%s\n' \
+	'RENDER(Request& context)' \
+	'{' \
+	"  MySQL* db = mysql_connect(\"127.0.0.1\", \"$test_user\", \"$test_password\", \"${test_database}_missing\");" \
+	'  String error = mysql_error(db);' \
+	'  print(!mysql_connected(db) && error != "" ? "database-selection-failed" : "database-selection-was-ignored");' \
+	'  mysql_disconnect(db);' \
+	'}' >"$source_dir/failure.uce"
+
+failure=$(curl -fsS --max-time 10 -H "Host: $http_host" "http://127.0.0.1/$test_name/failure.uce")
+if [[ "$failure" != "database-selection-failed" ]]; then
+	echo "Unknown initial database did not surface a connection failure: $failure" >&2
+	exit 1
+fi
+
 reused=0
 for _ in $(seq 1 160); do
 	output=$(curl -fsS --max-time 10 -H "Host: $http_host" "http://127.0.0.1/$test_name/test.uce")
 	if [[ "$output" == *"|worker|"* ]]; then
 		reused=$((reused + 1))
-		if [[ "$output" != *"|worker|clean|clean" ]]; then
+		if [[ "$output" != *"|worker|clean|clean|clean" ]]; then
 			echo "Persistent MySQL reuse leaked cross-request state: $output" >&2
 			exit 1
 		fi

site/doc/pages/mysql_connect.txt

@@ -1,21 +1,22 @@
 :sig
-MySQL* mysql_connect(String host = "localhost", String username = "root", String password = "")
+MySQL* mysql_connect(String host = "localhost", String username = "root", String password = "", String database = "")
 
 :params
 host : host name of the MySQL server
 username : user name
 password : password
+database : optional initial database name
 return value : pointer to the MySQL connection struct
 
 :see
 >mysql
 
 :content
-Establishes a connection to a MySQL server and returns a request-owned pointer to the connection struct. A failed connection also returns a wrapper so that `mysql_error()` can report the failure; use `mysql_connected()` before issuing optional work that requires a live server handle.
+Establishes a connection to a MySQL server and returns a request-owned pointer to the connection struct. When `database` is non-empty, the server selects it as part of connection establishment and restores it after every cross-request connection reset. A failed connection also returns a wrapper so that `mysql_error()` can report the failure; use `mysql_connected()` before issuing optional work that requires a live server handle.
 
 This connection handle is then used with helpers such as `mysql_query()`, `mysql_error()`, and `mysql_disconnect()`.
 
-MySQL handles are request-scoped framework resources. Repeated `mysql_connect()` calls with the same host and credentials reuse one server connection within the current request. Each call creates a lease and `mysql_disconnect()` releases that lease. At request cleanup UCE returns the server connection to the current worker's persistent pool, then resets it before cross-request reuse. The pool holds up to `MYSQL_PERSISTENT_POOL_SIZE` connections per worker (default 8); set the size to 0 to disable cross-request reuse. Never store a `MySQL*` in globals, sessions, or other state that can outlive the current request.
+MySQL handles are request-scoped framework resources. Repeated `mysql_connect()` calls with the same host, credentials, and database reuse one server connection within the current request. Database identity is part of both request-local and worker-persistent pool keys. Each call creates a lease and `mysql_disconnect()` releases that lease. At request cleanup UCE returns the server connection to the current worker's persistent pool, then resets it before cross-request reuse. The pool holds up to `MYSQL_PERSISTENT_POOL_SIZE` connections per worker (default 8); set the size to 0 to disable cross-request reuse. Never store a `MySQL*` in globals, sessions, or other state that can outlive the current request.
 
 :example
 MySQL* db = mysql_connect();

src/lib/compiler.cpp

@@ -16,7 +16,7 @@
 
 namespace {
 
-const u64 UCE_UNIT_ABI_VERSION = 10;
+const u64 UCE_UNIT_ABI_VERSION = 11;
 
 struct SharedUnitFilesystemState
 {

src/lib/mysql-connector.cpp

@@ -3,7 +3,7 @@
 #include <stdlib.h>
 #include "mysql-connector.h"
 
-// Same-credential mysql_connect() calls lease one request-local connection.
+// Same-target mysql_connect() calls lease one request-local connection.
 // mysql_disconnect() releases a lease; cleanup_mysql_connections() owns the
 // actual close at request end, including exception/fatal recovery paths.
 static void mysql_register_request_connection(MySQL* db)
@@ -15,8 +15,12 @@ static void mysql_register_request_connection(MySQL* db)
 		connections.push_back(db);
 }
 
-bool MySQL::connect(String host, String username, String password)
+bool MySQL::connect(String host, String username, String password, String database)
 {
+	request_host = host;
+	request_username = username;
+	request_password = password;
+	request_database = database;
 	// Register regardless of outcome: tracking is about the wrapper's
 	// lifetime, not the connection's. disconnect()/~MySQL() unregister.
 	mysql_register_request_connection(this);
@@ -32,7 +36,7 @@ bool MySQL::connect(String host, String username, String password)
 	}
 
 	if (mysql_real_connect((MYSQL*)connection, host.c_str(), username.c_str(), password.c_str(),
-	  NULL, 0, NULL, 0) == NULL)
+	  database == "" ? NULL : database.c_str(), 0, NULL, 0) == NULL)
 	{
 		auto e = mysql_error((MYSQL*)connection);
 		fprintf(stderr, "%s\n", e);
@@ -59,7 +63,17 @@ bool MySQL::connect(String host, String username, String password)
 
 bool MySQL::reset_connection()
 {
-	if(!connection || mysql_reset_connection((MYSQL*)connection) != 0)
+	if(!connection)
+		return(false);
+	MYSQL* mysql = (MYSQL*)connection;
+	String selected_database = mysql->db == NULL ? "" : mysql->db;
+	// RESET CONNECTION deliberately preserves the selected database. An
+	// unqualified lease cannot safely inherit one selected by its prior request.
+	if(request_database == "" && selected_database != "")
+		return(false);
+	if(mysql_reset_connection(mysql) != 0)
+		return(false);
+	if(request_database != "" && selected_database != request_database && mysql_select_db(mysql, request_database.c_str()) != 0)
 		return(false);
 	_preload_next_error_code = 0;
 	affected_rows = 0;

src/lib/mysql-connector.h

@@ -27,10 +27,11 @@ struct MySQL {
 	String request_host;
 	String request_username;
 	String request_password;
+	String request_database;
 
 	std::vector<MySQLFieldInfo> field_info;
 
-	bool connect(String host = "localhost", String username = "root", String password = "");
+	bool connect(String host = "localhost", String username = "root", String password = "", String database = "");
 	bool reset_connection();
 	void disconnect();
 	String error();
@@ -46,14 +47,14 @@ struct MySQL {
 
 };
 
-inline MySQL* mysql_connect(String host = "localhost", String username = "root", String password = "")
+inline MySQL* mysql_connect(String host = "localhost", String username = "root", String password = "", String database = "")
 {
 	if(context)
 	{
 		for(void* raw : context->resources.mysql_connections)
 		{
 			MySQL* db = (MySQL*)raw;
-			if(db && db->request_pooled && db->connection && db->request_host == host && db->request_username == username && db->request_password == password)
+			if(db && db->request_pooled && db->connection && db->request_host == host && db->request_username == username && db->request_password == password && db->request_database == database)
 			{
 				db->request_leases++;
 				return(db);
@@ -67,7 +68,8 @@ inline MySQL* mysql_connect(String host = "localhost", String username = "root",
 	db->request_host = host;
 	db->request_username = username;
 	db->request_password = password;
-	db->connect(host, username, password);
+	db->request_database = database;
+	db->connect(host, username, password, database);
 	return(db);
 }
 

src/wasm/core.cpp

@@ -146,13 +146,18 @@ static DValue wasm_mysql_call(DValue request)
 	return(wasm_sized_hostcall(request, uce_host_mysql));
 }
 
-bool MySQL::connect(String host, String username, String password)
+bool MySQL::connect(String host, String username, String password, String database)
 {
+	request_host = host;
+	request_username = username;
+	request_password = password;
+	request_database = database;
 	DValue request;
 	request["op"] = "connect";
 	request["host"] = host;
 	request["username"] = username;
 	request["password"] = password;
+	request["database"] = database;
 	DValue response = wasm_mysql_call(request);
 	u64 handle = response["handle"].to_u64();
 	connection = (void*)(uintptr_t)handle;
@@ -804,7 +809,7 @@ void uce_free(void* ptr)
 
 u32 uce_wasm_core_abi_version()
 {
-	return(6);
+	return(7);
 }
 
 int uce_wasm_core_init()

src/wasm/w1_smoke.cpp

@@ -254,7 +254,7 @@ int main(int argc, char** argv)
 
 	CHECK(call_i32(core, "uce_wasm_core_init") == 0, "core init failed");
 	call_i32(core, "uce_wasm_core_reset_request");
-	CHECK(call_i32(core, "uce_wasm_core_abi_version") == 6, "unexpected ABI version");
+	CHECK(call_i32(core, "uce_wasm_core_abi_version") == 7, "unexpected ABI version");
 
 	wasm_memory_t* memory = core.memory();
 	int32_t root = call_i32(core, "uce_dv_root");
@@ -302,7 +302,7 @@ int main(int argc, char** argv)
 	int32_t output_ptr = call_i32(core, "uce_wasm_output_data");
 	CHECK(read_bytes(memory, output_ptr, output_len) == out, "output plumbing mismatch");
 
-	printf("W1 core.wasm smoke: abi=6 encoded=%d output=%d\n", encoded_len, output_len);
+	printf("W1 core.wasm smoke: abi=7 encoded=%d output=%d\n", encoded_len, output_len);
 	printf("W1 EXIT CRITERION: PASS\n");
 	return(0);
 }

src/wasm/worker.cpp

@@ -968,14 +968,14 @@ public:
 			delete db;
 	}
 
-	MySQL* mysql_checkout(const String& host, const String& username, const String& password, bool& reused, bool& persistent)
+	MySQL* mysql_checkout(const String& host, const String& username, const String& password, const String& database, bool& reused, bool& persistent)
 	{
 		reused = false;
 		persistent = false;
 		for(size_t i = 0; i < mysql_persistent_pool.size(); i++)
 		{
 			MySQL* db = mysql_persistent_pool[i];
-			if(!db || !db->connection || db->request_host != host || db->request_username != username || db->request_password != password)
+			if(!db || !db->connection || db->request_host != host || db->request_username != username || db->request_password != password || db->request_database != database)
 				continue;
 			if(db->reset_connection())
 			{
@@ -1000,7 +1000,8 @@ public:
 		db->request_host = host;
 		db->request_username = username;
 		db->request_password = password;
-		if(!db->connect(host, username, password) || !db->connection)
+		db->request_database = database;
+		if(!db->connect(host, username, password, database) || !db->connection)
 			return(db);
 		if(persistent)
 		{
@@ -3705,9 +3706,10 @@ private:
 							String host = request["host"].to_string();
 							String username = request["username"].to_string();
 							String password = request["password"].to_string();
+							String database = request["database"].to_string();
 							MySQL* db = 0;
 							for(auto* pooled : self->mysql_request_pool)
-								if(pooled && pooled->connection && pooled->request_host == host && pooled->request_username == username && pooled->request_password == password)
+								if(pooled && pooled->connection && pooled->request_host == host && pooled->request_username == username && pooled->request_password == password && pooled->request_database == database)
 								{
 									db = pooled;
 									connection_source = "request";
@@ -3718,7 +3720,7 @@ private:
 							{
 								bool reused = false;
 								bool persistent = false;
-								db = self->worker.mysql_checkout(host, username, password, reused, persistent);
+								db = self->worker.mysql_checkout(host, username, password, database, reused, persistent);
 								connection_source = reused ? "worker" : "new";
 								ok = db && db->connection;
 								if(ok && db->connection)