Pool reconfiguration support in Thin mode

Author: sharadraju

doc/src/api_manual/pool.rst

@@ -536,11 +536,6 @@ Pool Methods
     as the maximum number of connections in the pool, or the statement cache
     size used by connections can be changed.
 
-    .. note::
-
-        This method is only supported in node-oracledb Thick mode. See
-        :ref:`enablingthick`.
-
     Properties are optional. Unspecified properties will leave those pool
     properties unchanged. The properties are processed in two stages. After
     any size change has been processed, reconfiguration on the other
@@ -587,19 +582,19 @@ Pool Methods
           - Description
         * - ``poolAttrs``
           - Object
-          - The ``oracledb.createPool()`` properties that can be changed with ``pool.reconfigure()`` are:
+          - The following ``oracledb.createPool()`` properties can be changed with ``pool.reconfigure()`` in both Thin and Thick modes unless otherwise specified:
 
             - :ref:`enableStatistics <createpoolpoolattrsstats>`
             - :ref:`poolIncrement <createpoolpoolattrspoolincrement>`
             - :ref:`poolMax <createpoolpoolattrspoolmax>`
-            - :ref:`poolMaxPerShard <createpoolpoolattrspoolmaxpershard>`
+            - :ref:`poolMaxPerShard <createpoolpoolattrspoolmaxpershard>` in only Thick mode
             - :ref:`poolMin <createpoolpoolattrspoolmin>`
             - :ref:`poolPingInterval <createpoolpoolattrspoolpinginterval>`
             - :ref:`poolTimeout <createpoolpoolattrspooltimeout>`
             - :ref:`queueMax <createpoolpoolattrsqueuemax>`
             - :ref:`queueRequests <createpoolpoolattrsqueuerequests>`
             - :ref:`queueTimeout <createpoolpoolattrsqueuetimeout>`
-            - :ref:`sodaMetaDataCache <createpoolpoolattrssodamdcache>`
+            - :ref:`sodaMetaDataCache <createpoolpoolattrssodamdcache>` in only Thick mode
             - :ref:`stmtCacheSize <createpoolpoolattrsstmtcachesize>`
 
             A ``resetStatistics`` property can also be set to *true*. This zeros the current pool statistics, with the exception of ``queueMax`` which is set to the current queue length. Statistics are also reset when statistics recording is turned on with the ``enableStatistics`` property.

doc/src/release_notes.rst

@@ -58,6 +58,8 @@ Thin Mode Changes
     errors were raised.
     See `Issue #1652 <https://github.com/oracle/node-oracledb/issues/1652>`__.
 
+#)  Added support for pool reconfiguration.
+
 #)  Added support for Oracle Database 23c
     :ref:`Implicit Connection Pooling <implicitpool>` in DRCP and PRCP.
 

lib/thin/pool.js

@@ -386,11 +386,11 @@ class ThinPoolImpl extends PoolImpl {
   }
 
   //---------------------------------------------------------------------------
-  // _getNumConns()
+  // _getNumConnsToCreate()
   //
   // get number of connections need to be created
   //---------------------------------------------------------------------------
-  _getNumConns() {
+  _getNumConnsToCreate() {
     const usedConns = this._freeConnectionList.length + this._usedConnectionList.size;
     // less connections in the pool than poolMin? restore to poolMin
     if (usedConns < this._poolMin) {
@@ -416,11 +416,19 @@ class ThinPoolImpl extends PoolImpl {
 
     // continue until a close request is received
     while (!this._poolCloseWaiter) {
-      // get count for connections to be created
-      const numConns = this._getNumConns();
+      // eliminate connections that exceed the poolMax (this should only happen
+      // after a reconfiguration has taken place where the maximum number of
+      // connections is reduced)
+      let numToDestroy = this._poolMax - this.getConnectionsOpen();
+      while (numToDestroy > 0 && this._freeConnectionList.length > 0) {
+        const connToBeRemoved = this._freeConnectionList.shift();
+        this.eventEmitter.emit('_removePoolConnection', connToBeRemoved);
+        numToDestroy--;
+      }
 
+      const numToCreate = this._getNumConnsToCreate();
       // connection creation is going on serially and not concurrently
-      for (let i = 0; i < numConns; i++) {
+      for (let i = 0; i < numToCreate; i++) {
         try {
           // get deobfuscated value
           const config = await this._getConnAttrs();
@@ -565,8 +573,14 @@ class ThinPoolImpl extends PoolImpl {
     if (conn.nscon.connected) {
       conn._lastTimeUsed = Date.now();
       conn._newSession = false;
-      this._freeConnectionList.push(conn);
+      if ((this._freeConnectionList.length + this._usedConnectionList.size)
+        < this._poolMax) {
+        this._freeConnectionList.push(conn);
+      } else {
+        this.eventEmitter.emit('_removePoolConnection', conn);
+      }
     }
+
     this._setScheduler();
   }
 
@@ -579,6 +593,47 @@ class ThinPoolImpl extends PoolImpl {
     this._userConfig.connectionClass = crypto.randomBytes(16).toString('base64');
     this._userConfig.connectionClass = "NJS:" + this._userConfig.connectionClass;
   }
+
+  //---------------------------------------------------------------------------
+  // reconfigure()
+  //
+  // Reconfigures the pool with new parameters
+  //---------------------------------------------------------------------------
+  reconfigure(params) {
+    if (params.poolIncrement !== undefined) {
+      this._poolIncrement = params.poolIncrement;
+    }
+
+    if (params.poolTimeout !== undefined &&
+      this._poolTimeout !== params.poolTimeout) {
+      this._poolTimeout = params.poolTimeout;
+      // clear scheduled job
+      if (this._schedulerJob) {
+        clearTimeout(this._schedulerJob);
+        this._schedulerJob = null;
+      }
+    }
+
+    if (params.poolPingInterval !== undefined) {
+      this._poolPingInterval = params.poolPingInterval;
+    }
+
+    if (params.stmtCacheSize !== undefined) {
+      this._stmtCacheSize = params.stmtCacheSize;
+    }
+
+    if (params.poolMax !== undefined) {
+      this._poolMax = params.poolMax;
+    }
+
+    if (params.poolMin !== undefined) {
+      this._poolMin = params.poolMin;
+    }
+
+    if (this.bgWaiter) {
+      this.bgWaiter();
+    }
+  }
 }
 
 module.exports = ThinPoolImpl;

test/dbconfig.js

@@ -67,6 +67,9 @@ if (process.env.NODE_ORACLEDB_CONNECTIONSTRING) {
 if (process.env.NODE_ORACLEDB_EXTERNALAUTH) {
   const eauth = process.env.NODE_ORACLEDB_EXTERNALAUTH;
   if (eauth.toLowerCase() === 'true') {
+    if (oracledb.thin) {
+      throw new Error("Cannot use externalAuth with thin driver.");
+    }
     config.test.externalAuth = true;
   }
 }