diff --git a/docs/examples/java/src/main/java/com/taos/example/highvolume/DataBaseMonitor.java b/docs/examples/java/src/main/java/com/taos/example/highvolume/DataBaseMonitor.java
new file mode 100644
index 0000000000000000000000000000000000000000..04b149a4b96441ecfd1b0bdde54c9ed71349cab2
--- /dev/null
+++ b/docs/examples/java/src/main/java/com/taos/example/highvolume/DataBaseMonitor.java
@@ -0,0 +1,63 @@
+package com.taos.example.highvolume;
+
+import java.sql.*;
+
+/**
+ * Prepare target database.
+ * Count total records in database periodically so that we can estimate the writing speed.
+ */
+public class DataBaseMonitor {
+ private Connection conn;
+ private Statement stmt;
+
+ public DataBaseMonitor init() throws SQLException {
+ if (conn == null) {
+ String jdbcURL = System.getenv("TDENGINE_JDBC_URL");
+ conn = DriverManager.getConnection(jdbcURL);
+ stmt = conn.createStatement();
+ }
+ return this;
+ }
+
+ public void close() {
+ try {
+ stmt.close();
+ } catch (SQLException e) {
+ }
+ try {
+ conn.close();
+ } catch (SQLException e) {
+ }
+ }
+
+ public void prepareDatabase() throws SQLException {
+ stmt.execute("DROP DATABASE IF EXISTS test");
+ stmt.execute("CREATE DATABASE test");
+ stmt.execute("CREATE STABLE test.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (location BINARY(64), groupId INT)");
+ }
+
+ public Long count() throws SQLException {
+ if (!stmt.isClosed()) {
+ ResultSet result = stmt.executeQuery("SELECT count(*) from test.meters");
+ result.next();
+ return result.getLong(1);
+ }
+ return null;
+ }
+
+ /**
+ * show test.stables;
+ *
+ * name | created_time | columns | tags | tables |
+ * ============================================================================================
+ * meters | 2022-07-20 08:39:30.902 | 4 | 2 | 620000 |
+ */
+ public Long getTableCount() throws SQLException {
+ if (!stmt.isClosed()) {
+ ResultSet result = stmt.executeQuery("show test.stables");
+ result.next();
+ return result.getLong(5);
+ }
+ return null;
+ }
+}
\ No newline at end of file
diff --git a/docs/examples/java/src/main/java/com/taos/example/highvolume/FastWriteExample.java b/docs/examples/java/src/main/java/com/taos/example/highvolume/FastWriteExample.java
new file mode 100644
index 0000000000000000000000000000000000000000..41b59551ca69a4056c2f2b572d169bd08dc4fcfe
--- /dev/null
+++ b/docs/examples/java/src/main/java/com/taos/example/highvolume/FastWriteExample.java
@@ -0,0 +1,70 @@
+package com.taos.example.highvolume;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.sql.*;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.BlockingQueue;
+
+
+public class FastWriteExample {
+ final static Logger logger = LoggerFactory.getLogger(FastWriteExample.class);
+
+ final static int taskQueueCapacity = 1000000;
+ final static List> taskQueues = new ArrayList<>();
+ final static List readTasks = new ArrayList<>();
+ final static List writeTasks = new ArrayList<>();
+ final static DataBaseMonitor databaseMonitor = new DataBaseMonitor();
+
+ public static void stopAll() {
+ logger.info("shutting down");
+ readTasks.forEach(task -> task.stop());
+ writeTasks.forEach(task -> task.stop());
+ databaseMonitor.close();
+ }
+
+ public static void main(String[] args) throws InterruptedException, SQLException {
+ int readTaskCount = args.length > 0 ? Integer.parseInt(args[0]) : 1;
+ int writeTaskCount = args.length > 1 ? Integer.parseInt(args[1]) : 3;
+ int tableCount = args.length > 2 ? Integer.parseInt(args[2]) : 1000;
+ int maxBatchSize = args.length > 3 ? Integer.parseInt(args[3]) : 3000;
+
+ logger.info("readTaskCount={}, writeTaskCount={} tableCount={} maxBatchSize={}",
+ readTaskCount, writeTaskCount, tableCount, maxBatchSize);
+
+ databaseMonitor.init().prepareDatabase();
+
+ // Create task queues, whiting tasks and start writing threads.
+ for (int i = 0; i < writeTaskCount; ++i) {
+ BlockingQueue queue = new ArrayBlockingQueue<>(taskQueueCapacity);
+ taskQueues.add(queue);
+ WriteTask task = new WriteTask(queue, maxBatchSize);
+ Thread t = new Thread(task);
+ t.setName("WriteThread-" + i);
+ t.start();
+ }
+
+ // create reading tasks and start reading threads
+ int tableCountPerTask = tableCount / readTaskCount;
+ for (int i = 0; i < readTaskCount; ++i) {
+ ReadTask task = new ReadTask(i, taskQueues, tableCountPerTask);
+ Thread t = new Thread(task);
+ t.setName("ReadThread-" + i);
+ t.start();
+ }
+
+ Runtime.getRuntime().addShutdownHook(new Thread(FastWriteExample::stopAll));
+
+ long lastCount = 0;
+ while (true) {
+ Thread.sleep(10000);
+ long numberOfTable = databaseMonitor.getTableCount();
+ long count = databaseMonitor.count();
+ logger.info("numberOfTable={} count={} speed={}", numberOfTable, count, (count - lastCount) / 10);
+ lastCount = count;
+ }
+ }
+}
\ No newline at end of file
diff --git a/docs/examples/java/src/main/java/com/taos/example/highvolume/MockDataSource.java b/docs/examples/java/src/main/java/com/taos/example/highvolume/MockDataSource.java
new file mode 100644
index 0000000000000000000000000000000000000000..6fe83f002ebcb9d82e026e9a32886fd22bfefbe9
--- /dev/null
+++ b/docs/examples/java/src/main/java/com/taos/example/highvolume/MockDataSource.java
@@ -0,0 +1,53 @@
+package com.taos.example.highvolume;
+
+import java.util.Iterator;
+
+/**
+ * Generate test data
+ */
+class MockDataSource implements Iterator {
+ private String tbNamePrefix;
+ private int tableCount;
+ private long maxRowsPerTable = 1000000000L;
+
+ // 100 milliseconds between two neighbouring rows.
+ long startMs = System.currentTimeMillis() - maxRowsPerTable * 100;
+ private int currentRow = 0;
+ private int currentTbId = -1;
+
+ // mock values
+ String[] location = {"LosAngeles", "SanDiego", "Hollywood", "Compton", "San Francisco"};
+ float[] current = {8.8f, 10.7f, 9.9f, 8.9f, 9.4f};
+ int[] voltage = {119, 116, 111, 113, 118};
+ float[] phase = {0.32f, 0.34f, 0.33f, 0.329f, 0.141f};
+
+ public MockDataSource(String tbNamePrefix, int tableCount) {
+ this.tbNamePrefix = tbNamePrefix;
+ this.tableCount = tableCount;
+ }
+
+ @Override
+ public boolean hasNext() {
+ currentTbId += 1;
+ if (currentTbId == tableCount) {
+ currentTbId = 0;
+ currentRow += 1;
+ }
+ return currentRow < maxRowsPerTable;
+ }
+
+ @Override
+ public String next() {
+ long ts = startMs + 100 * currentRow;
+ int groupId = currentTbId % 5 == 0 ? currentTbId / 5 : currentTbId / 5 + 1;
+ StringBuilder sb = new StringBuilder(tbNamePrefix + "_" + currentTbId + ","); // tbName
+ sb.append(ts).append(','); // ts
+ sb.append(current[currentRow % 5]).append(','); // current
+ sb.append(voltage[currentRow % 5]).append(','); // voltage
+ sb.append(phase[currentRow % 5]).append(','); // phase
+ sb.append(location[currentRow % 5]).append(','); // location
+ sb.append(groupId); // groupID
+
+ return sb.toString();
+ }
+}
\ No newline at end of file
diff --git a/docs/examples/java/src/main/java/com/taos/example/highvolume/ReadTask.java b/docs/examples/java/src/main/java/com/taos/example/highvolume/ReadTask.java
new file mode 100644
index 0000000000000000000000000000000000000000..a6fcfed1d28281d46aff493ef9783972858ebe62
--- /dev/null
+++ b/docs/examples/java/src/main/java/com/taos/example/highvolume/ReadTask.java
@@ -0,0 +1,58 @@
+package com.taos.example.highvolume;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Iterator;
+import java.util.List;
+import java.util.concurrent.BlockingQueue;
+
+class ReadTask implements Runnable {
+ private final static Logger logger = LoggerFactory.getLogger(ReadTask.class);
+ private final int taskId;
+ private final List> taskQueues;
+ private final int queueCount;
+ private final int tableCount;
+ private boolean active = true;
+
+ public ReadTask(int readTaskId, List> queues, int tableCount) {
+ this.taskId = readTaskId;
+ this.taskQueues = queues;
+ this.queueCount = queues.size();
+ this.tableCount = tableCount;
+ }
+
+ /**
+ * Assign data received to different queues.
+ * Here we use the suffix number in table name.
+ * You are expected to define your own rule in practice.
+ *
+ * @param line record received
+ * @return which queue to use
+ */
+ public int getQueueId(String line) {
+ String tbName = line.substring(0, line.indexOf(',')); // For example: tb1_101
+ String suffixNumber = tbName.split("_")[1];
+ return Integer.parseInt(suffixNumber) % this.queueCount;
+ }
+
+ @Override
+ public void run() {
+ logger.info("started");
+ Iterator it = new MockDataSource("tb" + this.taskId, tableCount);
+ try {
+ while (it.hasNext() && active) {
+ String line = it.next();
+ int queueId = getQueueId(line);
+ taskQueues.get(queueId).put(line);
+ }
+ } catch (Exception e) {
+ logger.error("Read Task Error", e);
+ }
+ }
+
+ public void stop() {
+ logger.info("stop");
+ this.active = false;
+ }
+}
\ No newline at end of file
diff --git a/docs/examples/java/src/main/java/com/taos/example/highvolume/SQLWriter.java b/docs/examples/java/src/main/java/com/taos/example/highvolume/SQLWriter.java
new file mode 100644
index 0000000000000000000000000000000000000000..c2989acdbe3d0f56d7451ac86051a55955ce14de
--- /dev/null
+++ b/docs/examples/java/src/main/java/com/taos/example/highvolume/SQLWriter.java
@@ -0,0 +1,205 @@
+package com.taos.example.highvolume;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.sql.*;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * A helper class encapsulate the logic of writing using SQL.
+ *
+ * The main interfaces are two methods:
+ *
+ * - {@link SQLWriter#processLine}, which receive raw lines from WriteTask and group them by table names.
+ * - {@link SQLWriter#flush}, which assemble INSERT statement and execute it.
+ *
+ *
+ * There is a technical skill worth mentioning: we create table as needed when "table does not exist" error occur instead of creating table automatically using syntax "INSET INTO tb USING stb".
+ * This ensure that checking table existence is a one-time-only operation.
+ *
+ *
+ *
+ */
+public class SQLWriter {
+ final static Logger logger = LoggerFactory.getLogger(SQLWriter.class);
+
+ private Connection conn;
+ private Statement stmt;
+
+ /**
+ * current number of buffered records
+ */
+ private int bufferedCount = 0;
+ /**
+ * Maximum number of buffered records.
+ * Flush action will be triggered if bufferedCount reached this value,
+ */
+ private int maxBatchSize;
+
+
+ /**
+ * Maximum SQL length.
+ */
+ private int maxSQLLength;
+
+ /**
+ * Map from table name to column values. For example:
+ * "tb001" -> "(1648432611249,2.1,114,0.09) (1648432611250,2.2,135,0.2)"
+ */
+ private Map tbValues = new HashMap<>();
+
+ /**
+ * Map from table name to tag values in the same order as creating stable.
+ * Used for creating table.
+ */
+ private Map tbTags = new HashMap<>();
+
+ public SQLWriter(int maxBatchSize) {
+ this.maxBatchSize = maxBatchSize;
+ }
+
+
+ /**
+ * Get Database Connection
+ *
+ * @return Connection
+ * @throws SQLException
+ */
+ private static Connection getConnection() throws SQLException {
+ String jdbcURL = System.getenv("TDENGINE_JDBC_URL");
+ return DriverManager.getConnection(jdbcURL);
+ }
+
+ /**
+ * Create Connection and Statement
+ *
+ * @throws SQLException
+ */
+ public void init() throws SQLException {
+ conn = getConnection();
+ stmt = conn.createStatement();
+ stmt.execute("use test");
+ ResultSet rs = stmt.executeQuery("show variables");
+ while (rs.next()) {
+ String configName = rs.getString(1);
+ if ("maxSQLLength".equals(configName)) {
+ maxSQLLength = Integer.parseInt(rs.getString(2));
+ logger.info("maxSQLLength={}", maxSQLLength);
+ }
+ }
+ }
+
+ /**
+ * Convert raw data to SQL fragments, group them by table name and cache them in a HashMap.
+ * Trigger writing when number of buffered records reached maxBachSize.
+ *
+ * @param line raw data get from task queue in format: tbName,ts,current,voltage,phase,location,groupId
+ */
+ public void processLine(String line) throws SQLException {
+ bufferedCount += 1;
+ int firstComma = line.indexOf(',');
+ String tbName = line.substring(0, firstComma);
+ int lastComma = line.lastIndexOf(',');
+ int secondLastComma = line.lastIndexOf(',', lastComma - 1);
+ String value = "(" + line.substring(firstComma + 1, secondLastComma) + ") ";
+ if (tbValues.containsKey(tbName)) {
+ tbValues.put(tbName, tbValues.get(tbName) + value);
+ } else {
+ tbValues.put(tbName, value);
+ }
+ if (!tbTags.containsKey(tbName)) {
+ String location = line.substring(secondLastComma + 1, lastComma);
+ String groupId = line.substring(lastComma + 1);
+ String tagValues = "('" + location + "'," + groupId + ')';
+ tbTags.put(tbName, tagValues);
+ }
+ if (bufferedCount == maxBatchSize) {
+ flush();
+ }
+ }
+
+
+ /**
+ * Assemble INSERT statement using buffered SQL fragments in Map {@link SQLWriter#tbValues} and execute it.
+ * In case of "Table does not exit" exception, create all tables in the sql and retry the sql.
+ */
+ public void flush() throws SQLException {
+ StringBuilder sb = new StringBuilder("INSERT INTO ");
+ for (Map.Entry entry : tbValues.entrySet()) {
+ String tableName = entry.getKey();
+ String values = entry.getValue();
+ String q = tableName + " values " + values + " ";
+ if (sb.length() + q.length() > maxSQLLength) {
+ executeSQL(sb.toString());
+ logger.warn("increase maxSQLLength or decrease maxBatchSize to gain better performance");
+ sb = new StringBuilder("INSERT INTO ");
+ }
+ sb.append(q);
+ }
+ executeSQL(sb.toString());
+ tbValues.clear();
+ bufferedCount = 0;
+ }
+
+ private void executeSQL(String sql) throws SQLException {
+ try {
+ stmt.executeUpdate(sql);
+ } catch (SQLException e) {
+ // convert to error code defined in taoserror.h
+ int errorCode = e.getErrorCode() & 0xffff;
+ if (errorCode == 0x362 || errorCode == 0x218) {
+ // Table does not exist
+ createTables();
+ executeSQL(sql);
+ } else {
+ logger.error("Execute SQL: {}", sql);
+ throw e;
+ }
+ } catch (Throwable throwable) {
+ logger.error("Execute SQL: {}", sql);
+ throw throwable;
+ }
+ }
+
+ /**
+ * Create tables in batch using syntax:
+ *
+ * CREATE TABLE [IF NOT EXISTS] tb_name1 USING stb_name TAGS (tag_value1, ...) [IF NOT EXISTS] tb_name2 USING stb_name TAGS (tag_value2, ...) ...;
+ *
+ */
+ private void createTables() throws SQLException {
+ StringBuilder sb = new StringBuilder("CREATE TABLE ");
+ for (String tbName : tbValues.keySet()) {
+ String tagValues = tbTags.get(tbName);
+ sb.append("IF NOT EXISTS ").append(tbName).append(" USING meters TAGS ").append(tagValues).append(" ");
+ }
+ String sql = sb.toString();
+ try {
+ stmt.executeUpdate(sql);
+ } catch (Throwable throwable) {
+ logger.error("Execute SQL: {}", sql);
+ throw throwable;
+ }
+ }
+
+ public boolean hasBufferedValues() {
+ return bufferedCount > 0;
+ }
+
+ public int getBufferedCount() {
+ return bufferedCount;
+ }
+
+ public void close() {
+ try {
+ stmt.close();
+ } catch (SQLException e) {
+ }
+ try {
+ conn.close();
+ } catch (SQLException e) {
+ }
+ }
+}
\ No newline at end of file
diff --git a/docs/examples/java/src/main/java/com/taos/example/highvolume/StmtWriter.java b/docs/examples/java/src/main/java/com/taos/example/highvolume/StmtWriter.java
new file mode 100644
index 0000000000000000000000000000000000000000..8ade06625d708a112c85d5657aa00bcd0e605ff4
--- /dev/null
+++ b/docs/examples/java/src/main/java/com/taos/example/highvolume/StmtWriter.java
@@ -0,0 +1,4 @@
+package com.taos.example.highvolume;
+
+public class StmtWriter {
+}
diff --git a/docs/examples/java/src/main/java/com/taos/example/highvolume/WriteTask.java b/docs/examples/java/src/main/java/com/taos/example/highvolume/WriteTask.java
new file mode 100644
index 0000000000000000000000000000000000000000..de9e5463d7dc59478f991e4783aacaae527b4c4b
--- /dev/null
+++ b/docs/examples/java/src/main/java/com/taos/example/highvolume/WriteTask.java
@@ -0,0 +1,58 @@
+package com.taos.example.highvolume;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.concurrent.BlockingQueue;
+
+class WriteTask implements Runnable {
+ private final static Logger logger = LoggerFactory.getLogger(WriteTask.class);
+ private final int maxBatchSize;
+
+ // the queue from which this writing task get raw data.
+ private final BlockingQueue queue;
+
+ // A flag indicate whether to continue.
+ private boolean active = true;
+
+ public WriteTask(BlockingQueue taskQueue, int maxBatchSize) {
+ this.queue = taskQueue;
+ this.maxBatchSize = maxBatchSize;
+ }
+
+ @Override
+ public void run() {
+ logger.info("started");
+ String line = null; // data getting from the queue just now.
+ SQLWriter writer = new SQLWriter(maxBatchSize);
+ try {
+ writer.init();
+ while (active) {
+ line = queue.poll();
+ if (line != null) {
+ // parse raw data and buffer the data.
+ writer.processLine(line);
+ } else if (writer.hasBufferedValues()) {
+ // write data immediately if no more data in the queue
+ writer.flush();
+ } else {
+ // sleep a while to avoid high CPU usage if no more data in the queue and no buffered records, .
+ Thread.sleep(100);
+ }
+ }
+ if (writer.hasBufferedValues()) {
+ writer.flush();
+ }
+ } catch (Exception e) {
+ String msg = String.format("line=%s, bufferedCount=%s", line, writer.getBufferedCount());
+ logger.error(msg, e);
+ } finally {
+ writer.close();
+ }
+ }
+
+ public void stop() {
+ logger.info("stop");
+ this.active = false;
+ }
+}
\ No newline at end of file