Merge pull request #14922 from taosdata/docs/TD-17370

docs： python and java examples

docs/examples/java/src/main/java/com/taos/example/highvolume/DataBaseMonitor.java

+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;
+    }
+}
\ No newline at end of file

docs/examples/java/src/main/java/com/taos/example/highvolume/FastWriteExample.java

@@ -9,51 +9,7 @@ import java.util.List;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.BlockingQueue;
 
-/**
- * Prepare target database.
- * Count total records in database periodically so that we can estimate the writing speed.
- */
-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;
-    }
-}
-
-// ANCHOR: main
 public class FastWriteExample {
     final static Logger logger = LoggerFactory.getLogger(FastWriteExample.class);
 
@@ -110,5 +66,4 @@ public class FastWriteExample {
             lastCount = count;
         }
     }
-}
-// ANCHOR_END: main
+}
\ No newline at end of file
\ No newline at end of file

docs/examples/java/src/main/java/com/taos/example/highvolume/MockDataSource.java

+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

docs/examples/java/src/main/java/com/taos/example/highvolume/ReadTask.java

@@ -7,57 +7,6 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.concurrent.BlockingQueue;
 
-/**
- * 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();
-    }
-}
-
-// ANCHOR: ReadTask
 class ReadTask implements Runnable {
     private final static Logger logger = LoggerFactory.getLogger(ReadTask.class);
     private final int taskId;
@@ -106,6 +55,4 @@ class ReadTask implements Runnable {
         logger.info("stop");
         this.active = false;
     }
-}
-
+}
\ No newline at end of file
-// ANCHOR_END: ReadTask
\ No newline at end of file

docs/examples/java/src/main/java/com/taos/example/highvolume/SQLWriter.java

@@ -7,8 +7,6 @@ import java.sql.*;
 import java.util.HashMap;
 import java.util.Map;
 
-// ANCHOR: SQLWriter
-
 /**
  * A helper class encapsulate the logic of writing using SQL.
  * <p>
@@ -154,10 +152,14 @@ public class SQLWriter {
             if (errorCode == 0x362 || errorCode == 0x218) {
                 // Table does not exist
                 createTables();
-                stmt.executeUpdate(sql);
+                executeSQL(sql);
             } else {
+                logger.error("Execute SQL: {}", sql);
                 throw e;
             }
+        } catch (Throwable throwable) {
+            logger.error("Execute SQL: {}", sql);
+            throw throwable;
         }
     }
 
@@ -174,7 +176,12 @@ public class SQLWriter {
             sb.append("IF NOT EXISTS ").append(tbName).append(" USING meters TAGS ").append(tagValues).append(" ");
         }
         String sql = sb.toString();
-        stmt.executeUpdate(sql);
+        try {
+            stmt.executeUpdate(sql);
+        } catch (Throwable throwable) {
+            logger.error("Execute SQL: {}", sql);
+            throw throwable;
+        }
     }
 
     public boolean hasBufferedValues() {
@@ -195,5 +202,4 @@ public class SQLWriter {
         } catch (SQLException e) {
         }
     }
-}
-// ANCHOR_END: SQLWriter
+}
\ No newline at end of file

docs/examples/java/src/main/java/com/taos/example/highvolume/StmtWriter.java

+package com.taos.example.highvolume;
+
+public class StmtWriter {
+}

docs/examples/java/src/main/java/com/taos/example/highvolume/WriteTask.java

@@ -5,7 +5,6 @@ import org.slf4j.LoggerFactory;
 
 import java.util.concurrent.BlockingQueue;
 
-// ANCHOR: WriteTask
 class WriteTask implements Runnable {
     private final static Logger logger = LoggerFactory.getLogger(WriteTask.class);
     private final int maxBatchSize;
@@ -56,5 +55,4 @@ class WriteTask implements Runnable {
         logger.info("stop");
         this.active = false;
     }
-}
-// ANCHOR_END: WriteTask
+}
\ No newline at end of file
\ No newline at end of file

docs/examples/java/src/main/resources/highvolume2.drawio

+<mxfile host="65bd71144e">
+    <diagram id="_BjMg4p5x31hL4Gv-87s" name="第 1 页">
+        <mxGraphModel dx="1259" dy="615" grid="0" gridSize="10" guides="1" tooltips="1" connect="1" arrows="1" fold="1" page="1" pageScale="1" pageWidth="900" pageHeight="900" background="none" math="0" shadow="0">
+            <root>
+                <mxCell id="0"/>
+                <mxCell id="1" parent="0"/>
+                <mxCell id="13" style="edgeStyle=none;html=1;exitX=1;exitY=0.5;exitDx=0;exitDy=0;fontSize=17;" parent="1" source="7" edge="1">
+                    <mxGeometry relative="1" as="geometry">
+                        <mxPoint x="260" y="150" as="targetPoint"/>
+                    </mxGeometry>
+                </mxCell>
+                <mxCell id="7" value="&lt;font style=&quot;font-size: 14px&quot;&gt;Read Task 1&lt;/font&gt;" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#dae8fc;strokeColor=#6c8ebf;fontStyle=1" parent="1" vertex="1">
+                    <mxGeometry x="60" y="160" width="100" height="37" as="geometry"/>
+                </mxCell>
+                <mxCell id="18" style="edgeStyle=none;html=1;exitX=1;exitY=0.5;exitDx=0;exitDy=0;fontSize=17;" parent="1" source="8" edge="1">
+                    <mxGeometry relative="1" as="geometry">
+                        <mxPoint x="264" y="292" as="targetPoint"/>
+                    </mxGeometry>
+                </mxCell>
+                <mxCell id="8" value="&lt;font style=&quot;font-size: 14px&quot;&gt;&lt;font style=&quot;font-size: 14px&quot;&gt;Read Tas&lt;/font&gt;&lt;font style=&quot;font-size: 14px&quot;&gt;k 2&lt;/font&gt;&lt;/font&gt;" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#dae8fc;strokeColor=#6c8ebf;fontStyle=1" parent="1" vertex="1">
+                    <mxGeometry x="60" y="240" width="100" height="36" as="geometry"/>
+                </mxCell>
+                <mxCell id="23" value="" style="edgeStyle=none;html=1;fontSize=14;" parent="1" source="9" target="20" edge="1">
+                    <mxGeometry relative="1" as="geometry"/>
+                </mxCell>
+                <mxCell id="9" value="Queue 1" style="rounded=0;whiteSpace=wrap;html=1;fontSize=17;fillColor=#f8cecc;strokeColor=#b85450;" parent="1" vertex="1">
+                    <mxGeometry x="265" y="130" width="245" height="30" as="geometry"/>
+                </mxCell>
+                <mxCell id="24" value="" style="edgeStyle=none;html=1;fontSize=14;" parent="1" source="10" target="21" edge="1">
+                    <mxGeometry relative="1" as="geometry"/>
+                </mxCell>
+                <mxCell id="10" value="Queue 2" style="rounded=0;whiteSpace=wrap;html=1;fontSize=17;fillColor=#f8cecc;strokeColor=#b85450;" parent="1" vertex="1">
+                    <mxGeometry x="265" y="175" width="245" height="30" as="geometry"/>
+                </mxCell>
+                <mxCell id="25" value="" style="edgeStyle=none;html=1;fontSize=14;entryX=0;entryY=0.5;entryDx=0;entryDy=0;" parent="1" source="11" target="28" edge="1">
+                    <mxGeometry relative="1" as="geometry">
+                        <mxPoint x="600" y="284.1428571428571" as="targetPoint"/>
+                    </mxGeometry>
+                </mxCell>
+                <mxCell id="11" value="Queue 3" style="rounded=0;whiteSpace=wrap;html=1;fontSize=17;fillColor=#f8cecc;strokeColor=#b85450;" parent="1" vertex="1">
+                    <mxGeometry x="265" y="223" width="245" height="30" as="geometry"/>
+                </mxCell>
+                <mxCell id="14" style="edgeStyle=none;html=1;exitX=1;exitY=0.5;exitDx=0;exitDy=0;fontSize=17;entryX=0;entryY=0.5;entryDx=0;entryDy=0;" parent="1" source="7" target="11" edge="1">
+                    <mxGeometry relative="1" as="geometry">
+                        <mxPoint x="270" y="160" as="targetPoint"/>
+                        <mxPoint x="180" y="195" as="sourcePoint"/>
+                    </mxGeometry>
+                </mxCell>
+                <mxCell id="17" style="edgeStyle=none;html=1;exitX=1;exitY=0.5;exitDx=0;exitDy=0;entryX=0;entryY=0.75;entryDx=0;entryDy=0;fontSize=17;" parent="1" source="8" target="10" edge="1">
+                    <mxGeometry relative="1" as="geometry">
+                        <mxPoint x="180" y="285" as="sourcePoint"/>
+                        <mxPoint x="275" y="162.5" as="targetPoint"/>
+                    </mxGeometry>
+                </mxCell>
+                <mxCell id="20" value="&lt;font style=&quot;font-size: 14px&quot;&gt;&lt;font style=&quot;font-size: 14px&quot;&gt;Write Tas&lt;/font&gt;&lt;font style=&quot;font-size: 14px&quot;&gt;k 1&lt;/font&gt;&lt;/font&gt;" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#dae8fc;strokeColor=#6c8ebf;fontStyle=1" parent="1" vertex="1">
+                    <mxGeometry x="588" y="129" width="100" height="31" as="geometry"/>
+                </mxCell>
+                <mxCell id="21" value="&lt;font style=&quot;font-size: 14px&quot;&gt;&lt;font style=&quot;font-size: 14px&quot;&gt;Write Tas&lt;/font&gt;&lt;font style=&quot;font-size: 14px&quot;&gt;k 2&lt;/font&gt;&lt;/font&gt;" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#dae8fc;strokeColor=#6c8ebf;fontStyle=1" parent="1" vertex="1">
+                    <mxGeometry x="588" y="175" width="100" height="33" as="geometry"/>
+                </mxCell>
+                <mxCell id="30" style="edgeStyle=none;html=1;exitX=1;exitY=0.5;exitDx=0;exitDy=0;entryX=0;entryY=0.5;entryDx=0;entryDy=0;" parent="1" source="26" target="29" edge="1">
+                    <mxGeometry relative="1" as="geometry"/>
+                </mxCell>
+                <mxCell id="26" value="Queue 4" style="rounded=0;whiteSpace=wrap;html=1;fontSize=17;fillColor=#f8cecc;strokeColor=#b85450;" parent="1" vertex="1">
+                    <mxGeometry x="265" y="271" width="245" height="29" as="geometry"/>
+                </mxCell>
+                <mxCell id="28" value="&lt;font style=&quot;font-size: 14px&quot;&gt;&lt;font style=&quot;font-size: 14px&quot;&gt;Write Tas&lt;/font&gt;&lt;font style=&quot;font-size: 14px&quot;&gt;k 3&lt;/font&gt;&lt;/font&gt;" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#dae8fc;strokeColor=#6c8ebf;fontStyle=1" parent="1" vertex="1">
+                    <mxGeometry x="588" y="221.5" width="100" height="33" as="geometry"/>
+                </mxCell>
+                <mxCell id="29" value="&lt;font style=&quot;font-size: 14px&quot;&gt;&lt;font style=&quot;font-size: 14px&quot;&gt;Write Tas&lt;/font&gt;&lt;font style=&quot;font-size: 14px&quot;&gt;k 4&lt;/font&gt;&lt;/font&gt;" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#dae8fc;strokeColor=#6c8ebf;fontStyle=1" parent="1" vertex="1">
+                    <mxGeometry x="588" y="271" width="100" height="33" as="geometry"/>
+                </mxCell>
+            </root>
+        </mxGraphModel>
+    </diagram>
+</mxfile>
\ No newline at end of file

docs/examples/python/highvolume_faster_queue.py → docs/examples/python/fast_write_example.py

@@ -4,11 +4,13 @@
 #
 
 import logging
+import math
 import sys
 import time
 import os
 from multiprocessing import Process
 from faster_fifo import Queue
+from mockdatasource import MockDataSource
 from queue import Empty
 from typing import List
 
@@ -40,57 +42,18 @@ def get_connection():
     return taos.connect(host=host, port=int(port), user=user, password=password)
 
 
-# ANCHOR: MockDataSource
-class MockDataSource:
-    location = ["LosAngeles", "SanDiego", "Hollywood", "Compton", "San Francisco"]
-    current = [8.8, 10.7, 9.9, 8.9, 9.4]
-    voltage = [119, 116, 111, 113, 118]
-    phase = [0.32, 0.34, 0.33, 0.329, 0.141]
-    max_rows_per_table = 10 ** 9
-
-    def __init__(self, tb_name_prefix, table_count):
-        self.table_name_prefix = tb_name_prefix
-        self.table_count = table_count
-        self.start_ms = round(time.time() * 1000) - self.max_rows_per_table * 100
-
-    def __iter__(self):
-        self.row = 0
-        self.table_id = -1
-        return self
-
-    def __next__(self):
-        """
-        next 100 rows of current table
-        """
-        self.table_id += 1
-        if self.table_id == self.table_count:
-            self.table_id = 0
-        if self.row >= self.max_rows_per_table:
-            raise StopIteration
-        rows = []
-
-        while len(rows) < 100:
-            self.row += 1
-            ts = self.start_ms + 100 * self.row
-            group_id = self.table_id % 5 if self.table_id % 5 == 0 else self.table_id % 5 + 1
-            tb_name = self.table_name_prefix + '_' + str(self.table_id)
-            ri = self.row % 5
-            rows.append(f"{tb_name},{ts},{self.current[ri]},{self.voltage[ri]},{self.phase[ri]},{self.location[ri]},{group_id}")
-        return self.table_id, rows
-
-
-# ANCHOR_END: MockDataSource
-
 # ANCHOR: read
+
 def run_read_task(task_id: int, task_queues: List[Queue]):
     table_count_per_task = TABLE_COUNT // READ_TASK_COUNT
     data_source = MockDataSource(f"tb{task_id}", table_count_per_task)
     try:
-        for table_id, rows in data_source:
-            # hash data to different queue
-            i = table_id % len(task_queues)
-            # block putting forever when the queue is full
-            task_queues[i].put_many(rows, block=True, timeout=-1)
+        for batch in data_source:
+            for table_id, rows in batch:
+                # hash data to different queue
+                i = table_id % len(task_queues)
+                # block putting forever when the queue is full
+                task_queues[i].put_many(rows, block=True, timeout=-1)
     except KeyboardInterrupt:
         pass
 
@@ -141,7 +104,6 @@ def set_global_config():
 
 # ANCHOR: monitor
 def run_monitor_process():
-    import taos
     log = logging.getLogger("DataBaseMonitor")
     conn = get_connection()
     conn.execute("DROP DATABASE IF EXISTS test")
@@ -178,15 +140,18 @@ def main():
     for i in range(WRITE_TASK_COUNT):
         queue = Queue(max_size_bytes=QUEUE_SIZE)
         task_queues.append(queue)
+
     # create write processes
     for i in range(WRITE_TASK_COUNT):
         p = Process(target=run_write_task, args=(i, task_queues[i]))
         p.start()
         logging.debug(f"WriteTask-{i} started with pid {p.pid}")
         write_processes.append(p)
+
     # create read processes
     for i in range(READ_TASK_COUNT):
-        p = Process(target=run_read_task, args=(i, task_queues))
+        queues = assign_queues(i, task_queues)
+        p = Process(target=run_read_task, args=(i, queues))
         p.start()
         logging.debug(f"ReadTask-{i} started with pid {p.pid}")
         read_processes.append(p)
@@ -200,6 +165,16 @@ def main():
         [q.close() for q in task_queues]
 
 
+def assign_queues(read_task_id, task_queues):
+    """
+    Compute target queues for a specific read task.
+    """
+    ratio = WRITE_TASK_COUNT / READ_TASK_COUNT
+    from_index = math.floor(read_task_id * ratio)
+    end_index = math.ceil((read_task_id + 1) * ratio)
+    return task_queues[from_index:end_index]
+
+
 if __name__ == '__main__':
     main()
 # ANCHOR_END: main

docs/examples/python/mockdatasource.py

+import time
+
+
+class MockDataSource:
+    samples = [
+        "8.8,119,0.32,LosAngeles,0",
+        "10.7,116,0.34,SanDiego,1",
+        "9.9,111,0.33,Hollywood,2",
+        "8.9,113,0.329,Compton,3",
+        "9.4,118,0.141,San Francisco,4"
+    ]
+
+    def __init__(self, tb_name_prefix, table_count):
+        self.table_name_prefix = tb_name_prefix + "_"
+        self.table_count = table_count
+        self.max_rows = 10000000
+        self.current_ts = round(time.time() * 1000) - self.max_rows * 100
+        # [(tableId, tableName, values),]
+        self.data = self._init_data()
+
+    def _init_data(self):
+        lines = self.samples * (self.table_count // 5 + 1)
+        data = []
+        for i in range(self.table_count):
+            table_name = self.table_name_prefix + str(i)
+            data.append((i, table_name, lines[i]))  # tableId, row
+        return data
+
+    def __iter__(self):
+        self.row = 0
+        return self
+
+    def __next__(self):
+        """
+        next 1000 rows for each table.
+        return: {tableId:[row,...]}
+        """
+        # generate 1000 timestamps
+        ts = []
+        for _ in range(1000):
+            self.current_ts += 100
+            ts.append(str(self.current_ts))
+        # add timestamp to each row
+        # [(tableId, ["tableName,ts,current,voltage,phase,location,groupId"])]
+        result = []
+        for table_id, table_name, values in self.data:
+            rows = [table_name + ',' + t + ',' + values for t in ts]
+            result.append((table_id, rows))
+        return result

docs/examples/python/sql_writer.py

@@ -18,6 +18,7 @@ class SQLWriter:
             name = r[0]
             if name == "maxSQLLength":
                 return int(r[1])
+        return 1024 * 1024
 
     def process_lines(self, lines: str):
         """
@@ -71,11 +72,19 @@ class SQLWriter:
             if error_code == 0x362 or error_code == 0x218:
                 self.create_tables()
             else:
+                self.log.error("Execute SQL: %s", sql)
                 raise e
+        except BaseException as baseException:
+            self.log.error("Execute SQL: %s", sql)
+            raise baseException
 
     def create_tables(self):
         sql = "CREATE TABLE "
         for tb in self._tb_values.keys():
             tag_values = self._tb_tags[tb]
             sql += "IF NOT EXISTS " + tb + " USING meters TAGS " + tag_values + " "
-        self._conn.execute(sql)
+        try:
+            self._conn.execute(sql)
+        except BaseException as e:
+            self.log.error("Execute SQL: %s", sql)
+            raise e

docs/examples/python/stmt_writer.py

+class StmtWriter:
+    pass