Display query and analysis results on multiple pages

The query and analysis features of Log Service allow you to query logs based on keywords and analyze the query result by running the corresponding SQL statements. The GetLogstoreLogs operation is provided by Log Service to query logs. With this operation, you can query raw logs by keyword, compute data by running SQL statements, and obtain the analysis result. The query feature and the analysis feature implemented in query and analysis statements use different paging methods.

• Query statements: Search for records in raw logs by keyword. You can use the offset and lines parameters of the operation to obtain all required records and display them on multiple pages.
• Analysis statements: Analyze the query result by running the corresponding SQL statements and obtain the analysis result. You can get the paged result by running the SQL LIMIT statement.

Use the offset and lines parameters of the GetLogStoreLogs operation to get the paged query result.

• offset: the line from which the logs are to be read.
• lines: the number of lines to be read for the current request. The maximum value of this parameter is 100. If you set a value greater than 100, only 100 lines are returned.

• Pseudocode:

      offset = 0// Indicates that logs are read from the zeroth line.
      lines = 100// Indicates that 100 lines are read at a time.
      query = "status:200"// Indicates that the logs where the value of the status field contains 200 are queried. while True:
      response = get_logstore_logs(query, offset, lines) // The response to the read request.
      process (response)                                 // Use the custom logic to process the query result.
      If response.get_count() == 0 && response.is_complete()   
           Stop reading logs and exit the current loop.
      else
          offset += 100                                 // The value of the offset parameter increases by 100. The next 100 lines are to be read.

• Python code:
  For more information about the sample code, see Log Service Python SDK.

      endpoint = ''# The endpoint that matches the region of the project created in the preceding step.
      accessKeyId = ''# Your Alibaba Cloud AccessKey ID.
      accessKey = ''# Your Alibaba Cloud AccessKey secret.
      project = ''# The name of the project created in the preceding step.
      logstore = ''# The name of the Logstore created in the preceding step.
      client = LogClient(endpoint, accessKeyId, accessKey)
      topic = ""
      query = "index"
      From = int(time.time()) - 600
      To = int(time.time())
      log_line = 100
      offset = 0
      while True:
          res4 = Nonefor retry_time in range(0, 3):
              req4 = GetLogsRequest(project, logstore, From, To, topic, query, log_line, offset, False)
              res4 = client.get_logs(req4)
              if res4 isnotNoneand res4.is_completed():
                  break
              time.sleep(1)
          offset += 100if res4.is_completed() && res4.get_count() == 0:
                break;
          if res4 isnotNone:
              res4.log_print()  # Display the execution result.

• Java code:

  For more information about the sample code, see Log Service Java SDK.

          int log_offset = 0;
          int log_line = 100;// Indicates that 100 lines are read at a time. The maximum value of this parameter is 100. If you need to read more than 100 lines at a time, use the offset parameter. Note that the offset and lines parameters are available to keyword-based queries instead of SQL-based queries. To read more than 100 lines at a time during a SQL-based query, use the LIMIT statement.
          while (true) {
              GetLogsResponse res4 = null;
              // For each log offset, 100 lines are read at a time. If a read operation fails, a maximum of 3 retries are allowed.
              for (int retry_time = 0; retry_time < 3; retry_time++) {
                  GetLogsRequest req4 = new GetLogsRequest(project, logstore, from, to, topic, query, log_offset,
                          log_line, false);
                  res4 = client.GetLogs(req4);
  
                  if (res4 ! = null && res4.IsCompleted()) {
                      break;
                  }
                  Thread.sleep(200);
              }
              System.out.println("Read log count:" + String.valueOf(res4.GetCount()));
              log_offset += log_line;
              if (res4.IsCompleted() && res4.GetCount() == 0) {
                          break;
              }
  
          }
  						

To resolve these issues in displaying the SQL-based analysis result by page, Log Service provides the standard SQL LIMIT statement that uses the following syntax:

limit Offset, Line

• Offset: the line from which the result is to be read.
• Line: the number of lines to be read. The value of Line does not have an upper limit. However, reading too many lines at a time may result in a high network latency and an adverse impact on the processing speed of the client.

* | selectcount(1) , url  group by url  limit 0, 500
* | selectcount(1) , url  group by url  limit 500, 500
* | selectcount(1) , url  group by url  limit 1000, 500
* | selectcount(1) , url  group by url  limit 1500, 500

• Pseudocode:

      offset = 0// Indicates that logs are read from the zeroth line.
      lines = 500// Indicates that 500 lines are read at a time.
      query = "* | select count(1) , url  group by url  limit "whileTrue:
      real_query = query + offset + "," +  lines
      response = get_logstore_logs(real_query) // The response to the read request.
       process (response)                       // Use the custom logic to process the analysis result.
      If response.get_count() == 0   
           Stop reading logs and exit the current loop.
      else
          offset += 500                        // The value of the offset parameter increases by 500. The next 500 lines are to be read.

• Python code:

      endpoint = ''# The endpoint that matches the region of the project created in the preceding step.
      accessKeyId = ''# Your Alibaba Cloud AccessKey ID.
      accessKey = ''# Your Alibaba Cloud AccessKey secret.
      project = ''# The name of the project created in the preceding step.
      logstore = ''# The name of the Logstore created in the preceding step.
      client = LogClient(endpoint, accessKeyId, accessKey)
      topic = ""
      origin_query = "* | select count(1) , url  group by url  limit "
      From = int(time.time()) - 600
      To = int(time.time())
      log_line = 100
      offset = 0
      while True:
          res4 = None
          query = origin_query + str(offset) + " , " + str(log_line)
          for retry_time in range(0, 3):
              req4 = GetLogsRequest(project, logstore, From, To, topic, query)
              res4 = client.get_logs(req4)
              if res4 isnotNoneand res4.is_completed():
                  break
              time.sleep(1)
          offset += 100if res4.is_completed() && res4.get_count() == 0:
                break;
          if res4 isnotNone:
              res4.log_print()  # Display the execution result.

• Java code:

          int log_offset = 0;
          int log_line = 500;
          String origin_query = "* | select count(1) , url  group by url  limit "while (true) {
              GetLogsResponse res4 = null;
              // For each log offset, 500 lines are read at a time. If a read operation fails, a maximum of 3 retries are allowed.
              query = origin_query + log_offset + "," + log_line;
              for (int retry_time = 0; retry_time < 3; retry_time++) {
                  GetLogsRequest req4 = new GetLogsRequest(project, logstore, from, to, topic, query);
                  res4 = client.GetLogs(req4);
  
                  if (res4 ! = null && res4.IsCompleted()) {
                      break;
                  }
                  Thread.sleep(200);
              }
              System.out.println("Read log count:" + String.valueOf(res4.GetCount()));
              log_offset += log_line;
              if (res4.GetCount() == 0) {
                          break;
              }
  
          }