How to paginate query and analysis results - Simple Log Service

If a query statement returns a large number of query and analysis results, the results are displayed at a lower speed. Simple Log Service provides the paged query feature to limit the number of logs that can be returned for each query. This topic describes how to paginate query and analysis results.

How pagination works

Simple Log Service provides the query and analysis feature that allows you to execute a query statement to query logs by using keywords and analyze the query results by using SQL syntax. You can also call the GetLogs operation to query the raw data of logs by using keywords and analyze the query results by using SQL syntax. A query statement can contain a search statement and an analytic statement. The pagination methods vary between the search statement and analytic statement. For more information, see GetLogs. For more information about how to obtain the total number of log lines, see GetHistograms.

Search statement: queries the raw data of logs by using keywords. You can configure the offset and line parameters in the GetLogs operation to perform a paged query. For more information, see Log search overview.
Analytic statement: analyzes query results by using SQL syntax. You can use a LIMIT clause to perform a paged query. For more information, see Log analysis overview and LIMIT clause.

Paginate query results

The following list describes the offset and line parameters in the GetLogs operation:

offset: the line from which query results are read.
line: the number of lines that are returned for the current API request. A maximum of 100 lines can be returned. If you set this parameter to a value greater than 100, only 100 lines are returned.

When a paged query is performed, the value of the offset parameter increases until all logs are read. When the value reaches a specific number, 0 is returned, and the progress is complete. In this case, all the required data is read.

Sample code for pagination

offset = 0                           # Read logs from line 0. 
line = 100                          # Read 100 lines at a time. 
query = "status:200"                 # Query all logs in which the value of the status field is 200. 
while True:
     response = get_logstore_logs(query, offset, line) # Call the operation to read logs. 
     process (response)                                 # Call custom logic to process the returned result. 
     if response.get_count() == 0 && response.is_complete()   
         The read process is complete, and the current loop ends.
     else
        offset += 100                          # The value of the offset parameter increases to 100. The next 100 lines are read.

Sample code in Python

For more information, see Overview of Simple Log Service SDK for Python.

# The Simple Log Service endpoint. 
endpoint = '' 
# Configure environment variables. In this example, the AccessKey ID and AccessKey secret are obtained from environment variables. 
accessKeyId = os.environ.get('ALIBABA_CLOUD_ACCESS_KEY_ID', '')
accessKey = os.environ.get('ALIBABA_CLOUD_ACCESS_KEY_SECRET', '')
# The name of the project. 
project = ''     
# The name of the Logstore. 
logstore = ''  
client = LogClient(endpoint, accessKeyId, accessKey)
topic = ""
From = int(time.time()) - 600
To = int(time.time())
log_line = 100
offset = 0
while True:
    res4 = None
    for retry_time in range(0, 3): 
        req4 = GetLogsRequest(project, logstore, From, To, topic=topic, line=log_line, offset=offset)
        res4 = client.get_logs(req4)
        if res4 is not None and res4.is_completed():
            break
        time.sleep(1)
     offset += 100 
     if res4.is_completed() and res4.get_count() == 0:
         break;
     if res4 is not None:
         # Display the execution result. 
        res4.log_print()

Sample code in Java

For more information, see Overview of Simple Log Service SDK for Java.

int log_offset = 0;
int log_line = 100;   // The number of lines that are read at a time. A maximum of 100 lines can be returned. If you want to read more than 100 lines, use the offset parameter. The offset and line parameters take effect only for a search statement that uses keywords. If you use an analytic statement, these parameters are invalid. If you want an analytic statement to return more than 100 lines, use the LIMIT clause. 
while (true) {
    GetLogsResponse res4 = null;
    // For each offset, 100 lines are read at a time. If the read operation fails, a maximum of three 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;
            }
 }

Paginate analysis results

You can use a LIMIT clause to paginate analysis results. Example:

limit Offset, Line

The following list describes the offset and line parameters:

offset: the line from which analysis results are read.
line: the number of lines that are returned for the current API request. A maximum of 1,000,000 lines can be returned. If a large number of lines are read at a time, the network delay increases, and the client-side processing speed decreases.

For example, if you want to use the * | select count(1) , url group by url statement to return 2,000 lines, you can execute the following statements to perform 4 paged queries and query 500 lines each time:

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

Sample code for pagination

offset = 0     // Read logs from line 0. 
line = 500    // Read 500 lines at a time. 
query = "* | select count(1) , url  group by url  limit "
while True:
real_query = query + offset + "," +  line
response = get_logstore_logs(real_query) // Call the operation to read logs. 
process (response)                       // Call custom logic to process the returned result. 
if response.get_count() == 0   
    The read process is complete, and the current loop ends.
else
    offset += 500                        // The value of the offset parameter increases to 500. The next 500 lines are read.

Sample code in Python

For more information, see Overview of Simple Log Service SDK for Python.

# The Simple Log Service endpoint.
endpoint = '' 
# Configure environment variables. In this example, the AccessKey ID and AccessKey secret are obtained from environment variables. 
accessKeyId = os.environ.get('ALIBABA_CLOUD_ACCESS_KEY_ID', '')
accessKey = os.environ.get('ALIBABA_CLOUD_ACCESS_KEY_SECRET', '')
# The name of the project. 
project = ''     
# The name of the Logstore. 
logstore = ''  
client = LogClient(endpoint, accessKeyId, accessKey)
topic = ""
origin_query = "* | select *  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=topic, query=query)
        res4 = client.get_logs(req4)
        if res4 is not None and res4.is_completed():
            break
        time.sleep(1)
    offset += 100 
    if res4.is_completed() and res4.get_count() == 0:
        break;
    if res4 is not None:
    # Display the execution result. 
        res4.log_print()

Sample code in Java

For more information, see Overview of Simple Log Service SDK for Java.

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 offset, 500 lines are read at a time. If the read operation fails, a maximum of three 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;
            }
}