<!DOCTYPE html><htmllang='en'><head><title>Documentation | Taos Data</title><metaname='description'content='TDengine is an open-source big data platform for IoT. Along with a 10x faster time-series database, it provides caching, stream computing, message queuing, and other functionalities. It is designed and optimized for Internet of Things, Connected Cars, and Industrial IoT. Read the documentation for TDengine here to get started right away.'><metaname='keywords'content='TDengine, Big Data, Open Source, IoT, Connected Cars, Industrial IoT, time-series database, caching, stream computing, message queuing, IT infrastructure monitoring, application performance monitoring, Internet of Things,TAOS Data, Documentation, programming, coding, syntax, frequently asked questions, questions, faq'><metaname='title'content='Documentation | Taos Data'><metaproperty='og:site_name'content='Taos Data'/><metaproperty='og:title'content='Documentation | Taos Data'/><metaproperty='og:type'content='article'/><metaproperty='og:url'content='https://www.taosdata.com/en/documentation/faq/index.php'/><metaproperty='og:description'content='TDengine is an open-source big data platform for IoT. Along with a 10x faster time-series database, it provides caching, stream computing, message queuing, and other functionalities. It is designed and optimized for Internet of Things, Connected Cars, and Industrial IoT. Read the documentation for TDengine here to get started right away.'/><linkrel='canonical'href='https://www.taosdata.com/en/documentation/faq/index.php'/><script src='../lib/jquery-3.4.1.min.js'type='application/javascript'></script><linkhref='../lib/bootstrap.min.css'rel='stylesheet'><linkhref='../styles/base.min.css'rel='stylesheet'><linkrel='stylesheet'href='../lib/docs/taosdataprettify.css'><linkrel='stylesheet'href='../lib/docs/docs.css'><script src='../lib/docs/prettify.js'></script><script src='../lib/docs/prettyprint-sql.js'></script></head><body><script>$('#documentation-href').addClass('active')</script><divclass='container-fluid'><mainclass='content-wrapper'><sectionclass='documentation'><ahref='../index.html'>Back</a><h1>FAQ</h1>
<!DOCTYPE html><htmllang='en'><head><title>Documentation | Taos Data</title><metaname='description'content='TDengine is an open-source big data platform for IoT. Along with a 10x faster time-series database, it provides caching, stream computing, message queuing, and other functionalities. It is designed and optimized for Internet of Things, Connected Cars, and Industrial IoT. Read the documentation for TDengine here to get started right away.'><metaname='keywords'content='TDengine, Big Data, Open Source, IoT, Connected Cars, Industrial IoT, time-series database, caching, stream computing, message queuing, IT infrastructure monitoring, application performance monitoring, Internet of Things,TAOS Data, Documentation, programming, coding, syntax, frequently asked questions, questions, faq'><metaname='title'content='Documentation | Taos Data'><metaproperty='og:site_name'content='Taos Data'/><metaproperty='og:title'content='Documentation | Taos Data'/><metaproperty='og:type'content='article'/><metaproperty='og:url'content='https://www.taosdata.com/en/documentation/faq/index.php'/><metaproperty='og:description'content='TDengine is an open-source big data platform for IoT. Along with a 10x faster time-series database, it provides caching, stream computing, message queuing, and other functionalities. It is designed and optimized for Internet of Things, Connected Cars, and Industrial IoT. Read the documentation for TDengine here to get started right away.'/><linkrel='canonical'href='https://www.taosdata.com/en/documentation/faq/index.php'/><script src='../lib/jquery-3.4.1.min.js'type='application/javascript'></script><linkhref='../lib/bootstrap.min.css'rel='stylesheet'><linkhref='../styles/base.min.css'rel='stylesheet'><linkrel='stylesheet'href='../lib/docs/taosdataprettify.css'><linkrel='stylesheet'href='../lib/docs/docs.css'><script src='../lib/docs/prettify.js'></script><script src='../lib/docs/prettyprint-sql.js'></script></head><body><script>$('#documentation-href').addClass('active')</script><divclass='container-fluid'><mainclass='content-wrapper'><sectionclass='documentation'><ahref='../index.html'>Back</a><h1>FAQ</h1>
<h4>1. When encoutered with the error "failed to connect to server", what can I do?</h4>
<h4>1. When encountered with the error "failed to connect to server", what can I do?</h4>
<p>The client may encounter connection errors. Please follow the steps below for troubleshooting:</p>
<p>The client may encounter connection errors. Please follow the steps below for troubleshooting:</p>
<ol>
<ol>
<li>On the server side, execute <code>systemctl status taosd</code> to check the status of <em>taosd</em> service. If <em>taosd</em> is not running, start it and retry connecting.</li>
<li>On the server side, execute <code>systemctl status taosd</code> to check the status of <em>taosd</em> service. If <em>taosd</em> is not running, start it and retry connecting.</li>
if $system_content != @{"status":"succ","head":["name","created_time","ntables","vgroups","replica","quorum","days","keep0,keep1,keep(D)","cache(MB)","blocks","minrows","maxrows","wallevel","fsync","comp","cachelast","precision","update","status"],"data":[],"rows":0}@ then
if $system_content != @{"status":"succ","head":["name","created_time","ntables","vgroups","replica","quorum","days","keep0,keep1,keep(D)","cache(MB)","blocks","minrows","maxrows","wallevel","fsync","comp","cachelast","precision","update","status"],"column_meta":[["name",8,32],["created_time",9,8],["ntables",4,4],["vgroups",4,4],["replica",3,2],["quorum",3,2],["days",3,2],["keep0,keep1,keep(D)",8,24],["cache(MB)",4,4],["blocks",4,4],["minrows",4,4],["maxrows",4,4],["wallevel",2,1],["fsync",4,4],["comp",2,1],["cachelast",2,1],["precision",8,3],["update",2,1],["status",8,10]],"data":[],"rows":0}@ then
if $system_content != @{"status":"succ","head":["ts","speed"],"data":[["2017-12-25 21:28:41.022",1]],"rows":1}@ then
if $system_content != @{"status":"succ","head":["ts","speed"],"column_meta":[["ts",9,8],["speed",4,4]],"data":[["2017-12-25 21:28:41.022",1]],"rows":1}@ then
if $system_content != @{"status":"succ","head":["ts","speed"],"data":[["2017-12-25 21:28:41.022",1]],"rows":1}@ then
if $system_content != @{"status":"succ","head":["ts","speed"],"column_meta":[["ts",9,8],["speed",4,4]],"data":[["2017-12-25 21:28:41.022",1]],"rows":1}@ then
system_content curl -u root:taosdata -d 'select * from db.sys_cpu_d_bbb_lga_1_web01' 127.0.0.1:7111/rest/sql/
system_content curl -u root:taosdata -d 'select * from db.sys_cpu_d_bbb_lga_1_web01' 127.0.0.1:7111/rest/sql/
print $system_content
print $system_content
if $system_content != @{"status":"succ","head":["ts","value"],"data":[["2012-09-05 20:00:00.000",18.000000000]],"rows":1}@ then
if $system_content != @{"status":"succ","head":["ts","value"],"column_meta":[["ts",9,8],["value",7,8]],"data":[["2012-09-05 20:00:00.000",18.000000000]],"rows":1}@ then
if $system_content != @{"status":"succ","head":["ts","value"],"data":[["2012-09-05 20:00:00.000",18.000000000],["2012-09-05 20:00:05.000",18.000000000]],"rows":2}@ then
if $system_content != @{"status":"succ","head":["ts","value"],"column_meta":[["ts",9,8],["value",7,8]],"data":[["2012-09-05 20:00:00.000",18.000000000],["2012-09-05 20:00:05.000",18.000000000]],"rows":2}@ then
if $system_content != @{"status":"succ","head":["ts","value"],"data":[["2012-09-05 20:00:00.000",8.000000000],["2012-09-05 20:00:05.000",9.000000000]],"rows":2}@ then
if $system_content != @{"status":"succ","head":["ts","value"],"column_meta":[["ts",9,8],["value",7,8]],"data":[["2012-09-05 20:00:00.000",8.000000000],["2012-09-05 20:00:05.000",9.000000000]],"rows":2}@ then
