Hi, That link contains the settings provided by Cloudera Manager to monitor impala services, I do not think that's what you are looking for. They are specific to Cloudera Manager, not part of Impala. Cloudera Manager internally queries this page provided by Impala daemon host: http://<impala-daemon-url>:25000/inflight_query_ids to determine if the impala is responding to requests. This page will return a list of query IDs that is inflight. How long it takes to get a response and how many queries are running at a time, could give you some indication of the health of the impala daemon. Hope this helps. ... View more

ALTER TABLE test CHANGE {columname} {columnname} {datatype} comment 'test comment'; See below test case:   [impala-host:21000] > show create table test; Query: show create table test +---------------------------------------------------------------------------------------------------------------------+ | result | +---------------------------------------------------------------------------------------------------------------------+ | CREATE TABLE default.test ( | | a INT, | | b INT | | ) | | WITH SERDEPROPERTIES ('serialization.format'='1') | | STORED AS TEXTFILE | | LOCATION 'hdfs://namenode-host:8020/user/hive/warehouse/test' | | TBLPROPERTIES ('numFiles'='3', 'COLUMN_STATS_ACCURATE'='true', 'numRows'='9', 'totalSize'='40', 'rawDataSize'='31') | +---------------------------------------------------------------------------------------------------------------------+ Fetched 1 row(s) in 7.42s [impala-host:21000] > alter table test change a a int comment 'test comment'; Query: alter table test change a a int comment 'test comment' Fetched 0 row(s) in 0.66s [impala-host:21000] > show create table test; Query: show create table test +---------------------------------------------------------------------------------------------------------------------+ | result | +---------------------------------------------------------------------------------------------------------------------+ | CREATE TABLE default.test ( | | a INT COMMENT 'test comment', | | b INT | | ) | | WITH SERDEPROPERTIES ('serialization.format'='1') | | STORED AS TEXTFILE | | LOCATION 'hdfs://namenode-host:8020/user/hive/warehouse/test' | | TBLPROPERTIES ('numFiles'='3', 'COLUMN_STATS_ACCURATE'='true', 'numRows'='9', 'totalSize'='40', 'rawDataSize'='31') | +---------------------------------------------------------------------------------------------------------------------+ ... View more

Hi, As the error message indicated, UNION ALL is not supported at top level, you need to put it in a sub query, similar to below: SELECT loc, cnt FROM ( select a.loc as loc, a.cnt13 cnt from crimeloc13 a UNION ALL select b.loc as loc, b.cnt14 as cnt from crimeloc14 b ) a; ... View more