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10-10-2018
6
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3
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3
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My Accepted Solutions
Title | Views | Posted |
---|---|---|
1359 | 05-15-2020 12:45 PM | |
1783 | 03-14-2019 11:46 AM | |
2925 | 02-13-2019 12:04 PM |
05-15-2020
12:45 PM
Impala only looks for updates to the config values to a pool when a query is submitted to it. The changes that you made in Cloudera manager would have been propagated to all the Impalads. So the first query that you submit to that pool will use the updated configs and you ll see them updated on the admission control debug webpage as well.
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03-14-2019
11:46 AM
1 Kudo
the property "llama.am.throttling.maximum.placed.reservations.root.*" places a limit on the total number of queries across the cluster. So in this case you can only run 4 overall
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03-05-2019
04:20 PM
For non-equi joins, we use only NESTED LOOP JOIN. But for your use case, if you are only concerned with equivalence of the first 7 letters in the string 'full_id'. Then you can convert it into an equality predicate by doing something like : strleft(t1.full_id, 7) = strleft(t2.full_id, 7) So the plan for the new query would result in a hash join, which can be faster for your case. select count(*) from test_like t1 left join test_like t2 on strleft(t1.full_id, 7) = strleft(t2.full_id, 7) +------------------------------------------------------------------------------------+ |
| PLAN-ROOT SINK |
| | |
| 06:AGGREGATE [FINALIZE] |
| | output: count:merge(*) |
| | row-size=8B cardinality=1 |
| | |
| 05:EXCHANGE [UNPARTITIONED] |
| | |
| 03:AGGREGATE |
| | output: count(*) |
| | row-size=8B cardinality=1 |
| | |
| 02:HASH JOIN [LEFT OUTER JOIN, BROADCAST] |
| | hash predicates: strleft(t1.full_id, 7) = strleft(t2.full_id, 7) |
| | row-size=30B cardinality=unavailable |
| | |
| |--04:EXCHANGE [BROADCAST] |
| | | |
| | 01:SCAN KUDU [bik.test_like t2] |
| | row-size=15B cardinality=unavailable |
| | |
| 00:SCAN KUDU [bik.test_like t1] |
| row-size=15B cardinality=unavailable |
+------------------------------------------------------------------------------------+
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02-13-2019
12:04 PM
2 Kudos
CM collects all the metrics from impala which are also available through the impala debug page. Please take a look at the metrics mentioned here which you can use in CM to create graphs. Specifically "Impala Daemon Resource Pool Metrics" which you can use to create the graph for your use case that displays the number of running queries as follows: Graph that displays the aggregate num of running queries for a pool across the cluster: select total_impala_admission_controller_local_num_admitted_running_across_impala_daemon_pools WHERE poolName="root.<your_pool_name>" Graph that displays the num of running queries submitted to a particular host for a pool: select impala_admission_controller_local_num_admitted_running WHERE poolName="root.<your_pool_name>" and hostname="<host_address>" You can further tweak these queries and explore the chart builder in CM to get the exact graph you want.
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10-10-2018
01:30 PM
The MEM_LIMIT is a hard limit on the amount of memory that can be used by the query and cannot be re-negotiated during execution. If the default mem_limit that you set does not suffice, you can either increase it OR you can set the mem_limit query option to a higher value only for that query.
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