Details
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Improvement
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Status: Resolved
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Major
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Resolution: Fixed
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Impala 4.0.0
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None
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ghx-label-8
Description
In Impala 4.0, setting a very high BATCH_SIZE or near max limit of 65536 can cause some fragment's memory usage to spike way past the query's defined MEM_LIMIT or pool's Maximum Query Memory Limit with Clamp on. So even though MEM_LIMIT is set reasonable, the query can still fail with out of memory and a huge amount of memory used on fragment. Reducing BATCH_SIZE to a reasonable amount or back to default will allow the query to run without issue and use reasonable amount of memory within query's MEM_LIMIT or pool's Maximum Query Memory Limit.
1) set BATCH_SIZE=65536; set MEM_LIMIT=1g;
Query State: EXCEPTION
Impala Query State: ERROR
Query Status: Memory limit exceeded: Error occurred on backend ...:27000 by fragment ... Memory left in process limit: 145.53 GB Memory left in query limit: -6.80 GB Query(...): memory limit exceeded. Limit=1.00 GB Reservation=86.44 MB ReservationLimit=819.20 MB OtherMemory=7.71 GB Total=7.80 GB Peak=7.84 GB Unclaimed reservations: Reservation=8.50 MB OtherMemory=0 Total=8.50 MB Peak=56.44 MB Runtime Filter Bank: Reservation=4.00 MB ReservationLimit=4.00 MB OtherMemory=0 Total=4.00 MB Peak=4.00 MB Fragment ...: Reservation=1.94 MB OtherMemory=7.59 GB Total=7.59 GB Peak=7.63 GB HASH_JOIN_NODE (id=8): Reservation=1.94 MB OtherMemory=7.57 GB Total=7.57 GB Peak=7.57 GB Exprs: Total=7.57 GB Peak=7.57 GB Hash Join Builder (join_node_id=8): Total=0 Peak=1.95 MB
...
Query Options (set by configuration): BATCH_SIZE=65536,MEM_LIMIT=1073741824,CLIENT_IDENTIFIER=Impala Shell v4.0.0.7.2.16.0-287 (5ae3917) built on Mon Jan 9 21:23:59 UTC 2023,DEFAULT_FILE_FORMAT=PARQUET,...
...
ExecSummary:
...
09:AGGREGATE 32 32 0.000ns 0.000ns 0 4.83M 36.31 MB 212.78 MB STREAMING
08:HASH JOIN 32 32 5s149ms 2m44s 0 194.95M 7.57 GB 1.94 MB RIGHT OUTER JOIN, PARTITIONED
|--18:EXCHANGE 32 32 93.750us 1.000ms 10.46K 1.55K 1.65 MB 2.56 MB HASH(...
2) set BATCH_SIZE=0; set MEM_LIMIT=1g;
Query State: FINISHED
Impala Query State: FINISHED
...
Query Options (set by configuration and planner): MEM_LIMIT=1073741824,CLIENT_IDENTIFIER=Impala Shell v4.0.0.7.2.16.0-287 (5ae3917) built on Mon Jan 9 21:23:59 UTC 2023,DEFAULT_FILE_FORMAT=PARQUET,...
...
ExecSummary:
...
09:AGGREGATE 32 32 593.748us 18.999ms 45 4.83M 34.06 MB 212.78 MB STREAMING
08:HASH JOIN 32 32 10s873ms 5m47s 10.47K 194.95M 123.48 MB 1.94 MB RIGHT OUTER JOIN, PARTITIONED
|--18:EXCHANGE 32 32 0.000ns 0.000ns 10.46K 1.55K 344.00 KB 1.69 MB HASH(...