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Posted to issues-all@impala.apache.org by "Tim Armstrong (JIRA)" <ji...@apache.org> on 2018/08/16 20:50:00 UTC
[jira] [Updated] (IMPALA-7293) Show tuple layout in explain plan
[ https://issues.apache.org/jira/browse/IMPALA-7293?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Tim Armstrong updated IMPALA-7293:
----------------------------------
Description:
There's currently no way to tell in the explain plan what the contents of each tuple are. At explain_level>=2 we include "tuple-ids" but no information about what is actually in the tuples.
{noformat}
[localhost:21000] default> explain select min(regexp_replace(l_comment, ".", "x"))
from tpch.lineitem; summary;
Query: explain select min(regexp_replace(l_comment, ".", "x"))
from tpch.lineitem
+---------------------------------------------------------------------------------------+
| Explain String |
+---------------------------------------------------------------------------------------+
| Max Per-Host Resource Reservation: Memory=8.00MB Threads=3 |
| Per-Host Resource Estimates: Memory=284.00MB |
| |
| F01:PLAN FRAGMENT [UNPARTITIONED] hosts=1 instances=1 |
| | Per-Host Resources: mem-estimate=10.00MB mem-reservation=0B thread-reservation=1 |
| PLAN-ROOT SINK |
| | mem-estimate=0B mem-reservation=0B thread-reservation=0 |
| | |
| 03:AGGREGATE [FINALIZE] |
| | output: min:merge(regexp_replace(l_comment, '.', 'x')) |
| | mem-estimate=10.00MB mem-reservation=0B spill-buffer=2.00MB thread-reservation=0 |
| | tuple-ids=1 row-size=16B cardinality=1 |
| | |
| 02:EXCHANGE [UNPARTITIONED] |
| | mem-estimate=0B mem-reservation=0B thread-reservation=0 |
| | tuple-ids=1 row-size=16B cardinality=1 |
| | |
| F00:PLAN FRAGMENT [RANDOM] hosts=3 instances=3 |
| Per-Host Resources: mem-estimate=274.00MB mem-reservation=8.00MB thread-reservation=2 |
| 01:AGGREGATE |
| | output: min(regexp_replace(l_comment, '.', 'x')) |
| | mem-estimate=10.00MB mem-reservation=0B spill-buffer=2.00MB thread-reservation=0 |
| | tuple-ids=1 row-size=16B cardinality=1 |
| | |
| 00:SCAN HDFS [tpch.lineitem, RANDOM] |
| partitions=1/1 files=1 size=718.94MB |
| stored statistics: |
| table: rows=6001215 size=718.94MB |
| columns: all |
| extrapolated-rows=disabled max-scan-range-rows=1068457 |
| mem-estimate=264.00MB mem-reservation=8.00MB thread-reservation=1 |
| tuple-ids=0 row-size=42B cardinality=6001215 |
+---------------------------------------------------------------------------------------+
Fetched 32 row(s) in 0.01s
Summary not available
{noformat}
We already have a debugString() methods that prints a human-readable representation. We could start off by printing a tuple descriptor per line at the end of the explain plan and tweaking it a little where necessary to make it more readable, e.g. hiding non-materialized slots.
was:
There's currently no way to tell in the explain plan what the contents of each tuple are. At explain_level>=2 we include "tuple-ids" but no information about what is actually in the tuples.
{noformat}
[localhost:21000] default> explain select min(regexp_replace(l_comment, ".", "x"))
from tpch.lineitem; summary;
Query: explain select min(regexp_replace(l_comment, ".", "x"))
from tpch.lineitem
+---------------------------------------------------------------------------------------+
| Explain String |
+---------------------------------------------------------------------------------------+
| Max Per-Host Resource Reservation: Memory=8.00MB Threads=3 |
| Per-Host Resource Estimates: Memory=284.00MB |
| |
| F01:PLAN FRAGMENT [UNPARTITIONED] hosts=1 instances=1 |
| | Per-Host Resources: mem-estimate=10.00MB mem-reservation=0B thread-reservation=1 |
| PLAN-ROOT SINK |
| | mem-estimate=0B mem-reservation=0B thread-reservation=0 |
| | |
| 03:AGGREGATE [FINALIZE] |
| | output: min:merge(regexp_replace(l_comment, '.', 'x')) |
| | mem-estimate=10.00MB mem-reservation=0B spill-buffer=2.00MB thread-reservation=0 |
| | tuple-ids=1 row-size=16B cardinality=1 |
| | |
| 02:EXCHANGE [UNPARTITIONED] |
| | mem-estimate=0B mem-reservation=0B thread-reservation=0 |
| | tuple-ids=1 row-size=16B cardinality=1 |
| | |
| F00:PLAN FRAGMENT [RANDOM] hosts=3 instances=3 |
| Per-Host Resources: mem-estimate=274.00MB mem-reservation=8.00MB thread-reservation=2 |
| 01:AGGREGATE |
| | output: min(regexp_replace(l_comment, '.', 'x')) |
| | mem-estimate=10.00MB mem-reservation=0B spill-buffer=2.00MB thread-reservation=0 |
| | tuple-ids=1 row-size=16B cardinality=1 |
| | |
| 00:SCAN HDFS [tpch.lineitem, RANDOM] |
| partitions=1/1 files=1 size=718.94MB |
| stored statistics: |
| table: rows=6001215 size=718.94MB |
| columns: all |
| extrapolated-rows=disabled max-scan-range-rows=1068457 |
| mem-estimate=264.00MB mem-reservation=8.00MB thread-reservation=1 |
| tuple-ids=0 row-size=42B cardinality=6001215 |
+---------------------------------------------------------------------------------------+
Fetched 32 row(s) in 0.01s
Summary not available
{noformat}
> Show tuple layout in explain plan
> ---------------------------------
>
> Key: IMPALA-7293
> URL: https://issues.apache.org/jira/browse/IMPALA-7293
> Project: IMPALA
> Issue Type: Improvement
> Components: Frontend
> Reporter: Tim Armstrong
> Priority: Major
> Labels: observability
>
> There's currently no way to tell in the explain plan what the contents of each tuple are. At explain_level>=2 we include "tuple-ids" but no information about what is actually in the tuples.
> {noformat}
> [localhost:21000] default> explain select min(regexp_replace(l_comment, ".", "x"))
> from tpch.lineitem; summary;
> Query: explain select min(regexp_replace(l_comment, ".", "x"))
> from tpch.lineitem
> +---------------------------------------------------------------------------------------+
> | Explain String |
> +---------------------------------------------------------------------------------------+
> | Max Per-Host Resource Reservation: Memory=8.00MB Threads=3 |
> | Per-Host Resource Estimates: Memory=284.00MB |
> | |
> | F01:PLAN FRAGMENT [UNPARTITIONED] hosts=1 instances=1 |
> | | Per-Host Resources: mem-estimate=10.00MB mem-reservation=0B thread-reservation=1 |
> | PLAN-ROOT SINK |
> | | mem-estimate=0B mem-reservation=0B thread-reservation=0 |
> | | |
> | 03:AGGREGATE [FINALIZE] |
> | | output: min:merge(regexp_replace(l_comment, '.', 'x')) |
> | | mem-estimate=10.00MB mem-reservation=0B spill-buffer=2.00MB thread-reservation=0 |
> | | tuple-ids=1 row-size=16B cardinality=1 |
> | | |
> | 02:EXCHANGE [UNPARTITIONED] |
> | | mem-estimate=0B mem-reservation=0B thread-reservation=0 |
> | | tuple-ids=1 row-size=16B cardinality=1 |
> | | |
> | F00:PLAN FRAGMENT [RANDOM] hosts=3 instances=3 |
> | Per-Host Resources: mem-estimate=274.00MB mem-reservation=8.00MB thread-reservation=2 |
> | 01:AGGREGATE |
> | | output: min(regexp_replace(l_comment, '.', 'x')) |
> | | mem-estimate=10.00MB mem-reservation=0B spill-buffer=2.00MB thread-reservation=0 |
> | | tuple-ids=1 row-size=16B cardinality=1 |
> | | |
> | 00:SCAN HDFS [tpch.lineitem, RANDOM] |
> | partitions=1/1 files=1 size=718.94MB |
> | stored statistics: |
> | table: rows=6001215 size=718.94MB |
> | columns: all |
> | extrapolated-rows=disabled max-scan-range-rows=1068457 |
> | mem-estimate=264.00MB mem-reservation=8.00MB thread-reservation=1 |
> | tuple-ids=0 row-size=42B cardinality=6001215 |
> +---------------------------------------------------------------------------------------+
> Fetched 32 row(s) in 0.01s
> Summary not available
> {noformat}
> We already have a debugString() methods that prints a human-readable representation. We could start off by printing a tuple descriptor per line at the end of the explain plan and tweaking it a little where necessary to make it more readable, e.g. hiding non-materialized slots.
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