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https://issues.apache.org/jira/browse/FLINK-33365?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17784915#comment-17784915
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david radley edited comment on FLINK-33365 at 11/10/23 12:29 PM:
-----------------------------------------------------------------
an update on what I have found:
I have switched on DEBUG put out the rules that are being driven for my
recreation. I see :
org.apache.flink.table.planner.plan.optimize.program.FlinkChainedProgram [] -
optimize time_indicator cost 1 ms.
optimize result:
FlinkLogicalSink(table=[*anonymous_collect$4*], fields=[ip, proctime, ip0,
type])
+- FlinkLogicalCalc(select=[ip, PROCTIME_MATERIALIZE(proctime) AS proctime,
ip0, type])
+- FlinkLogicalJoin(condition=[=($0, $4)], joinType=[left])
:- FlinkLogicalCalc(select=[ip, PROCTIME() AS proctime])
: +- FlinkLogicalTableSourceScan(table=[[paimon_catalog, default, a]],
fields=[ip])
+- FlinkLogicalSnapshot(period=[$cor0.proctime])
+- FlinkLogicalCalc(select=[ip, CAST(0 AS INTEGER) AS type, CAST(ip AS
VARCHAR(2147483647) CHARACTER SET "UTF-16LE") AS ip0])
+- FlinkLogicalTableSourceScan(table=[[mariadb_catalog, menagerie,
c, {*}filter=[=(type, 0)]]]{*}, fields=[ip, type])
Is changed in the next rule to
org.apache.flink.table.planner.plan.optimize.program.FlinkChainedProgram [] -
optimize physical cost 3 ms.
optimize result:
Sink(table=[*anonymous_collect$4*], fields=[ip, proctime, ip0, type])
+- Calc(select=[ip, PROCTIME_MATERIALIZE(proctime) AS proctime, ip0, type])
+- LookupJoin(table=[mariadb_catalog.menagerie.c], joinType=[LeftOuterJoin],
lookup=[ip=ip], select=[ip, proctime, ip, *CAST(0 AS INTEGER)* AS type, CAST(ip
AS VARCHAR(2147483647) CHARACTER SET "UTF-16LE") AS ip0])
+- Calc(select=[ip, PROCTIME() AS proctime])
+- TableSourceScan(table=[[paimon_catalog, default, a]], fields=[ip])
The *CAST(0 AS INTEGER)* is in the final Optimized Execution Plan we see in the
explain.
I am not an expert at this, but it seems to me that either 2 things are
happening:
1) This change to the graph is a valid optimization but it is not being
actioned properly when executed, such that the CAST(0 AS INTEGER) is ignored.
or
2) the comments at the top of
[CommonPhysicalLookupJoin.scala]([https://github.com/apache/flink/blob/master/flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/planner/plan/nodes/physical/common/CommonPhysicalLookupJoin.scala)]
are correct and this filter should actually be in the lookup keys. The
comments says
_* For a lookup join query:_
_*_
_* <pre> SELECT T.id, T.content, D.age FROM T JOIN userTable FOR SYSTEM_TIME AS
OF T.proctime AS D_
_* ON T.content = concat(D.name, '!') AND D.age = 11 AND T.id = D.id WHERE
D.name LIKE 'Jack%'_
_* </pre>_
_*_
_* The LookupJoin physical node encapsulates the following RelNode tree:_
_*_
_* <pre> Join (l.name = r.name) / \ RelNode Calc (concat(name, "!") as name,
name LIKE 'Jack%') |_
_* DimTable (lookup-keys: age=11, id=l.id) (age, id, name) </pre>_
_*_
_* The important member fields in LookupJoin: <ul> <li>allLookupKeys: [$0=11,
$1=l.id] ($0 and $1 is_
_* the indexes of age and id in dim table)</li> <li>remainingCondition:
l.name=r.name</li> <ul>_
_*_
_* The workflow of lookup join:_
_*_
_* 1) lookup records dimension table using the lookup-keys <br> 2) project &
filter on the lookup-ed_
_* records <br> 3) join left input record and lookup-ed records <br> 4) only
outputs the rows which_
_* match to the remainingCondition <br>_
was (Author: JIRAUSER300523):
an update on what I have found:
I have switched on DEBUG put out the rules that are being driven for my
recreation. I see :
org.apache.flink.table.planner.plan.optimize.program.FlinkChainedProgram [] -
optimize time_indicator cost 1 ms.
optimize result:
FlinkLogicalSink(table=[*anonymous_collect$4*], fields=[ip, proctime, ip0,
type])
+- FlinkLogicalCalc(select=[ip, PROCTIME_MATERIALIZE(proctime) AS proctime,
ip0, type])
+- FlinkLogicalJoin(condition=[=($0, $4)], joinType=[left])
:- FlinkLogicalCalc(select=[ip, PROCTIME() AS proctime])
: +- FlinkLogicalTableSourceScan(table=[[paimon_catalog, default, a]],
fields=[ip])
+- FlinkLogicalSnapshot(period=[$cor0.proctime])
+- FlinkLogicalCalc(select=[ip, CAST(0 AS INTEGER) AS type, CAST(ip AS
VARCHAR(2147483647) CHARACTER SET "UTF-16LE") AS ip0])
+- FlinkLogicalTableSourceScan(table=[[mariadb_catalog, menagerie,
c, {*}filter=[=(type, 0)]]]{*}, fields=[ip, type])
Is changed in the next rule to
org.apache.flink.table.planner.plan.optimize.program.FlinkChainedProgram [] -
optimize physical cost 3 ms.
optimize result:
Sink(table=[*anonymous_collect$4*], fields=[ip, proctime, ip0, type])
+- Calc(select=[ip, PROCTIME_MATERIALIZE(proctime) AS proctime, ip0, type])
+- LookupJoin(table=[mariadb_catalog.menagerie.c], joinType=[LeftOuterJoin],
lookup=[ip=ip], select=[ip, proctime, ip, *CAST(0 AS INTEGER)* AS type, CAST(ip
AS VARCHAR(2147483647) CHARACTER SET "UTF-16LE") AS ip0])
+- Calc(select=[ip, PROCTIME() AS proctime])
+- TableSourceScan(table=[[paimon_catalog, default, a]], fields=[ip])
The *CAST(0 AS INTEGER)* is in the final Optimized Execution Plan we see in the
explain.
I am not an expert at this, but it seems to me that either 2 things are
happening:
1) This change to the graph is a valid optimization but it is not being
actioned properly when executed, such that the CAST(0 AS INTEGER) is ignored **
or
2) the comments at the top of
[CommonPhysicalLookupJoin.scala]([https://github.com/apache/flink/blob/master/flink-table/flink-table-planner/src/main/scala/org/apache/flink/table/planner/plan/nodes/physical/common/CommonPhysicalLookupJoin.scala)]
are correct and this filter should actually be in the lookup keys. The
comments says
_* For a lookup join query:_
_*_
_* <pre> SELECT T.id, T.content, D.age FROM T JOIN userTable FOR SYSTEM_TIME AS
OF T.proctime AS D_
_* ON T.content = concat(D.name, '!') AND D.age = 11 AND T.id = D.id WHERE
D.name LIKE 'Jack%'_
_* </pre>_
_*_
_* The LookupJoin physical node encapsulates the following RelNode tree:_
_*_
_* <pre> Join (l.name = r.name) / \ RelNode Calc (concat(name, "!") as name,
name LIKE 'Jack%') \|_
_* DimTable (lookup-keys: age=11, id=l.id) (age, id, name) </pre>_
_*_
_* The important member fields in LookupJoin: <ul> <li>allLookupKeys: [$0=11,
$1=l.id] ($0 and $1 is_
_* the indexes of age and id in dim table)</li> <li>remainingCondition:
l.name=r.name</li> <ul>_
_*_
_* The workflow of lookup join:_
_*_
_* 1) lookup records dimension table using the lookup-keys <br> 2) project &
filter on the lookup-ed_
_* records <br> 3) join left input record and lookup-ed records <br> 4) only
outputs the rows which_
_* match to the remainingCondition <br>_
> Missing filter condition in execution plan containing lookup join with mysql
> jdbc connector
> -------------------------------------------------------------------------------------------
>
> Key: FLINK-33365
> URL: https://issues.apache.org/jira/browse/FLINK-33365
> Project: Flink
> Issue Type: Bug
> Components: Connectors / JDBC
> Affects Versions: 1.18.0, 1.17.1
> Environment: Flink 1.17.1 & Flink 1.18.0 with
> flink-connector-jdbc-3.1.1-1.17.jar
> Reporter: macdoor615
> Assignee: david radley
> Priority: Critical
> Attachments: flink-connector-jdbc-3.0.0-1.16.png,
> flink-connector-jdbc-3.1.1-1.17.png
>
>
> create table in flink with sql-client.sh
> {code:java}
> CREATE TABLE default_catalog.default_database.a (
> ip string,
> proctime as proctime()
> )
> WITH (
> 'connector' = 'datagen'
> );{code}
> create table in mysql
> {code:java}
> create table b (
> ip varchar(20),
> type int
> ); {code}
>
> Flink 1.17.1/ 1.18.0 and *flink-connector-jdbc-3.1.1-1.17.jar*
> excute in sql-client.sh
> {code:java}
> explain SELECT * FROM default_catalog.default_database.a left join
> bnpmp_mysql_test.gem_tmp.b FOR SYSTEM_TIME AS OF a.proctime on b.type = 0 and
> a.ip = b.ip; {code}
> get the execution plan
> {code:java}
> ...
> == Optimized Execution Plan ==
> Calc(select=[ip, PROCTIME_MATERIALIZE(proctime) AS proctime, ip0, type])
> +- LookupJoin(table=[bnpmp_mysql_test.gem_tmp.b], joinType=[LeftOuterJoin],
> lookup=[ip=ip], select=[ip, proctime, ip, CAST(0 AS INTEGER) AS type, CAST(ip
> AS VARCHAR(2147483647)) AS ip0])
> +- Calc(select=[ip, PROCTIME() AS proctime])
> +- TableSourceScan(table=[[default_catalog, default_database, a]],
> fields=[ip]){code}
>
> excute same sql in sql-client with Flink 1.17.1/ 1.18.0 and
> *flink-connector-jdbc-3.0.0-1.16.jar*
> get the execution plan
> {code:java}
> ...
> == Optimized Execution Plan ==
> Calc(select=[ip, PROCTIME_MATERIALIZE(proctime) AS proctime, ip0, type])
> +- LookupJoin(table=[bnpmp_mysql_test.gem_tmp.b], joinType=[LeftOuterJoin],
> lookup=[type=0, ip=ip], where=[(type = 0)], select=[ip, proctime, ip, CAST(0
> AS INTEGER) AS type, CAST(ip AS VARCHAR(2147483647)) AS ip0])
> +- Calc(select=[ip, PROCTIME() AS proctime])
> +- TableSourceScan(table=[[default_catalog, default_database, a]],
> fields=[ip]) {code}
> with flink-connector-jdbc-3.1.1-1.17.jar, the condition is
> *lookup=[ip=ip]*
> with flink-connector-jdbc-3.0.0-1.16.jar , the condition is
> *lookup=[type=0, ip=ip], where=[(type = 0)]*
>
> In out real world production environment, this lead incorrect data output
>
>
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