[H5vz3qhy] Prevent cascade trigger transactions #346
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ncordon
reviewed
Mar 15, 2023
| @@ -35,6 +35,7 @@ | |||
| public class TriggerHandler extends LifecycleAdapter implements TransactionEventListener<Void> { | |||
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| private enum Phase {before, after, rollback, afterAsync} | |||
| private static final Map<String, Object> TRIGGER_META = Map.of("trigger", true); | |||
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Map.of("apoc.trigger", true) would be better in my opinion. Just in case people start seeing things in their transactions they don't know where they came from, that's more self explanatory than just trigger
ncordon
reviewed
Mar 15, 2023
Comment on lines
207
to
209
| // if `txData.metaData()` is equal to TRIGGER_META, it means that the transaction | ||
| // if it is equal, it means that the transaction comes from another TriggerHandler transaction, | ||
| // therefore the execution must be blocked to prevent a deadlock due to cascading transactions |
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Suggested change
| // if `txData.metaData()` is equal to TRIGGER_META, it means that the transaction | |
| // if it is equal, it means that the transaction comes from another TriggerHandler transaction, | |
| // therefore the execution must be blocked to prevent a deadlock due to cascading transactions | |
| // if `txData.metaData()` is equal to TRIGGER_META, it means that the transaction | |
| // comes from another TriggerHandler transaction, | |
| // therefore the execution must be blocked to prevent a deadlock due to cascading transactions |
ncordon
reviewed
Mar 15, 2023
| // if it is equal, it means that the transaction comes from another TriggerHandler transaction, | ||
| // therefore the execution must be blocked to prevent a deadlock due to cascading transactions | ||
| Map<String, Object> metaData = txData.metaData(); | ||
| if (metaData.equals(TRIGGER_META)) { |
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This is personal preference but if you extract this block outside to a function:
public Boolean isTransactionCreatedByTrigger(TransactionData txData) {
Map<String, Object> metaData = txData.metaData();
return metaData.equals(TRIGGER_META);
}
then this method becomes more self-documented
ncordon
approved these changes
Mar 15, 2023
vga91
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to neo4j-contrib/neo4j-apoc-procedures
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Mar 30, 2023
* [H5vz3qhy] Prevent cascade trigger transactions * [H5vz3qhy] Changed flaky test * [H5vz3qhy] Small changes review
vga91
added a commit
to neo4j-contrib/neo4j-apoc-procedures
that referenced
this pull request
Mar 30, 2023
* [H5vz3qhy] Prevent cascade trigger transactions * [H5vz3qhy] Changed flaky test * [H5vz3qhy] Small changes review
vga91
added a commit
to neo4j-contrib/neo4j-apoc-procedures
that referenced
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Apr 4, 2023
* [H5vz3qhy] Prevent cascade trigger transactions * [H5vz3qhy] Changed flaky test * [H5vz3qhy] Small changes review
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Added a
CALL tx.setMetaData(<TRIGGER_META>)procedure in transactions with phaseafterandafterAsync,in order to prevent cascade trigger transactions coming from
TriggerHandleritself,so that we can avoid some deadlock conditions.
I don't know if it is somehow directly related to this pr,
but I had to change the
testRemoveNodetoo,because it sometimes failed as the previous
CREATE (f:Foo)had id = 0.