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HPCC-31530 Remove stale LZ groups #18458

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jakesmith
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@jakesmith jakesmith commented Mar 27, 2024

Remove existing Dali LZ groups before creating groups from the environment or storage planes.
This avoids stale groups being left behind, which in-turn can cause systems to spuriously see them and try to reference nodes that no longer exist, causing stalls and delays to be introduced.

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@jakesmith jakesmith requested a review from ghalliday March 27, 2024 13:04
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@jakesmith looks like a good change. A couple of suggestions for improving reuse/optimizing it.

throw makeStringException(0, "CInitGroups::clearLZGroups called in read-only mode");
IPropertyTree *root = groupsconnlock.conn->queryRoot();
std::vector<Owned<IPropertyTree>> toDelete;
Owned<IPropertyTreeIterator> groups = root->getElements("Group[@kind='dropzone']");
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root->removeElements().. might be quite a useful function - even if it was implemented with this code, rather than being optimized. (That could come later.)
I had a quick search, and there are quite a few chunks of code that follow this pattern (e.g. addJsonPublicService), but there are also several that remove the tree within the iterator. Will that work? (E.g. removeEclHiddenStructs)

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are also several that remove the tree within the iterator. Will that work? (E.g. removeEclHiddenStructs)

I think it should work, the iterators link elements, or continue to use ptrees + xpaths, but I wouldn't advise deleting items from an active iterator.

Good idea to enter a dedicated method, but it and refactoring code that uses it, yes in a new PR. I'll open a JIRA.

if (!writeLock)
throw makeStringException(0, "CInitGroups::clearLZGroups called in read-only mode");
IPropertyTree *root = groupsconnlock.conn->queryRoot();
std::vector<Owned<IPropertyTree>> toDelete;
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A vector of IPropertyTree * and iter->query() would avoid linking and releasing the tree items.

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agreed, I'll change it.

@jakesmith jakesmith requested a review from ghalliday March 28, 2024 16:57
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@ghalliday - please see new commit. Let me know if you are happy for me to squash it.

Remove existing Dali LZ groups before creating groups from
the environment or storage planes.
This avoids stale groups being left behind, which in-turn can
cause systems to spuriously see them and try to reference
nodes that no longer exist, causing stalls and delays to be
introduced.

Signed-off-by: Jake Smith <[email protected]>
@jakesmith jakesmith force-pushed the HPCC-31530-clearup-stale-lz-groups branch from 3722612 to 8ce96c9 Compare March 28, 2024 17:45
@ghalliday ghalliday merged commit ca74c00 into hpcc-systems:candidate-9.4.x Mar 28, 2024
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2 participants