pglogical_drop_node should release the LWLock it acquires #3
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Failing to release these locks causes subsequent acquires for exclusive access to fail. This can be reproduced with the following steps: Create a provider node Drop the node Recreate the node Create a subscription to that node That subscription will never be able to complete the sync because it will be blocked while trying to acquire the ReplicationSlotControlLock in exclusive mode while creating the replication slot on the provider
|
Was able to verify this fix with newly built rpms. |
|
Also, I'm not sure of a good workaround for this. It feels like the postgres service on the provider would have to be restarted to release the locks, but something less heavy handed would be nice. |
|
BTW, there's now a public repo at https://github.com/2ndQuadrant/pglogical |
|
Yeah I also have a PR open there. @ringerc If there are other changes I want to contribute, where should I go with them first? Here or https://github.com/2ndQuadrant/pglogical? I made this PR in both places because I found the pglogical repo after I had already created this one. |
ringerc
pushed a commit
that referenced
this pull request
Sep 11, 2018
refresh_by_match_merge() has some issues in the way it builds a SQL query to construct the "diff" table: 1. It doesn't require the selected unique index(es) to be indimmediate. 2. It doesn't pay attention to the particular equality semantics enforced by a given index, but just assumes that they must be those of the column datatype's default btree opclass. 3. It doesn't check that the indexes are btrees. 4. It's insufficiently careful to ensure that the parser will pick the intended operator when parsing the query. (This would have been a security bug before CVE-2018-1058.) 5. It's not careful about indexes on system columns. The way to fix postgres#4 is to make use of the existing code in ri_triggers.c for generating an arbitrary binary operator clause. I chose to move that to ruleutils.c, since that seems a more reasonable place to be exporting such functionality from than ri_triggers.c. While #1, #3, and postgres#5 are just latent given existing feature restrictions, and #2 doesn't arise in the core system for lack of alternate opclasses with different equality behaviors, postgres#4 seems like an issue worth back-patching. That's the bulk of the change anyway, so just back-patch the whole thing to 9.4 where this code was introduced. Discussion: https://postgr.es/m/13836.1521413227@sss.pgh.pa.us
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please ch
2B99
eck back later.
Failing to release these locks causes subsequent acquires for exclusive access to fail.
This can be reproduced with the following steps:
That subscription will never be able to complete the sync because it will be blocked while trying to acquire the ReplicationSlotControlLock in exclusive mode while creating the replication slot on the provider
cc @ringerc
I'll make this change locally and rebuild my rpms to verify the fix.