Fix two libpq leak bugs on COPY error paths (1.5) - #556
Merged
Conversation
This is a backport of the PR duckdb#555 to `v1.5-variegata` stable branch. PostgresBinaryReader::FetchNextBuffer() leaked the PQgetCopyData buffer when the message was shorter than the tuple count it has to contain. PQgetCopyData allocates even when it hands back a length we cannot use, and buffer was only assigned after the check, so FreeBuffer() never saw it. Assign it first and let the existing ownership do the freeing. The three COPY error paths passed a possibly null PGresult to PQresultErrorMessage(). libpq returns an empty string rather than crashing, which is how "Failed to copy data: " with no reason after it gets produced. A null result means the connection failed, so report PQerrorMessage() in that case - the same pattern ExecuteQueries() and PostgresQueryBind() already use. Reported as Snowflake-Labs/pg_lake#415.
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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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 check back later.
This is a backport of the PR #555 to
v1.5-variegatastable branch.PostgresBinaryReader::FetchNextBuffer() leaked the PQgetCopyData buffer when the message was shorter than the tuple count it has to contain. PQgetCopyData allocates even when it hands back a length we cannot use, and buffer was only assigned after the check, so FreeBuffer() never saw it. Assign it first and let the existing ownership do the freeing.
The three COPY error paths passed a possibly null PGresult to PQresultErrorMessage(). libpq returns an empty string rather than crashing, which is how "Failed to copy data: " with no reason after it gets produced. A null result means the connection failed, so report PQerrorMessage() in that case - the same pattern ExecuteQueries() and PostgresQueryBind() already use.
Reported as Snowflake-Labs/pg_lake#415.