079480dc20
This commit adjusts RangeVarCallbackForReindexIndex() to handle an extremely unlikely race condition involving concurrent OID reuse. In short, if REINDEX INDEX is executed at the same time that the index is re-created with the same name and OID but a different parent table OID, we might lock the wrong parent table. To fix, simply detect when this happens and emit an ERROR. Unfortunately, we can't gracefully handle this situation because we will have already locked the index, and we must lock the parent table before the index to avoid deadlocks. While at it, I've replaced all but one early return in this callback function with ERRORs that should be unreachable. While I haven't verified the presence of a live bug, the checks in question appear to be unnecessary, and the early returns seem prone to breaking the parent table locking code in subtle ways. If nothing else, this simplifies the code a bit. This is a bug fix and could be back-patched, but given the presumed rarity of the race condition and the lack of reports, I'm not going to bother. Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Jeff Davis <pgsql@j-davis.com> Discussion: https://postgr.es/m/Z8zwVmGzXyDdkAXj%40nathan
PostgreSQL Database Management System
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