[xs64bit] CA-134765: Fix race condition in database layer #1746
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The read_records_where function in the database layer (used by the get_all_records and get_all_records_where APIs) was reading the database multiple times by calling find_refs_with_filter[1] to get the refs that matched the query and then calling read_record[2] for each of these refs. This violates point #2 of the locking strategy stated at the top of the module that read only functions must only call get_database once to ensure they operate on a consistent snapshot. Since [1] and [2] make get_database calls the get_all_records* functions make n+1 calls to get_database for a table with n records. Because of this, deleting a record during a get_all_records_where will result in a DBCache_NotFound exception with parameter "missing row". This commits adds internal variants of functions [1] and [2] that take an actual instance of Database.t rather than a Db_ref.t which is a Database.t ref ref. Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
johnelse
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May 13, 2014
[xs64bit] CA-134765: Fix race condition in database layer
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Backport of #1745.