Prevent race condition while reading relmapper file. Contrary to the comment here, POSIX does not guarantee atomicity of a read(), if another process calls write() concurrently. Or at least Linux does not. Add locking to load_relmap_file() to avoid the race condition.
Fixes bug #17064. Thanks to Alexander Lakhin for the report and test case. Backpatch-through: 9.6, all supported versions. Discussion: https://www.postgresql.org/message-id/[email protected] Branch ------ REL_10_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/a5eacd86b71542d5e377d1fef628866dae859809 Modified Files -------------- src/backend/utils/cache/relmapper.c | 34 ++++++++++++++++++++-------------- 1 file changed, 20 insertions(+), 14 deletions(-)
