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34a947ca13
Sometimes it happens that the visibility information for a tuple becomes corrupted, either due to bugs in the database software or external factors. Provide a function heap_force_kill() that can be used to truncate such dead tuples to dead line pointers, and a function heap_force_freeze() that can be used to overwrite the visibility information in such a way that the tuple becomes all-visible. These functions are unsafe, in that you can easily use them to corrupt a database that was not previously corrupted, and you can use them to further corrupt an already-corrupted database or to destroy data. The documentation accordingly cautions against casual use. However, in some cases they permit recovery of data that would otherwise be very difficult to recover, or to allow a system to continue to function when it would otherwise be difficult to do so. Because we may want to add other functions for performing other kinds of surgery in the future, the new contrib module is called pg_surgery rather than something specific to these functions. I proposed back-patching this so that it could be more easily used by people running existing releases who are facing these kinds of problems, but that proposal did not attract enough support, so no back-patch for now. Ashutosh Sharma, reviewed and tested by Andrey M. Borodin, M. Beena Emerson, Masahiko Sawada, Rajkumar Raghuwanshi, Asim Praveen, and Mark Dilger, and somewhat revised by me. Discussion: http://postgr.es/m/CA+TgmoZW1fsU-QUNCRUQMGUygBDPVeOTLCqRdQZch=EYZnctSA@mail.gmail.com
24 lines
479 B
Makefile
24 lines
479 B
Makefile
# contrib/pg_surgery/Makefile
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MODULE_big = pg_surgery
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OBJS = \
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$(WIN32RES) \
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heap_surgery.o
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EXTENSION = pg_surgery
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DATA = pg_surgery--1.0.sql
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PGFILEDESC = "pg_surgery - perform surgery on a damaged relation"
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REGRESS = heap_surgery
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ifdef USE_PGXS
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PG_CONFIG = pg_config
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PGXS := $(shell $(PG_CONFIG) --pgxs)
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include $(PGXS)
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else
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subdir = contrib/pg_surgery
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top_builddir = ../..
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include $(top_builddir)/src/Makefile.global
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include $(top_srcdir)/contrib/contrib-global.mk
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endif
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