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27846f02c1
Locking and updating the same tuple repeatedly led to some strange
multixacts being created which had several subtransactions of the same
parent transaction holding locks of the same strength. However,
once a subxact of the current transaction holds a lock of a given
strength, it's not necessary to acquire the same lock again. This made
some coding patterns much slower than required.
The fix is twofold. First we change HeapTupleSatisfiesUpdate to return
HeapTupleBeingUpdated for the case where the current transaction is
already a single-xid locker for the given tuple; it used to return
HeapTupleMayBeUpdated for that case. The new logic is simpler, and the
change to pgrowlocks is a testament to that: previously we needed to
check for the single-xid locker separately in a very ugly way. That
test is simpler now.
As fallout from the HTSU change, some of its callers need to be amended
so that tuple-locked-by-own-transaction is taken into account in the
BeingUpdated case rather than the MayBeUpdated case. For many of them
there is no difference; but heap_delete() and heap_update now check
explicitely and do not grab tuple lock in that case.
The HTSU change also means that routine MultiXactHasRunningRemoteMembers
introduced in commit
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| .. | ||
| adminpack | ||
| auth_delay | ||
| auto_explain | ||
| btree_gin | ||
| btree_gist | ||
| chkpass | ||
| citext | ||
| cube | ||
| dblink | ||
| dict_int | ||
| dict_xsyn | ||
| earthdistance | ||
| file_fdw | ||
| fuzzystrmatch | ||
| hstore | ||
| intagg | ||
| intarray | ||
| isn | ||
| lo | ||
| ltree | ||
| oid2name | ||
| pageinspect | ||
| passwordcheck | ||
| pg_archivecleanup | ||
| pg_buffercache | ||
| pg_freespacemap | ||
| pg_prewarm | ||
| pg_standby | ||
| pg_stat_statements | ||
| pg_test_fsync | ||
| pg_test_timing | ||
| pg_trgm | ||
| pg_upgrade | ||
| pg_upgrade_support | ||
| pg_xlogdump | ||
| pgbench | ||
| pgcrypto | ||
| pgrowlocks | ||
| pgstattuple | ||
| postgres_fdw | ||
| seg | ||
| sepgsql | ||
| spi | ||
| sslinfo | ||
| start-scripts | ||
| tablefunc | ||
| tcn | ||
| test_decoding | ||
| tsearch2 | ||
| unaccent | ||
| uuid-ossp | ||
| vacuumlo | ||
| xml2 | ||
| contrib-global.mk | ||
| Makefile | ||
| README | ||
The PostgreSQL contrib tree
---------------------------
This subtree contains porting tools, analysis utilities, and plug-in
features that are not part of the core PostgreSQL system, mainly
because they address a limited audience or are too experimental to be
part of the main source tree. This does not preclude their
usefulness.
User documentation for each module appears in the main SGML
documentation.
When building from the source distribution, these modules are not
built automatically, unless you build the "world" target. You can
also build and install them all by running "make all" and "make
install" in this directory; or to build and install just one selected
module, do the same in that module's subdirectory.
Some directories supply new user-defined functions, operators, or
types. To make use of one of these modules, after you have installed
the code you need to register the new SQL objects in the database
system by executing a CREATE EXTENSION command. In a fresh database,
you can simply do
CREATE EXTENSION module_name;
See the PostgreSQL documentation for more information about this
procedure.