mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-08-27 11:37:18 +02:00
e85a01df67
pointer" in every Snapshot struct. This allows removal of the case-by-case tests in HeapTupleSatisfiesVisibility, which should make it a bit faster (I didn't try any performance tests though). More importantly, we are no longer violating portable C practices by assuming that small integers are distinct from all pointer values, and HeapTupleSatisfiesDirty no longer has a non-reentrant API involving side-effects on a global variable. There were a couple of places calling HeapTupleSatisfiesXXX routines directly rather than through the HeapTupleSatisfiesVisibility macro. Since these places had to be changed anyway, I chose to make them go through the macro for uniformity. Along the way I renamed HeapTupleSatisfiesSnapshot to HeapTupleSatisfiesMVCC to emphasize that it's only used with MVCC-type snapshots. I was sorely tempted to rename HeapTupleSatisfiesVisibility to HeapTupleSatisfiesSnapshot, but forebore for the moment to avoid confusion and reduce the likelihood that this patch breaks some of the pending patches. Might want to reconsider doing that later. |
||
|---|---|---|
| .. | ||
| ipc.c | ||
| ipci.c | ||
| Makefile | ||
| pmsignal.c | ||
| procarray.c | ||
| README | ||
| shmem.c | ||
| shmqueue.c | ||
| sinval.c | ||
| sinvaladt.c | ||
$PostgreSQL: pgsql/src/backend/storage/ipc/README,v 1.4 2003/11/29 19:51:56 pgsql Exp $ Mon Jul 18 11:09:22 PDT 1988 W.KLAS Cache invalidation synchronization routines: =========================================== The cache synchronization is done using a message queue. Every backend can register a message which then has to be read by all backends. A message read by all backends is removed from the queue automatically. If a message has been lost because the buffer was full, all backends that haven't read this message will be told that they have to reset their cache state. This is done at the time when they try to read the message queue. The message queue is implemented as a shared buffer segment. Actually, the queue is a circle to allow fast inserting, reading (invalidate data) and maintaining the buffer.