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Commit22fe3d4

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committed
I finally understood what sinvaladt.c is doing --- and it
offended my aesthestic sensibility that there was so much unreadable codedoing so little. Rewritten code is about half the size, faster, and(I hope) much more intelligible.
1 parentcc8b67a commit22fe3d4

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4 files changed

+316
-820
lines changed

4 files changed

+316
-820
lines changed

‎src/backend/storage/ipc/sinval.c‎

Lines changed: 15 additions & 44 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinval.c,v 1.17 1999/09/04 18:36:45 tgl Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/storage/ipc/sinval.c,v 1.18 1999/09/06 19:37:38 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -21,12 +21,6 @@
2121
#include"storage/sinval.h"
2222
#include"storage/sinvaladt.h"
2323

24-
externSISeg*shmInvalBuffer;/* the shared buffer segment, set by
25-
* SISegmentAttach()
26-
*/
27-
externBackendIdMyBackendId;
28-
externBackendTagMyBackendTag;
29-
3024
SPINLOCKSInvalLock= (SPINLOCK)NULL;
3125

3226
/****************************************************************************/
@@ -39,11 +33,6 @@ CreateSharedInvalidationState(IPCKey key, int maxBackends)
3933
{
4034
intstatus;
4135

42-
/*
43-
* REMOVED SISyncKill(IPCKeyGetSIBufferMemorySemaphoreKey(key));
44-
* SISyncInit(IPCKeyGetSIBufferMemorySemaphoreKey(key));
45-
*/
46-
4736
/* SInvalLock gets set in spin.c, during spinlock init */
4837
status=SISegmentInit(true,IPCKeyGetSIBufferMemoryBlock(key),
4938
maxBackends);
@@ -53,9 +42,9 @@ CreateSharedInvalidationState(IPCKey key, int maxBackends)
5342
}
5443

5544
/****************************************************************************/
56-
/*AttachSharedInvalidationState(key) Attachabuffer segment*/
45+
/*AttachSharedInvalidationState(key) Attachto existingbuffer segment*/
5746
/**/
58-
/*should be calledonlybythe POSTMASTER*/
47+
/*should be called byeach backend during startup*/
5948
/****************************************************************************/
6049
void
6150
AttachSharedInvalidationState(IPCKeykey)
@@ -74,6 +63,11 @@ AttachSharedInvalidationState(IPCKey key)
7463
elog(FATAL,"AttachSharedInvalidationState: failed segment init");
7564
}
7665

66+
/*
67+
* InitSharedInvalidationState
68+
*Initialize new backend's state info in buffer segment.
69+
*Must be called after AttachSharedInvalidationState().
70+
*/
7771
void
7872
InitSharedInvalidationState(void)
7973
{
@@ -88,24 +82,19 @@ InitSharedInvalidationState(void)
8882

8983
/*
9084
* RegisterSharedInvalid
91-
*Returns anew localcacheinvalidationstate containing a new entry.
85+
*Add ashared-cache-invalidationmessage to the global SI message queue.
9286
*
9387
* Note:
9488
*Assumes hash index is valid.
9589
*Assumes item pointer is valid.
9690
*/
97-
/****************************************************************************/
98-
/*RegisterSharedInvalid(cacheId, hashIndex, pointer)*/
99-
/**/
100-
/*register a message in the buffer*/
101-
/*should be called by a backend*/
102-
/****************************************************************************/
10391
void
10492
RegisterSharedInvalid(intcacheId,/* XXX */
10593
IndexhashIndex,
10694
ItemPointerpointer)
10795
{
108-
SharedInvalidDatanewInvalid;
96+
SharedInvalidDatanewInvalid;
97+
boolinsertOK;
10998

11099
/*
111100
* This code has been hacked to accept two types of messages. This
@@ -127,34 +116,16 @@ RegisterSharedInvalid(int cacheId,/* XXX */
127116
ItemPointerSetInvalid(&newInvalid.pointerData);
128117

129118
SpinAcquire(SInvalLock);
130-
while (!SISetDataEntry(shmInvalBuffer,&newInvalid))
131-
{
132-
/* buffer full */
133-
/* release a message, mark process cache states to be invalid */
134-
SISetProcStateInvalid(shmInvalBuffer);
135-
136-
if (!SIDelDataEntries(shmInvalBuffer,1))
137-
{
138-
/* inconsistent buffer state -- shd never happen */
139-
SpinRelease(SInvalLock);
140-
elog(FATAL,"RegisterSharedInvalid: inconsistent buffer state");
141-
}
142-
143-
/* loop around to try write again */
144-
}
119+
insertOK=SIInsertDataEntry(shmInvalBuffer,&newInvalid);
145120
SpinRelease(SInvalLock);
121+
if (!insertOK)
122+
elog(NOTICE,"RegisterSharedInvalid: SI buffer overflow");
146123
}
147124

148125
/*
149126
* InvalidateSharedInvalid
150-
*Processes all entries in a shared cache invalidation state.
127+
*Process shared-cache-invalidation messages waiting for this backend
151128
*/
152-
/****************************************************************************/
153-
/*InvalidateSharedInvalid(invalFunction, resetFunction)*/
154-
/**/
155-
/*invalidate a message in the buffer (read and clean up)*/
156-
/*should be called by a backend*/
157-
/****************************************************************************/
158129
void
159130
InvalidateSharedInvalid(void (*invalFunction) (),
160131
void (*resetFunction) ())

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