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Include the backend ID in the relpath of temporary relations.

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This allows us to reliably remove all leftover temporary relation
files on cluster startup without reference to system catalogs or WAL;
therefore, we no longer include temporary relations in XLOG_XACT_COMMIT
and XLOG_XACT_ABORT WAL records.

Since these changes require including a backend ID in each
SharedInvalSmgrMsg, the size of the SharedInvalidationMessage.id
field has been reduced from two bytes to one, and the maximum number
of connections has been reduced from INT_MAX / 4 to 2^23-1.  It would
be possible to remove these restrictions by increasing the size of
SharedInvalidationMessage by 4 bytes, but right now that doesn't seem
like a good trade-off.

Review by Jaime Casanova and Tom Lane.
This commit is contained in:
Robert Haas
2010-08-13 20:10:54 +00:00
parent 3f9479ef3f
commit debcec7dc3
37 changed files with 669 additions and 343 deletions
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20
src/backend/utils/cache/inval.c vendored
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@ -80,7 +80,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/cache/inval.c,v 1.98 2010/02/26 02:01:11 momjian Exp $
* $PostgreSQL: pgsql/src/backend/utils/cache/inval.c,v 1.99 2010/08/13 20:10:52 rhaas Exp $
*
*-------------------------------------------------------------------------
*/
@ -319,7 +319,8 @@ AddCatcacheInvalidationMessage(InvalidationListHeader *hdr,
{
SharedInvalidationMessage msg;
msg.cc.id = (int16) id;
Assert(id < CHAR_MAX);
msg.cc.id = (int8) id;
msg.cc.tuplePtr = *tuplePtr;
msg.cc.dbId = dbId;
msg.cc.hashValue = hashValue;
@ -513,7 +514,10 @@ LocalExecuteInvalidationMessage(SharedInvalidationMessage *msg)
* We could have smgr entries for relations of other databases, so no
* short-circuit test is possible here.
*/
smgrclosenode(msg->sm.rnode);
RelFileNodeBackend rnode;
rnode.node = msg->sm.rnode;
rnode.backend = (msg->sm.backend_hi << 16) | (int) msg->sm.backend_lo;
smgrclosenode(rnode);
}
else if (msg->id == SHAREDINVALRELMAP_ID)
{
@ -1163,14 +1167,20 @@ CacheInvalidateRelcacheByRelid(Oid relid)
* in commit/abort WAL entries. Instead, calls to CacheInvalidateSmgr()
* should happen in low-level smgr.c routines, which are executed while
* replaying WAL as well as when creating it.
*
* Note: In order to avoid bloating SharedInvalidationMessage, we store only
* three bytes of the backend ID using what would otherwise be padding space.
* Thus, the maximum possible backend ID is 2^23-1.
*/
void
CacheInvalidateSmgr(RelFileNode rnode)
CacheInvalidateSmgr(RelFileNodeBackend rnode)
{
SharedInvalidationMessage msg;
msg.sm.id = SHAREDINVALSMGR_ID;
msg.sm.rnode = rnode;
msg.sm.backend_hi = rnode.backend >> 16;
msg.sm.backend_lo = rnode.backend & 0xffff;
msg.sm.rnode = rnode.node;
SendSharedInvalidMessages(&msg, 1);
}