diff options
Diffstat (limited to 'src/backend/storage/smgr/smgr.c')
| -rw-r--r-- | src/backend/storage/smgr/smgr.c | 115 |
1 files changed, 94 insertions, 21 deletions
diff --git a/src/backend/storage/smgr/smgr.c b/src/backend/storage/smgr/smgr.c index c7783d878f2..5c53d48f838 100644 --- a/src/backend/storage/smgr/smgr.c +++ b/src/backend/storage/smgr/smgr.c @@ -11,7 +11,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/storage/smgr/smgr.c,v 1.74 2004/06/18 06:13:37 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/storage/smgr/smgr.c,v 1.75 2004/07/01 00:51:07 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -80,9 +80,10 @@ static HTAB *SMgrRelationHash = NULL; * executed immediately, but is just entered in the list. When and if * the transaction commits, we can delete the physical file. * - * NOTE: the list is kept in TopMemoryContext to be sure it won't disappear - * unbetimes. It'd probably be OK to keep it in TopTransactionContext, - * but I'm being paranoid. + * The list is kept in CurTransactionContext. In subtransactions, each + * subtransaction has its own list in its own CurTransactionContext, but + * successful subtransactions attach their lists to their parent's list. + * Failed subtransactions can immediately execute the abort-time actions. */ typedef struct PendingRelDelete @@ -91,10 +92,11 @@ typedef struct PendingRelDelete int which; /* which storage manager? */ bool isTemp; /* is it a temporary relation? */ bool atCommit; /* T=delete at commit; F=delete at abort */ - struct PendingRelDelete *next; /* linked-list link */ } PendingRelDelete; -static PendingRelDelete *pendingDeletes = NULL; /* head of linked list */ +static List *pendingDeletes = NIL; /* head of linked list */ + +static List *upperPendingDeletes = NIL; /* list of upper-xact lists */ /* @@ -305,6 +307,7 @@ smgrcreate(SMgrRelation reln, bool isTemp, bool isRedo) XLogRecData rdata; xl_smgr_create xlrec; PendingRelDelete *pending; + MemoryContext old_cxt; if (! (*(smgrsw[reln->smgr_which].smgr_create)) (reln, isRedo)) ereport(ERROR, @@ -332,14 +335,17 @@ smgrcreate(SMgrRelation reln, bool isTemp, bool isRedo) lsn = XLogInsert(RM_SMGR_ID, XLOG_SMGR_CREATE | XLOG_NO_TRAN, &rdata); /* Add the relation to the list of stuff to delete at abort */ - pending = (PendingRelDelete *) - MemoryContextAlloc(TopMemoryContext, sizeof(PendingRelDelete)); + old_cxt = MemoryContextSwitchTo(CurTransactionContext); + + pending = (PendingRelDelete *) palloc(sizeof(PendingRelDelete)); pending->relnode = reln->smgr_rnode; pending->which = reln->smgr_which; pending->isTemp = isTemp; pending->atCommit = false; /* delete if abort */ - pending->next = pendingDeletes; - pendingDeletes = pending; + + pendingDeletes = lcons(pending, pendingDeletes); + + MemoryContextSwitchTo(old_cxt); } /* @@ -354,16 +360,20 @@ void smgrscheduleunlink(SMgrRelation reln, bool isTemp) { PendingRelDelete *pending; + MemoryContext old_cxt; /* Add the relation to the list of stuff to delete at commit */ - pending = (PendingRelDelete *) - MemoryContextAlloc(TopMemoryContext, sizeof(PendingRelDelete)); + old_cxt = MemoryContextSwitchTo(CurTransactionContext); + + pending = (PendingRelDelete *) palloc(sizeof(PendingRelDelete)); pending->relnode = reln->smgr_rnode; pending->which = reln->smgr_which; pending->isTemp = isTemp; pending->atCommit = true; /* delete if commit */ - pending->next = pendingDeletes; - pendingDeletes = pending; + + pendingDeletes = lcons(pending, pendingDeletes); + + MemoryContextSwitchTo(old_cxt); /* * NOTE: if the relation was created in this transaction, it will now @@ -627,18 +637,21 @@ smgrimmedsync(SMgrRelation reln) void smgrDoPendingDeletes(bool isCommit) { - while (pendingDeletes != NULL) + ListCell *p; + + foreach(p, pendingDeletes) { - PendingRelDelete *pending = pendingDeletes; + PendingRelDelete *pending = lfirst(p); - pendingDeletes = pending->next; if (pending->atCommit == isCommit) smgr_internal_unlink(pending->relnode, pending->which, pending->isTemp, false); - pfree(pending); } + + /* We needn't free the cells since they are in CurTransactionContext */ + pendingDeletes = NIL; } /* @@ -647,17 +660,22 @@ smgrDoPendingDeletes(bool isCommit) * The return value is the number of relations scheduled for termination. * *ptr is set to point to a freshly-palloc'd array of RelFileNodes. * If there are no relations to be deleted, *ptr is set to NULL. + * + * Note that the list does not include anything scheduled for termination + * by upper-level transactions. */ int smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr) { int nrels; RelFileNode *rptr; - PendingRelDelete *pending; + ListCell *p; nrels = 0; - for (pending = pendingDeletes; pending != NULL; pending = pending->next) + foreach(p, pendingDeletes) { + PendingRelDelete *pending = lfirst(p); + if (pending->atCommit == forCommit) nrels++; } @@ -668,8 +686,10 @@ smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr) } rptr = (RelFileNode *) palloc(nrels * sizeof(RelFileNode)); *ptr = rptr; - for (pending = pendingDeletes; pending != NULL; pending = pending->next) + foreach(p, pendingDeletes) { + PendingRelDelete *pending = lfirst(p); + if (pending->atCommit == forCommit) *rptr++ = pending->relnode; } @@ -677,6 +697,59 @@ smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr) } /* + * AtSubStart_smgr() --- Take care of subtransaction start. + * + * Push empty state for the new subtransaction. + */ +void +AtSubStart_smgr(void) +{ + MemoryContext old_cxt; + + /* Keep the list-of-lists in TopTransactionContext for simplicity */ + old_cxt = MemoryContextSwitchTo(TopTransactionContext); + + upperPendingDeletes = lcons(pendingDeletes, upperPendingDeletes); + + pendingDeletes = NIL; + + MemoryContextSwitchTo(old_cxt); +} + +/* + * AtSubCommit_smgr() --- Take care of subtransaction commit. + * + * Reassign all items in the pending deletes list to the parent transaction. + */ +void +AtSubCommit_smgr(void) +{ + List *parentPendingDeletes; + + parentPendingDeletes = (List *) linitial(upperPendingDeletes); + upperPendingDeletes = list_delete_first(upperPendingDeletes); + + pendingDeletes = list_concat(parentPendingDeletes, pendingDeletes); +} + +/* + * AtSubAbort_smgr() --- Take care of subtransaction abort. + * + * Delete created relations and forget about deleted relations. + * We can execute these operations immediately because we know this + * subtransaction will not commit. + */ +void +AtSubAbort_smgr(void) +{ + smgrDoPendingDeletes(false); + + /* Must pop the stack, too */ + pendingDeletes = (List *) linitial(upperPendingDeletes); + upperPendingDeletes = list_delete_first(upperPendingDeletes); +} + +/* * smgrcommit() -- Prepare to commit changes made during the current * transaction. * |