From bc3991c1851d4fbbb8881640a8fd7dddf7d7b7ca Mon Sep 17 00:00:00 2001
From: Tatsuo Ishii <ishii@postgresql.org>
Date: Sat, 20 Aug 2005 01:26:36 +0000
Subject: [PATCH] Add BackendXidGetPid().
---
src/backend/storage/ipc/procarray.c | 40 ++++++++++++++++++++++++++++-
src/include/storage/procarray.h | 3 ++-
2 files changed, 41 insertions(+), 2 deletions(-)
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index 1e2783dea80..87b1228ae6d 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -23,7 +23,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/ipc/procarray.c,v 1.4 2005/07/31 17:19:18 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/ipc/procarray.c,v 1.5 2005/08/20 01:26:36 ishii Exp $
*
*-------------------------------------------------------------------------
*/
@@ -685,6 +685,44 @@ BackendPidGetProc(int pid)
return result;
}
+/*
+ * BackendXidGetPid -- get a backend's pid given its XID
+ *
+ * Returns 0 if not found or it's a prepared transaction. Note that
+ * it is up to the caller to be sure that the question remains
+ * meaningful for long enough for the answer to be used ...
+ *
+ * Only main transaction Ids are considered. This function is mainly
+ * useful for determining what backend owns a lock.
+ */
+int
+BackendXidGetPid(TransactionId xid)
+{
+ int result = 0;
+ ProcArrayStruct *arrayP = procArray;
+ int index;
+
+ if (xid == InvalidTransactionId) /* never match invalid xid */
+ return 0;
+
+ LWLockAcquire(ProcArrayLock, LW_SHARED);
+
+ for (index = 0; index < arrayP->numProcs; index++)
+ {
+ PGPROC *proc = arrayP->procs[index];
+
+ if (proc->xid == xid)
+ {
+ result = proc->pid;
+ break;
+ }
+ }
+
+ LWLockRelease(ProcArrayLock);
+
+ return result;
+}
+
/*
* IsBackendPid -- is a given pid a running backend
*/
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index aa0adfec881..af1209d2192 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/storage/procarray.h,v 1.3 2005/07/31 17:19:22 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/storage/procarray.h,v 1.4 2005/08/20 01:26:29 ishii Exp $
*
*-------------------------------------------------------------------------
*/
@@ -27,6 +27,7 @@ extern bool TransactionIdIsActive(TransactionId xid);
extern TransactionId GetOldestXmin(bool allDbs);
extern PGPROC *BackendPidGetProc(int pid);
+extern int BackendXidGetPid(TransactionId xid);
extern bool IsBackendPid(int pid);
extern bool DatabaseHasActiveBackends(Oid databaseId, bool ignoreMyself);
--
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