#include "commands/vacuum.h"
#include "miscadmin.h"
#include "storage/freespace.h"
+#include "storage/ipc.h"
#include "storage/lmgr.h"
#include "utils/memutils.h"
stats = (IndexBulkDeleteResult *) palloc0(sizeof(IndexBulkDeleteResult));
/* Establish the vacuum cycle ID to use for this scan */
- PG_TRY();
+ /* The ENSURE stuff ensures we clean up shared memory on failure */
+ PG_ENSURE_ERROR_CLEANUP(_bt_end_vacuum_callback, PointerGetDatum(rel));
{
cycleid = _bt_start_vacuum(rel);
btvacuumscan(info, stats, callback, callback_state, cycleid);
-
- _bt_end_vacuum(rel);
- }
- PG_CATCH();
- {
- /* Make sure shared memory gets cleaned up */
- _bt_end_vacuum(rel);
- PG_RE_THROW();
}
- PG_END_TRY();
+ PG_END_ENSURE_ERROR_CLEANUP(_bt_end_vacuum_callback, PointerGetDatum(rel));
+ _bt_end_vacuum(rel);
PG_RETURN_POINTER(stats);
}
/*
* _bt_start_vacuum --- assign a cycle ID to a just-starting VACUUM operation
*
- * Note: the caller must guarantee (via PG_TRY) that it will eventually call
- * _bt_end_vacuum, else we'll permanently leak an array slot.
+ * Note: the caller must guarantee that it will eventually call
+ * _bt_end_vacuum, else we'll permanently leak an array slot. To ensure
+ * that this happens even in elog(FATAL) scenarios, the appropriate coding
+ * is not just a PG_TRY, but
+ * PG_ENSURE_ERROR_CLEANUP(_bt_end_vacuum_callback, PointerGetDatum(rel))
*/
BTCycleId
_bt_start_vacuum(Relation rel)
LWLockRelease(BtreeVacuumLock);
}
+/*
+ * _bt_end_vacuum wrapped as an on_shmem_exit callback function
+ */
+void
+_bt_end_vacuum_callback(int code, Datum arg)
+{
+ _bt_end_vacuum((Relation) DatumGetPointer(arg));
+}
+
/*
* BTreeShmemSize --- report amount of shared memory space needed
*/
#include "postmaster/bgwriter.h"
#include "storage/bufpage.h"
#include "storage/fd.h"
+#include "storage/ipc.h"
#include "storage/pmsignal.h"
#include "storage/procarray.h"
#include "storage/smgr.h"
static void WriteControlFile(void);
static void ReadControlFile(void);
static char *str_time(pg_time_t tnow);
-static void issue_xlog_fsync(void);
-
#ifdef WAL_DEBUG
static void xlog_outrec(StringInfo buf, XLogRecord *record);
#endif
+static void issue_xlog_fsync(void);
+static void pg_start_backup_callback(int code, Datum arg);
static bool read_backup_label(XLogRecPtr *checkPointLoc,
XLogRecPtr *minRecoveryLoc);
static void rm_redo_error_callback(void *arg);
XLogCtl->Insert.forcePageWrites = true;
LWLockRelease(WALInsertLock);
- /* Use a TRY block to ensure we release forcePageWrites if fail below */
- PG_TRY();
+ /* Ensure we release forcePageWrites if fail below */
+ PG_ENSURE_ERROR_CLEANUP(pg_start_backup_callback, (Datum) 0);
{
/*
* Force a CHECKPOINT. Aside from being necessary to prevent torn
errmsg("could not write file \"%s\": %m",
BACKUP_LABEL_FILE)));
}
- PG_CATCH();
- {
- /* Turn off forcePageWrites on failure */
- LWLockAcquire(WALInsertLock, LW_EXCLUSIVE);
- XLogCtl->Insert.forcePageWrites = false;
- LWLockRelease(WALInsertLock);
-
- PG_RE_THROW();
- }
- PG_END_TRY();
+ PG_END_ENSURE_ERROR_CLEANUP(pg_start_backup_callback, (Datum) 0);
/*
* We're done. As a convenience, return the starting WAL location.
PG_RETURN_TEXT_P(cstring_to_text(xlogfilename));
}
+/* Error cleanup callback for pg_start_backup */
+static void
+pg_start_backup_callback(int code, Datum arg)
+{
+ /* Turn off forcePageWrites on failure */
+ LWLockAcquire(WALInsertLock, LW_EXCLUSIVE);
+ XLogCtl->Insert.forcePageWrites = false;
+ LWLockRelease(WALInsertLock);
+}
+
/*
* pg_stop_backup: finish taking an on-line backup dump
*
#include "pgstat.h"
#include "postmaster/bgwriter.h"
#include "storage/freespace.h"
+#include "storage/ipc.h"
#include "storage/procarray.h"
#include "storage/smgr.h"
#include "utils/acl.h"
#include "utils/tqual.h"
+typedef struct
+{
+ Oid src_dboid; /* source (template) DB */
+ Oid dest_dboid; /* DB we are trying to create */
+} createdb_failure_params;
+
/* non-export function prototypes */
+static void createdb_failure_callback(int code, Datum arg);
static bool get_db_info(const char *name, LOCKMODE lockmode,
Oid *dbIdP, Oid *ownerIdP,
int *encodingP, bool *dbIsTemplateP, bool *dbAllowConnP,
int encoding = -1;
int dbconnlimit = -1;
int ctype_encoding;
+ createdb_failure_params fparms;
/* Extract options from the statement node tree */
foreach(option, stmt->options)
/*
* Once we start copying subdirectories, we need to be able to clean 'em
- * up if we fail. Establish a TRY block to make sure this happens. (This
+ * up if we fail. Use an ENSURE block to make sure this happens. (This
* is not a 100% solution, because of the possibility of failure during
* transaction commit after we leave this routine, but it should handle
* most scenarios.)
*/
- PG_TRY();
+ fparms.src_dboid = src_dboid;
+ fparms.dest_dboid = dboid;
+ PG_ENSURE_ERROR_CLEANUP(createdb_failure_callback,
+ PointerGetDatum(&fparms));
{
/*
* Iterate through all tablespaces of the template database, and copy
*/
database_file_update_needed();
}
- PG_CATCH();
- {
- /* Release lock on source database before doing recursive remove */
- UnlockSharedObject(DatabaseRelationId, src_dboid, 0,
- ShareLock);
+ PG_END_ENSURE_ERROR_CLEANUP(createdb_failure_callback,
+ PointerGetDatum(&fparms));
+}
+
+/* Error cleanup callback for createdb */
+static void
+createdb_failure_callback(int code, Datum arg)
+{
+ createdb_failure_params *fparms = (createdb_failure_params *) DatumGetPointer(arg);
- /* Throw away any successfully copied subdirectories */
- remove_dbtablespaces(dboid);
+ /*
+ * Release lock on source database before doing recursive remove.
+ * This is not essential but it seems desirable to release the lock
+ * as soon as possible.
+ */
+ UnlockSharedObject(DatabaseRelationId, fparms->src_dboid, 0, ShareLock);
- PG_RE_THROW();
- }
- PG_END_TRY();
+ /* Throw away any successfully copied subdirectories */
+ remove_dbtablespaces(fparms->dest_dboid);
}
static struct ONEXIT
{
- void (*function) (int code, Datum arg);
+ pg_on_exit_callback function;
Datum arg;
} on_proc_exit_list[MAX_ON_EXITS], on_shmem_exit_list[MAX_ON_EXITS];
}
void
- on_shmem_exit(void (*function) (int code, Datum arg), Datum arg)
+on_shmem_exit(pg_on_exit_callback function, Datum arg)
{
if (on_shmem_exit_index >= MAX_ON_EXITS)
elog(FATAL, "out of on_shmem_exit slots");
}
int
-ExceptionalCondition(char *conditionName,
- char *errorType,
- char *fileName,
+ExceptionalCondition(const char *conditionName,
+ const char *errorType,
+ const char *fileName,
int lineNumber)
{
fprintf(stderr, "TRAP: %s(\"%s\", File: \"%s\", Line: %d)\n",
static struct ONEXIT
{
- void (*function) (int code, Datum arg);
+ pg_on_exit_callback function;
Datum arg;
} on_proc_exit_list[MAX_ON_EXITS], on_shmem_exit_list[MAX_ON_EXITS];
* ----------------------------------------------------------------
*/
void
- on_proc_exit(void (*function) (int code, Datum arg), Datum arg)
+on_proc_exit(pg_on_exit_callback function, Datum arg)
{
if (on_proc_exit_index >= MAX_ON_EXITS)
ereport(FATAL,
* ----------------------------------------------------------------
*/
void
- on_shmem_exit(void (*function) (int code, Datum arg), Datum arg)
+on_shmem_exit(pg_on_exit_callback function, Datum arg)
{
if (on_shmem_exit_index >= MAX_ON_EXITS)
ereport(FATAL,
++on_shmem_exit_index;
}
+/* ----------------------------------------------------------------
+ * cancel_shmem_exit
+ *
+ * this function removes an entry, if present, from the list of
+ * functions to be invoked by shmem_exit(). For simplicity,
+ * only the latest entry can be removed. (We could work harder
+ * but there is no need for current uses.)
+ * ----------------------------------------------------------------
+ */
+void
+cancel_shmem_exit(pg_on_exit_callback function, Datum arg)
+{
+ if (on_shmem_exit_index > 0 &&
+ on_shmem_exit_list[on_shmem_exit_index - 1].function == function &&
+ on_shmem_exit_list[on_shmem_exit_index - 1].arg == arg)
+ --on_shmem_exit_index;
+}
+
/* ----------------------------------------------------------------
* on_exit_reset
*
extern BTCycleId _bt_vacuum_cycleid(Relation rel);
extern BTCycleId _bt_start_vacuum(Relation rel);
extern void _bt_end_vacuum(Relation rel);
+extern void _bt_end_vacuum_callback(int code, Datum arg);
extern Size BTreeShmemSize(void);
extern void BTreeShmemInit(void);
#ifndef IPC_H
#define IPC_H
+typedef void (*pg_on_exit_callback) (int code, Datum arg);
+
+/*----------
+ * API for handling cleanup that must occur during either ereport(ERROR)
+ * or ereport(FATAL) exits from a block of code. (Typical examples are
+ * undoing transient changes to shared-memory state.)
+ *
+ * PG_ENSURE_ERROR_CLEANUP(cleanup_function, arg);
+ * {
+ * ... code that might throw ereport(ERROR) or ereport(FATAL) ...
+ * }
+ * PG_END_ENSURE_ERROR_CLEANUP(cleanup_function, arg);
+ *
+ * where the cleanup code is in a function declared per pg_on_exit_callback.
+ * The Datum value "arg" can carry any information the cleanup function
+ * needs.
+ *
+ * This construct ensures that cleanup_function() will be called during
+ * either ERROR or FATAL exits. It will not be called on successful
+ * exit from the controlled code. (If you want it to happen then too,
+ * call the function yourself from just after the construct.)
+ *
+ * Note: the macro arguments are multiply evaluated, so avoid side-effects.
+ *----------
+ */
+#define PG_ENSURE_ERROR_CLEANUP(cleanup_function, arg) \
+ do { \
+ on_shmem_exit(cleanup_function, arg); \
+ PG_TRY()
+
+#define PG_END_ENSURE_ERROR_CLEANUP(cleanup_function, arg) \
+ cancel_shmem_exit(cleanup_function, arg); \
+ PG_CATCH(); \
+ { \
+ cancel_shmem_exit(cleanup_function, arg); \
+ cleanup_function (0, arg); \
+ PG_RE_THROW(); \
+ } \
+ PG_END_TRY(); \
+ } while (0)
+
/* ipc.c */
extern bool proc_exit_inprogress;
extern void proc_exit(int code);
extern void shmem_exit(int code);
-extern void on_proc_exit(void (*function) (int code, Datum arg), Datum arg);
-extern void on_shmem_exit(void (*function) (int code, Datum arg), Datum arg);
+extern void on_proc_exit(pg_on_exit_callback function, Datum arg);
+extern void on_shmem_exit(pg_on_exit_callback function, Datum arg);
+extern void cancel_shmem_exit(pg_on_exit_callback function, Datum arg);
extern void on_exit_reset(void);
/* ipci.c */
* of levels this will work for. It's best to keep the error recovery
* section simple enough that it can't generate any new errors, at least
* not before popping the error stack.
+ *
+ * Note: an ereport(FATAL) will not be caught by this construct; control will
+ * exit straight through proc_exit(). Therefore, do NOT put any cleanup
+ * of non-process-local resources into the error recovery section, at least
+ * not without taking thought for what will happen during ereport(FATAL).
+ * The PG_ENSURE_ERROR_CLEANUP macros provided by storage/ipc.h may be
+ * helpful in such cases.
*----------
*/
#define PG_TRY() \
projects / users / simon / postgres.git / commitdiff