/*
* Report dependencies on remote databases. If we're truncating the
* output already, don't put a line per database, but a single one for all
* of them. Otherwise add as many as fit in MAX_REPORTED_DEPS.
*/
foreach(cell, remDeps)
{
remoteDep *dep = lfirst(cell);
object.classId = DatabaseRelationId;
object.objectId = dep->dbOid;
object.objectSubId = 0;
if (numReportedDeps < MAX_REPORTED_DEPS)
{
numReportedDeps++;
storeObjectDescription(&descs, REMOTE_OBJECT, &object,
SHARED_DEPENDENCY_INVALID, dep->count);
}
else
{
numNotReportedDbs++;
/* initialize the server-only log line */
if (alldescs.len == 0)
appendBinaryStringInfo(&alldescs, descs.data, descs.len);
storeObjectDescription(&alldescs, REMOTE_OBJECT, &object,
SHARED_DEPENDENCY_INVALID, dep->count);
}
}
/*
* Summarize dependencies in remote databases.
*/
foreach(cell, remDeps)
{
remoteDep *dep = lfirst(cell);
object.classId = DatabaseRelationId;
object.objectId = dep->dbOid;
object.objectSubId = 0;
if (numReportedDeps < MAX_REPORTED_DEPS)
{
numReportedDeps++;
storeObjectDescription(&descs, REMOTE_OBJECT, &object,
SHARED_DEPENDENCY_INVALID, dep->count);
}
else
numNotReportedDbs++;
storeObjectDescription(&alldescs, REMOTE_OBJECT, &object,
SHARED_DEPENDENCY_INVALID, dep->count);
}
/*
* checkSharedDependencies
*
* Check whether there are shared dependency entries for a given shared
* object; return true if so.
*
* In addition, return a string containing a newline-separated list of object
* descriptions that depend on the shared object, or NULL if none is found.
* We actually return two such strings; the "detail" result is suitable for
* returning to the client as an errdetail() string, and is limited in size.
* The "detail_log" string is potentially much longer, and should be emitted
* to the server log only.
*
* We can find three different kinds of dependencies: dependencies on objects
* of the current database; dependencies on shared objects; and dependencies
* on objects local to other databases. We can (and do) provide descriptions
* of the two former kinds of objects, but we can't do that for "remote"
* objects, so we just provide a count of them.
*
* If we find a SHARED_DEPENDENCY_PIN entry, we can error out early.
*/
bool
checkSharedDependencies(Oid classId, Oid objectId,
char **detail_msg, char **detail_log_msg)
{
Relation sdepRel;
ScanKeyData key[2];
SysScanDesc scan;
HeapTuple tup;
int numReportedDeps = 0;
int numNotReportedDeps = 0;
int numNotReportedDbs = 0;
List *remDeps = NIL;
ListCell *cell;
ObjectAddress object;
StringInfoData descs;
StringInfoData alldescs;
/*
* We limit the number of dependencies reported to the client to
* MAX_REPORTED_DEPS, since client software may not deal well with
* enormous error strings. The server log always gets a full report.
*/
#define MAX_REPORTED_DEPS 100
initStringInfo(&descs);
initStringInfo(&alldescs);
sdepRel = heap_open(SharedDependRelationId, AccessShareLock);
ScanKeyInit(&key[0],
Anum_pg_shdepend_refclassid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(classId));
ScanKeyInit(&key[1],
Anum_pg_shdepend_refobjid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(objectId));
scan = systable_beginscan(sdepRel, SharedDependReferenceIndexId, true,
NULL, 2, key);
while (HeapTupleIsValid(tup = systable_getnext(scan)))
{
Form_pg_shdepend sdepForm = (Form_pg_shdepend) GETSTRUCT(tup);
/* This case can be dispatched quickly */
if (sdepForm->deptype == SHARED_DEPENDENCY_PIN)
{
object.classId = classId;
object.objectId = objectId;
object.objectSubId = 0;
ereport(ERROR,
(errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
errmsg("cannot drop %s because it is required by the database system",
getObjectDescription(&object))));
}
object.classId = sdepForm->classid;
object.objectId = sdepForm->objid;
object.objectSubId = sdepForm->objsubid;
/*
* If it's a dependency local to this database or it's a shared
* object, describe it.
*
* If it's a remote dependency, keep track of it so we can report the
* number of them later.
*/
if (sdepForm->dbid == MyDatabaseId)
{
if (numReportedDeps < MAX_REPORTED_DEPS)
{
numReportedDeps++;
storeObjectDescription(&descs, LOCAL_OBJECT, &object,
sdepForm->deptype, 0);
}
else
numNotReportedDeps++;
storeObjectDescription(&alldescs, LOCAL_OBJECT, &object,
sdepForm->deptype, 0);
}
else if (sdepForm->dbid == InvalidOid)
{
if (numReportedDeps < MAX_REPORTED_DEPS)
{
numReportedDeps++;
storeObjectDescription(&descs, SHARED_OBJECT, &object,
sdepForm->deptype, 0);
}
else
numNotReportedDeps++;
storeObjectDescription(&alldescs, SHARED_OBJECT, &object,
sdepForm->deptype, 0);
}
else
{
/* It's not local nor shared, so it must be remote. */
remoteDep *dep;
bool stored = false;
/*
* XXX this info is kept on a simple List. Maybe it's not good
* for performance, but using a hash table seems needlessly
* complex. The expected number of databases is not high anyway,
* I suppose.
*/
foreach(cell, remDeps)
{
dep = lfirst(cell);
if (dep->dbOid == sdepForm->dbid)
{
dep->count++;
stored = true;
break;
}
}
if (!stored)
{
dep = (remoteDep *) palloc(sizeof(remoteDep));
dep->dbOid = sdepForm->dbid;
dep->count = 1;
remDeps = lappend(remDeps, dep);
}
}
}
