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Use an index to get FDWs that depend on extensions 

When the database contains many objects this function would show up in
profiles because it was doing a sequence scan on pg_depend. And with
many objects pg_depend can get very large.

This starts using an index scan to only look for rows containing FDWs,
of which there are expected to be very few (often even zero).
pull/7574/head
Jelte Fennema-Nio 2024-04-09 15:20:18 +02:00
parent 3929a5b2a6
commit 9fcb50bb7d
1 changed files with 6 additions and 13 deletions
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19
src/backend/distributed/commands/extension.c
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@ -1093,33 +1093,26 @@ List *
GetDependentFDWsToExtension(Oid extensionId)
{
List *extensionFDWs = NIL;
ScanKeyData key[3];
int scanKeyCount = 3;
ScanKeyData key[1];
HeapTuple tup;
Relation pgDepend = table_open(DependRelationId, AccessShareLock);
ScanKeyInit(&key[0],
Anum_pg_depend_refclassid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(ExtensionRelationId));
ScanKeyInit(&key[1],
Anum_pg_depend_refobjid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(extensionId));
ScanKeyInit(&key[2],
Anum_pg_depend_classid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(ForeignDataWrapperRelationId));
SysScanDesc scan = systable_beginscan(pgDepend, InvalidOid, false,
NULL, scanKeyCount, key);
SysScanDesc scan = systable_beginscan(pgDepend, DependDependerIndexId, true,
NULL, lengthof(key), key);
while (HeapTupleIsValid(tup = systable_getnext(scan)))
{
Form_pg_depend pgDependEntry = (Form_pg_depend) GETSTRUCT(tup);
if (pgDependEntry->deptype == DEPENDENCY_EXTENSION)
if (pgDependEntry->deptype == DEPENDENCY_EXTENSION &&
pgDependEntry->refclassid == ExtensionRelationId &&
pgDependEntry->refobjid == extensionId)
{
extensionFDWs = lappend_oid(extensionFDWs, pgDependEntry->objid);
}