Function ProcessBatchDeletion

pg_documentdb/src/commands/delete.c:604–685

* ProcessBatchDeletion iterates over the deletes array and executes each * deletion in a subtransaction, to allow us to continue after an error. * * If batchSpec->isOrdered is false, we continue with remaining tasks an * error. * * We Use subtransactions which effectively * does each delete operation in a separate transaction. */

 * does each delete operation in a separate transaction.
 */
static void
ProcessBatchDeletion(MongoCollection *collection, BatchDeletionSpec *batchSpec,
					 bool forceInline, text *transactionId,
					 BatchDeletionResult *batchResult)
{
	PostProcessDeleteBatchSpec(batchSpec);
	List *deletions = batchSpec->deletionsProcessed;
	bool isOrdered = batchSpec->isOrdered;

	/*
	 * Execute the query inside a sub-transaction, so we can restore order
	 * after a failure.
	 */
	MemoryContext oldContext = CurrentMemoryContext;
	ResourceOwner oldOwner = CurrentResourceOwner;

	batchResult->ok = 1;
	batchResult->rowsDeleted = 0;
	batchResult->writeErrors = NIL;

	/* declared volatile because of the longjmp in PG_CATCH */
	volatile int deleteIndex = 0;

	ListCell *deletionCell = NULL;
	foreach(deletionCell, deletions)
	{
		CHECK_FOR_INTERRUPTS();

		DeletionSpec *deletionSpec = lfirst(deletionCell);

		/* declared volatile because of the longjmp in PG_CATCH */
		volatile uint64 rowsDeleted = 0;
		volatile bool isSuccess = false;

		/* use a subtransaction to correctly handle failures */
		BeginInternalSubTransaction(NULL);

		PG_TRY();
		{
			rowsDeleted = ProcessDeletion(collection, deletionSpec, forceInline,
										  transactionId);

			/* Commit the inner transaction, return to outer xact context */
			ReleaseCurrentSubTransaction();
			MemoryContextSwitchTo(oldContext);
			CurrentResourceOwner = oldOwner;

			isSuccess = true;
		}
		PG_CATCH();
		{
			MemoryContextSwitchTo(oldContext);
			ErrorData *errorData = CopyErrorDataAndFlush();

			/* Abort inner transaction */
			RollbackAndReleaseCurrentSubTransaction();
			MemoryContextSwitchTo(oldContext);
			CurrentResourceOwner = oldOwner;