Golang DB.Run方法代碼示例

// pushTxn attempts to abort the txn via push. The wait group is signaled on
// completion.
func pushTxn(
	ctx context.Context,
	db *client.DB,
	now hlc.Timestamp,
	txn *roachpb.Transaction,
	typ roachpb.PushTxnType,
) {
	// Attempt to push the transaction which created the intent.
	pushArgs := &roachpb.PushTxnRequest{
		Span: roachpb.Span{
			Key: txn.Key,
		},
		Now:       now,
		PusherTxn: roachpb.Transaction{TxnMeta: enginepb.TxnMeta{Priority: math.MaxInt32}},
		PusheeTxn: txn.TxnMeta,
		PushType:  typ,
	}
	b := &client.Batch{}
	b.AddRawRequest(pushArgs)
	if err := db.Run(ctx, b); err != nil {
		log.Warningf(ctx, "push of txn %s failed: %s", txn, err)
		return
	}
	br := b.RawResponse()
	// Update the supplied txn on successful push.
	*txn = br.Responses[0].GetInner().(*roachpb.PushTxnResponse).PusheeTxn
}

// pruneTimeSeries will prune data for the supplied set of time series. Time
// series series are identified by name and resolution.
//
// For each time series supplied, the pruning operation will delete all data
// older than a constant threshold. The threshold is different depending on the
// resolution; typically, lower-resolution time series data will be retained for
// a longer period.
//
// If data is stored at a resolution which is not known to the system, it is
// assumed that the resolution has been deprecated and all data for that time
// series at that resolution will be deleted.
//
// As range deletion of inline data is an idempotent operation, it is safe to
// run this operation concurrently on multiple nodes at the same time.
func pruneTimeSeries(
	ctx context.Context, db *client.DB, timeSeriesList []timeSeriesResolutionInfo, now hlc.Timestamp,
) error {
	thresholds := computeThresholds(now.WallTime)

	for _, timeSeries := range timeSeriesList {
		// Time series data for a specific resolution falls in a contiguous key
		// range, and can be deleted with a DelRange command.

		// The start key is the prefix unique to this name/resolution pair.
		start := makeDataKeySeriesPrefix(timeSeries.Name, timeSeries.Resolution)

		// The end key can be created by generating a time series key with the
		// threshold timestamp for the resolution. If the resolution is not
		// supported, the start key's PrefixEnd is used instead (which will clear
		// the time series entirely).
		var end roachpb.Key
		threshold, ok := thresholds[timeSeries.Resolution]
		if ok {
			end = MakeDataKey(timeSeries.Name, "", timeSeries.Resolution, threshold)
		} else {
			end = start.PrefixEnd()
		}

		// TODO(mrtracy): There is no reason not to execute the individual
		// deletes in parallel, although the best way to do that is not clear.
		// See the RFC PR #9343 for details.
		b := &client.Batch{}
		b.AddRawRequest(&roachpb.DeleteRangeRequest{
			Span: roachpb.Span{
				Key:    start,
				EndKey: end,
			},
			Inline: true,
		})
		if err := db.Run(ctx, b); err != nil {
			return err
		}
	}

	return nil
}

// pruneTimeSeries will prune data for the supplied set of time series. Time
// series series are identified by name and resolution.
//
// For each time series supplied, the pruning operation will delete all data
// older than a constant threshold. The threshold is different depending on the
// resolution; typically, lower-resolution time series data will be retained for
// a longer period.
//
// If data is stored at a resolution which is not known to the system, it is
// assumed that the resolution has been deprecated and all data for that time
// series at that resolution will be deleted.
//
// As range deletion of inline data is an idempotent operation, it is safe to
// run this operation concurrently on multiple nodes at the same time.
func pruneTimeSeries(
	ctx context.Context, db *client.DB, timeSeriesList []timeSeriesResolutionInfo, now hlc.Timestamp,
) error {
	thresholds := computeThresholds(now.WallTime)

	b := &client.Batch{}
	for _, timeSeries := range timeSeriesList {
		// Time series data for a specific resolution falls in a contiguous key
		// range, and can be deleted with a DelRange command.

		// The start key is the prefix unique to this name/resolution pair.
		start := makeDataKeySeriesPrefix(timeSeries.Name, timeSeries.Resolution)

		// The end key can be created by generating a time series key with the
		// threshold timestamp for the resolution. If the resolution is not
		// supported, the start key's PrefixEnd is used instead (which will clear
		// the time series entirely).
		var end roachpb.Key
		threshold, ok := thresholds[timeSeries.Resolution]
		if ok {
			end = MakeDataKey(timeSeries.Name, "", timeSeries.Resolution, threshold)
		} else {
			end = start.PrefixEnd()
		}

		b.AddRawRequest(&roachpb.DeleteRangeRequest{
			Span: roachpb.Span{
				Key:    start,
				EndKey: end,
			},
			Inline: true,
		})
	}

	return db.Run(ctx, b)
}