Searching a large number of unavailable shards through e.g. the `*` pattern while a large cluster is recovering from a full restart or so, leads to extremely large responses containing an exception for each shard.


![](https://user-images.githubusercontent.com/6490959/193701098-868888bc-cdc7-4104-a32a-d9c84d74aef2.png)

This example shows a 375M on heap response for ~25k unavailable shards being returned. Over the wire, this serialises with a similar size and we'd have 700M+ peak heap usage for a search request when the valid search response in a green cluster might be much smaller than this.
It seems to me that we could mostly resolve this by not returning the stack trace in this specific case of the shard not available exception (it doesn't seem valuable for users and we made a similar fix around unavailable shards in snapshots state responses)? 
server/src/main/java/org/elasticsearch/action/search/AbstractSearchAsyncAction.java
SearchShardTarget shard,
        SearchActionListener<Result> listener
    );
    protected void fork(final Runnable runnable) {
        executor.execute(new AbstractRunnable() {
            @Override
            public void onFailure(Exception e) {}
            @Override
            protected void doRun() {
                runnable.run();
            }
            @Override
            public boolean isForceExecution() {
                
                return true;
            }
        });
    }
    @Override
    public final void executeNextPhase(SearchPhase currentPhase, SearchPhase nextPhase) {
        /* This is the main search phase transition where we move to the next phase. If all shards
         * failed or if there was a failure and partial results are not allowed, then we immediately
         * fail. Otherwise we continue to the next phase.
         */
        ShardOperationFailedException[] shardSearchFailures = buildShardFailures();
        if (shardSearchFailures.length == getNumShards()) {
            shardSearchFailures = ExceptionsHelper.groupBy(shardSearchFailures);
            Throwable cause = shardSearchFailures.length == 0
                ? null
                : ElasticsearchException.guessRootCauses(shardSearchFailures[0].getCause())[0];