FaFailed to execute phase [query], all shards failed; es查询有点频繁，为什么老是会抛出这个信息

每次查询范围的量有点多，就使用了scroll去查。然后查看日志发现有（ Failed to execute phase [query], all shards failed; ）分片失败这样的情况出现。
bulk插入的数据也是异常失败，查看es的日志发现GC很高导致数据节点宕机
（[gc][old][76468][5363] duration [17.6s], collections [1]/[18.3s], total [17.6s]/[10.8m], memory [30.8gb]->[30.6gb]/[31.8gb], all_pools {[young] [867.8mb]->[82.5mb]/[1.1gb]}{[survivor] [149.7mb]->[0b]/[149.7mb]}{[old] [29.8gb]->[30.5gb]/[30.5gb]}
）
（[old][76472][5366] duration [8.8s], collections [1]/[9.1s], total [8.8s]/[11.4m], memory [31.6gb]->[31.7gb]/[31.8gb], all_pools {[young] [1.1gb]->[1.1gb]/[1.1gb]}{[survivor] [0b]->[91.3m[gc][old][76468][5363] duration [17.6s], collections [1]/[18.3s], total [17.6s]/[10.8m], memory [30.8gb]->[30.6gb]/[31.8gb], all_pools {[young] [867.8mb]->[82.5mb]/[1.1gb]}{[survivor] [149.7mb]->[0b]/[149.7mb]}{[old] [29.8gb]->[30.5gb]/[30.5gb]}
b]/[149.7mb]}{[old] [30.5gb]->[30.5gb]/[30.5gb]}
）（ [gc][76475] overhead, spent [16.8s] collecting in the last [16.9s]
[2018-10-16T13:02:46,728][ERROR][o.e.b.ElasticsearchUncaughtExceptionHandler] [pbossops-es2] fatal error in thread [elasticsearch[pbossops-es2][search][T#18]], exiting
java.lang.OutOfMemoryError: Java heap space）

想请教是什么样的情况下会出现这样的问题，集群的配置是否不合理