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Profile API
editProfile API
editThis functionality is in technical preview and may be changed or removed in a future release. Elastic will work to fix any issues, but features in technical preview are not subject to the support SLA of official GA features.
The Profile API provides detailed timing information about the execution of individual components in a search request. It gives the user insight into how search requests are executed at a low level so that the user can understand why certain requests are slow, and take steps to improve them.
The output from the Profile API is very verbose, especially for complicated requests executed across many shards. Pretty-printing the response is recommended to help understand the output
Usage
editAny _search
request can be profiled by adding a top-level profile
parameter:
This will yield the following result:
{ "took": 25, "timed_out": false, "_shards": { "total": 1, "successful": 1, "failed": 0 }, "hits": { "total": 4, "max_score": 0.5093388, "hits": [...] }, "profile": { "shards": [ { "id": "[2aE02wS1R8q_QFnYu6vDVQ][twitter][1]", "searches": [ { "query": [ { "type": "BooleanQuery", "description": "message:message message:number", "time": "1.873811000ms", "breakdown": { "score": 51306, "score_count": 4, "build_scorer": 2935582, "build_scorer_count": 1, "match": 0, "match_count": 0, "create_weight": 919297, "create_weight_count": 1, "next_doc": 53876, "next_doc_count": 5, "advance": 0, "advance_count": 0 }, "children": [ { "type": "TermQuery", "description": "message:message", "time": "0.3919430000ms", "breakdown": { "score": 28776, "score_count": 4, "build_scorer": 784451, "build_scorer_count": 1, "match": 0, "match_count": 0, "create_weight": 1669564, "create_weight_count": 1, "next_doc": 10111, "next_doc_count": 5, "advance": 0, "advance_count": 0 } }, { "type": "TermQuery", "description": "message:number", "time": "0.2106820000ms", "breakdown": { "score": 4552, "score_count": 4, "build_scorer": 42602, "build_scorer_count": 1, "match": 0, "match_count": 0, "create_weight": 89323, "create_weight_count": 1, "next_doc": 2852, "next_doc_count": 5, "advance": 0, "advance_count": 0 } } ] } ], "rewrite_time": 51443, "collector": [ { "name": "CancellableCollector", "reason": "search_cancelled", "time": "0.3043110000ms", "children": [ { "name": "SimpleTopScoreDocCollector", "reason": "search_top_hits", "time": "0.03227300000ms" } ] } ] } ], "aggregations": [] } ] } }
Even for a simple query, the response is relatively complicated. Let’s break it down piece-by-piece before moving to more complex examples.
First, the overall structure of the profile response is as follows:
{ "profile": { "shards": [ { "id": "[2aE02wS1R8q_QFnYu6vDVQ][twitter][1]", "searches": [ { "query": [...], "rewrite_time": 51443, "collector": [...] } ], "aggregations": [...] } ] } }
A profile is returned for each shard that participated in the response, and is identified by a unique ID |
|
Each profile contains a section which holds details about the query execution |
|
Each profile has a single time representing the cumulative rewrite time |
|
Each profile also contains a section about the Lucene Collectors which run the search |
|
Each profile contains a section which holds the details about the aggregation execution |
Because a search request may be executed against one or more shards in an index, and a search may cover
one or more indices, the top level element in the profile response is an array of shard
objects.
Each shard object lists it’s id
which uniquely identifies the shard. The ID’s format is
[nodeID][indexName][shardID]
.
The profile itself may consist of one or more "searches", where a search is a query executed against the underlying
Lucene index. Most Search Requests submitted by the user will only execute a single search
against the Lucene index.
But occasionally multiple searches will be executed, such as including a global aggregation (which needs to execute
a secondary "match_all" query for the global context).
Inside each search
object there will be two arrays of profiled information:
a query
array and a collector
array. Alongside the search
object is an aggregations
object that contains the profile information for the aggregations. In the future, more sections may be added, such as suggest
, highlight
, etc
There will also be a rewrite
metric showing the total time spent rewriting the query (in nanoseconds).