pingcap/tidb

collect the runtime statistics for operators in the coprocessor

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#8,433 opened on Nov 24, 2018

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help wantedsig/executiontype/enhancement

Description

Feature Request

Describe the feature you'd like:

At present, TiDB has supported the explain analyze statement to show the runtime statistics about the query execution, for example:

TiDB(root@127.0.0.1:test) > explain analyze select sum(b) from t group by a;
+----------------------+----------+------+--------------------------------------------------------------------+----------------------------------+
| id                   | count    | task | operator info                                                      | execution info                   |
+----------------------+----------+------+--------------------------------------------------------------------+----------------------------------+
| StreamAgg_9          | 8000.00  | root | group by:group_0, funcs:sum(sum_0)                                 | time:399.086µs, loops:4, rows:3  |
| └─IndexLookUp_20     | 10000.00 | root |                                                                    | time:382.873µs, loops:4, rows:3  |
|   ├─IndexScan_18     | 10000.00 | cop  | table:t, index:a, range:[NULL,+inf], keep order:true, stats:pseudo |                                  |
|   └─TableScan_19     | 10000.00 | cop  | table:t, keep order:false, stats:pseudo                            |                                  |
+----------------------+----------+------+--------------------------------------------------------------------+----------------------------------+
4 rows in set (0.00 sec)

It would be more useful if we can show the runtime statistics of the operators implemented and executed in the TiKV coprocessor.

Describe alternatives you've considered: No

Teachability, Documentation, Adoption, Migration Strategy: No

Contributor guide

Tech stack
go
Domain
databasebackend
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Go programmingDistributed systems knowledgeTiDB/TiKV architecture
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
15
Research direction
The issue requests adding runtime statistics collection for operators in the TiKV coprocessor. To implement this, one should first understand the current explain analyze implementation in TiDB (e.g., files in executor/ or planner/), and the coprocessor execution framework in TiKV (likely in src/coprocessor/). Existing discussions in the issue may provide direction. The goal is to propagate execution metrics from TiKV's operations back to TiDB for display.
collect the runtime statistics for operators in the coprocessor · pingcap/tidb#8433 | Good First Issue