Engine Atlas

MySQL 8.4.10Captured

See how SQL becomes a real data flow

Replay a MySQL 8.4.10 execution plan and the row sets from a deterministic fixture in one synchronized view.

Open workbench
Order Search Execution Workbench showing SQL, Execution Plan, Data Lens, and Evidence together
Featured Lab Order Search Execution

Compare how the same SQL produces a full scan and a composite-index access path, grounded in actual rows.

Interactive labs

Compare six execution topics directly

Trace query flow, composite indexes, cardinality estimates, join algorithms, internal temporary work, and secondary-index storage against SQL, plans, and real rows.

  1. LAB 01

    Order Search Execution

    Compare the table, index, filter, join, sort, and result flow produced by the same order query with a full scan and a composite index.

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  2. LAB 02

    Composite Index Anatomy

    Switch among three index orders and follow the equality prefix, first range, ICP, base-row lookup, and index-only projection through real plans and rows.

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  3. LAB 03

    Cardinality & Histograms

    Compare how absent, fresh, and stale histograms change filtered and estimated Filter rows over identical data, grounded in captured buckets, plans, and 128 actual rows.

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  4. LAB 04

    Nested Loop vs Hash Join

    Compare Hash Join build/probe flow with Indexed Nested Loop outer/inner lookups over identical SQL and fixture data, grounded in native plans, actual rows and loops, and exact matched pairs.

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  5. LAB 05

    Internal Temporary Work

    Trace the internal temporary rows, filesort, and LIMIT boundary produced by one GROUP BY query across RAM, mmap overflow, and InnoDB on-disk profiles, grounded in exact rows and captured memory.

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  6. LAB 06

    Secondary Index & Buffer Pool

    Trace one non-covering range query from a secondary entry and carried primary key to its clustered row, then compare captured cold and warm Buffer Pool pages and counters.

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Workbench

Four synchronized surfaces

  1. SQL

    The active clause and predicate

  2. Execution Plan

    The active operator, access type, selected key, rows, and cost

  3. Data Lens

    Table scans, index candidates, filters, joins, sorting, and result rows

  4. Plan & Evidence

    The raw plan line and source behind each metric

Evidence methodology

Evidence stays separate from explanation

Every visible value is labeled by where it comes from.

Captured
EXPLAIN, Performance Schema, Handler counters, and results from MySQL 8.4.10
Derived · fixture
Exact row sets calculated by applying the same predicate to the fixed fixture
Logical model
A B-tree teaching model built from the index definition and candidate keys