[IGNITE-11203] SQL: global refactoring

• Type: Task
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: sql
• Assignee: Unassigned
• Reporter: Vladimir Ozerov
• Created: 05/Feb/19 12:19
• Updated: 15/Feb/19 10:49

Description

Over the years of SQL existence it's logic became overly complex as we never invested enough time into technical debt. Most prominent features that led to over-complication are:

1. Distributed joins
2. Subqueries in spliiter
3. MVCC
4. Query cancel feature
5. DML

As a result currently it is too difficult to add new features to the product: we have to spend a lot time figuring what if going on, and loose a lot on introduced bugs.

General idea of this initiative is to streamline query execution engine as much as possible. The most important things to consider:

1. Simplify H2 connection management: simple pooling, avoid exposing connection when possible
2. Execute MAP and LOCAL queries through the same flow
3. Avoid zig-zag code flow in DML stuff
4. Rework overly complex "query cancel" feature
5. Try to merge partition pruning and distributed join cost calculation

Issue Links

• is a parent of: IGNITE-6020 SQL: client should request first pages on query execution instead of first cursor read
• is a parent of: IGNITE-11206 SQL: Merge execution flow for local and map queries
• is a parent of: IGNITE-11207 SQL: Remove MapNodeResults class
• is a parent of: IGNITE-11208 SQL: Move reservations from QueryContext to MapQueryResult
• is a parent of: IGNITE-11211 SQL: Rework connection pool
• is a parent of: IGNITE-11212 SQL: Merge affinity collocation models for partition pruning and distributed joins
• is a parent of: IGNITE-11274 SQL: Make GridCacheSqlQuery immutable
• is a parent of: IGNITE-11325 SQL: Single place to start missing caches (H2Utils.checkAndStartNotStartedCache)
• is a parent of: IGNITE-4807 Move inner classes of GridQueryProcessor to top-level if possible
• is a parent of: IGNITE-5281 Change "space" notion to "cacheName"
• is a parent of: IGNITE-5284 Split IgniteH2Indexing into multiple classes if possible
• is a parent of: IGNITE-6632 SQL: simplify GridH2Row infrastructure
• is a parent of: IGNITE-10231 SQL: Extract partition pruning logic from splitter
• is a parent of: IGNITE-10253 SQL: Merge SqlQuery logic with SqlFieldsQuery
• is a parent of: IGNITE-10303 SQL: Move connection management logic into separate class
• is a parent of: IGNITE-10535 SQL: Extract partition mapping logic from GridReduceQueryExecutor into a separate class
• is a parent of: IGNITE-10578 SQL: Extract schema operations from IgniteH2Indexing into a separate class
• is a parent of: IGNITE-10812 SQL: Split classes responsible for distributed joins
• is a parent of: IGNITE-11083 SQL: Extract query model from splitter
• is a parent of: IGNITE-11160 SQL: Simplify row hierarchy
• is a parent of: IGNITE-11169 SQL: Remove collocation model-related code from GridH2QueryContext
• is a parent of: IGNITE-11180 SQL: Give more sensible names to reducer classes
• is a parent of: IGNITE-11185 SQL: Move distributed joins code from base index to H2TreeIndex
• is a parent of: IGNITE-11200 SQL: Query contexts should not be static
• is a parent of: IGNITE-11202 SQL: Move partition reservation logic to separate class
• is a parent of: IGNITE-11209 SQL: Merge DmlStatementsProcessor into IgniteH2Indexing
• is a parent of: IGNITE-11210 SQL: Introduce common logical execution plan for all query types
• is a parent of: IGNITE-11223 SQL: Make two-step plan immutable
• is a parent of: IGNITE-11226 SQL: Remove GridQueryIndexing.prepareNativeStatement
• is a parent of: IGNITE-11227 SQL: Streamline DML execution logic
• is a parent of: IGNITE-11231 SQL: Remove scan index for merge table
• is a parent of: IGNITE-11275 SQL: Move all command processing stuff to DDL processor
• is a parent of: IGNITE-11278 SQL: Extract query parsing into separate class
• is a parent of: IGNITE-11279 SQL: Remove H2's "prepared" from DML and local query plans
• is a parent of: IGNITE-11280 SQL: Cache all queries, not only two-step
• is a parent of: IGNITE-11304 SQL: Common caching of both local and distributed query metadata
• is a parent of: IGNITE-11310 SQL: Remove special interaction between query parallelism and distributed joins
• is a parent of: IGNITE-11326 SQL: Common parsing logic
• is a parent of: IGNITE-11331 SQL: Remove unnecessary parameters binding
• is a parent of: IGNITE-4872 GridQueryIndexing.registerType should return void
• is a parent of: IGNITE-4810 Remove unused "removeIndex" methods