Bound AST, Logical Plan, and Relational Algebra Explained
A deep technical guide to SQL parser ASTs, bound ASTs, Logical IR, Semantic IR, logical plans, and relational algebra for parser, lineage, and governance engineers.
Category gsp
general sql parser
Why DataHub Loses Column-Level Lineage on dbt Deduplication Macros — and How to Recover It
DataHub silently drops column-level lineage on the dbt-utils deduplicate macro because of how sqlglot's column resolver handles ARRAY_AGG + struct unpack. Here's why — and an open-source post-processor that recovers the missing lineage.
BigQuery Column-Level Lineage Without Metadata: Inferring STRUCT and ARRAY Types from SQL Alone
How a BigQuery-aware SQL parser can extract column-level lineage from ARRAY<STRUCT>, SELECT AS STRUCT, and array_agg(row) patterns without any catalog metadata — and where generic parsers silently fail.
OpenMetadata + MSSQL Stored Procedures: Why Your Lineage Is Silently Empty — and How to Fix It
OpenMetadata issues #16737, #25299, and #17586 report zero lineage from MSSQL stored procedures. We analyze three failure patterns — BEGIN/END blocks, temp table chains, and square bracket identifiers — with real SQL from the community, and show how gsp-openmetadata-sidecar recovers full column-level lineage.
DataHub #15327: Why Power BI M-Language Queries Produce Zero Lineage — 4-Query Deep Analysis
Deep analysis of 4 Power BI M-language queries from DataHub issue #15327. Both patterns solved: Pattern A (M navigation chains) produces table-level lineage; Pattern B (Value.NativeQuery with embedded SQL) produces column-level lineage with 6 column mappings traced through expressions.
Why Power BI SQL Comments Break Your DataHub Lineage — and How to Fix It
Power BI encodes newlines as #(lf) in M-language SQL. When DataHub parses queries with -- comments, it silently drops all subsequent JOINs from lineage. The gsp-datahub-sidecar recovers every missing relationship.
Why Your DataHub BigQuery Lineage Silently Breaks on Procedural SQL — and How to Fix It
DataHub's BigQuery ingestion silently loses lineage on procedural SQL (DECLARE, IF/THEN, CALL). This post explains why, and shows how to recover the missing lineage using an open-source sidecar tool.
GSP vs JSQLParser vs sqlglot — SQL Parser Comparison 2026
We tested General SQL Parser, JSQLParser, and sqlglot against 14 real-world SQL patterns across 6 dialects. Here are the verified results — including where each parser shines and where it struggles with Oracle, stored procedures, and BigQuery procedural SQL.
Why Most SQL Lineage Tools Skip Stored Procedures (And What You Can Do About It)
Most SQL lineage tools silently skip stored procedures. Learn why PL/SQL, T-SQL, and PL/pgSQL procedural code breaks typical parsers, and how General SQL Parser extracts column-level lineage through stored procedures -- not just around them.
General SQL Parser Java v0.5 release
There are lots of improvements since V0.4, below are some of the most important improvements: Oracle SQL and PLSQL query parse tree structure was fully accessible. toString() of all parse tree node classes was supported, so you can get text of parse…