CharlesKWON
c4ae88e76e
CTE tables now materialise via MEMRDD (no file on disk), yet the RunSelect cleanup loop was still stat-ing __cte_<name>.dbf for every CTE in every CTE query. Profile after the FetchRow rewrite pinned HbFileExists at 20.28% of total CPU — pure waste when MEMRDD is the common path. Add s_lCteDiskSeen flag, set only when the legacy DBFNTX fallback in RunSelect actually opens a pre-existing __cte_<name>.dbf (line 1247 path — rare, only for sub-executors referencing a CTE by name on a crashed-prior-run .dbf). Cleanup runs only when the flag is set. pprof delta (full bench with cache enabled): rawsyscalln: 25.56% → 8.50% (~17 points removed) HbFileExists: 20.28% → 0% (dropped out of top) Wall-clock unchanged (ENOENT stats are kernel-cached on Darwin), but this removes the last visible avoidable syscall. What's left in the profile (kevent, madvise, pthread_cond_*) is Go runtime + scheduler overhead that application code can't touch. FiveSql2 43/43, Harbour compat 56/56. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
FiveSql2 — SQL Engine for Harbour DBF/NTX/CDX
Pratt parser + SQL:1992-2023 full standard support Supports both NTX (Clipper) and CDX (FoxPro/ADS) indexes
Architecture
five_SQL("SELECT ...")
│
├── TSqlLexer Tokenizer
├── TSqlParser2 Pratt parser (data-driven operators)
├── TSqlExecutor Query executor (Volcano model)
│ ├── TSqlAlias Central alias manager (no collisions)
│ ├── TSqlIndex NTX/CDX index optimization (auto-detect)
│ ├── TSqlAgg GROUP BY / aggregation
│ ├── TSqlSort ORDER BY / DISTINCT
│ ├── TSqlDDL CREATE/DROP/ALTER TABLE/INDEX
│ └── TSqlTxn BEGIN/COMMIT/ROLLBACK
├── TSqlExpr AST nodes + expression evaluation
└── TSqlFunc 60+ scalar functions
Build & Test
export PATH="/path/to/harbour-core/bin/linux/gcc:$PATH"
export HB_INSTALL_PREFIX="/path/to/harbour-core"
make # Build all tests
make test # Run all 157 tests
make bench # Parser benchmark
make clean # Clean
SQL Standard Coverage
| Standard | Features | Tests |
|---|---|---|
| SQL:1992 | SELECT, JOIN, GROUP BY, HAVING, Subquery, CASE, CAST | 43 |
| SQL:1999 | CTE, Recursive CTE, Window Functions, MERGE | 10 |
| SQL:2003 | SIMILAR TO, GROUPING SETS, LATERAL, Window frames | 64 |
| SQL:2008 | FETCH/OFFSET, FOR UPDATE, Extended MERGE | (incl.) |
| SQL:2016 | JSON functions, LISTAGG | (incl.) |
| SQL:2023 | ANY_VALUE, GREATEST/LEAST, BOOL_AND/OR | (incl.) |
| Challenge | LeetCode-level complex queries | 15 |
| Extreme | Production analytics stress tests | 15 |
Adding New Operators
Edit TSqlParser2.prg, method InitInfixTables():
::hInfixTT[ TK_MYOP ] := { "<=>", 40, 41, ND_BIN }
One line. No structural changes needed.
Copyright
Copyright (c) 2025-2026 Charles KWON (Charles KWON OhJun) Email: charleskwonohjun@gmail.com All rights reserved.