CharlesKWON
5bba0c2dae
Continues the multi-session concurrency cleanup. Phase 1 moved
the visible txn + plan-cache state onto TSqlSession; this pass
takes the next batch of "shared by accident" STATICs that
surfaced as Go-level `concurrent map writes` panics under
5-worker pgserver load:
s_aOuterStack — subquery-nesting stack
s_hDmlPcodeCache — DML pcode cache (schema-version keyed)
s_lCteDiskSeen — CTE-materialised-to-DBF flag
Each is now a DATA field on TSqlSession, initialised in New().
TSqlExecutor's 25 access sites (sed-rewritten under inspection)
now route through `::oSession:fieldname`. The standalone
`SqlDmlPcodeCacheReset()` helper keeps a backward-compatible
signature: callers may pass an explicit oSession, otherwise it
falls back to SqlDefaultSession() (preserves embedded-mode
ergonomics).
Remaining STATICs in TSqlExecutor.prg (s_nSchemaVer, s_nRCJSeq,
s_hAutoInc) are cross-session-shared by design — schema-version
bumps must invalidate every peer's plan cache, RCJ alias
sequence needs cross-connection uniqueness, and IDENTITY columns
must hand out monotonically increasing values across all writers
into the same table. Those need atomic / mutex guards rather
than per-session ownership; tracked as a follow-up.
Measured impact on the pgserver stress harness (20 runs each):
3-worker 5-worker
Layer 1+2: 16/20 (80%) 10/20 (50%)
+3a: 16/20 (80%) 10/20 (50%)
+THIS: 18/20 (90%) 16/20 (80%)
The remaining flake comes from s_hAutoInc's lazy map init under
concurrent IDENTITY-table writers and a few interleavings of the
header max-merge path. Both are tractable with the planned
atomic / mutex shims and the multi-area mmap-gen registry; both
deferred to the follow-up commit to keep this diff focused on
the move-to-session pattern.
All six release gates green:
go test ./... ✓
FiveSql2 SQL:1999 43/43 ✓
Harbour compat 56/56 ✓
std.ch 17/17 ✓
FRB 7/7 ✓
pgserver integration 6/6 ✓
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.