Previous short-circuit (return 0 unconditionally) was a workaround
for two bugs that are both fixed now:
1. gengo PushLocal(0) panic on unresolved identifiers
→ fixed by 08ad6f4 (PushMemvar fallback).
2. dbInfo(DBI_FULLPATH / DBI_SHARED) returning NIL
→ fixed by d74014a (real implementations).
Restoring the original scan: walk workareas 1..250, check if any
holds an exclusive lock on the target DBF. With dbInfo now functional
and the DBI_* constants defined in include/dbinfo.ch (commit 3a00aa5),
this gives FiveSql2 real pre-flight conflict detection for concurrent
table access rather than silently proceeding into a lock failure.
Validation:
- FiveSql2 43/43
- standalone PRG with dbUseArea + five_SQL works (was the original
repro that triggered the workaround)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Implements hybrid execution model: keep AST tree-walk for SQL:2013+
features (Window, Recursive CTE, JOIN, aggregates) while compiling
simple SELECT hot paths to Go + pcode. See docs/FiveSql2-Hybrid-Plan.md
for the full architecture rationale (why not SQLite-style VDBE).
Hot path (single table, no joins/groups/aggregates):
- TryBuildFieldPositions: resolves SELECT column list to FieldPos
array once per query (bails to PRG loop on any complex expr).
- TryCompileWhere + SqlExprToPrg: walks WHERE AST, emits equivalent
PRG source, runs it through PcCompile to get a PcodeFunc.
- SqlScan RTL: Go-native scan loop — GoTop/EOF/Skip/GetValue
direct, ExecPcode per row for WHERE, result array pre-alloc.
WHERE compiler scope:
- ND_LIT numeric/logical/string (string literals AllTrim'd to match
SqlCmpEq CHAR-padding semantics; rejects embedded quotes/newlines)
- ND_COL: CHAR fields auto-wrapped with AllTrim(FieldGet(n)) based
on dbStruct() lookup cached once per query in aCompileStruct
- ND_BIN: = <> != < <= > >= AND OR + - * /
- ND_UNI: NOT -
- Anything else (ND_FN, ND_CASE, ND_SUB, ND_PAR, LIKE, IN, IS NULL,
BETWEEN, dates) returns NIL → falls back to PRG tree-walk.
Bench (50k rows, ~/tmp ext4):
Before After Speedup
Numeric WHERE ~150ms 11.7ms ~13x
String WHERE 119.3ms 10.5ms 11.4x
No WHERE - 14.6ms -
Raw RDD baseline 6.8ms 6.8ms 1.0x
Remaining gap to raw RDD (~1.5x) is structural: Value boxing, result
array construction, per-row ExecPcode frame overhead. Would need a
Value-pool or SoA refactor to close further.
Side fixes bundled:
- TSqlIndex:FindExclusive short-circuited. Originally called
dbInfo(DBI_FULLPATH)/DBI_SHARED which are unresolved symbols in
Five (dbInfo is a stub, DBI_* never defined). Panic'd with
"local variable index out of range: 0" whenever a standalone PRG
had a workarea Used before calling five_SQL. 43-test masked the
bug because it only reached FindExclusive with no open workareas.
Restore the scan once dbInfo lands in hbrtl.
- cmd/five/main.go: FIVE_KEEP_BUILD=1 env var keeps the temp Go
project around for debugging gengo output.
Validation:
- FiveSql2 43/43
- Harbour compat 51/51
- go test ./... ALL PASS
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
