Add index benchmarks against a generated 50k-row indexed table

.gitignore

@@ -45,4 +45,6 @@ project.fragment.lock.json
 artifacts/
 **/Properties/launchSettings.json
 /test/DbfDataReader.Benchmarks/BenchmarkDotNet.Artifacts/results
-**/Properties/PublishProfiles
+**/Properties/PublishProfiles
+# BenchmarkDotNet output
+BenchmarkDotNet.Artifacts/

benchmarks.md

@@ -25,3 +25,64 @@ Outliers
   DbfDataReaderBenchmarks.Sylvan: IterationTime=1.0000 s -> 3 outliers were removed (2.12 ms..2.18 ms)
   DbfDataReaderBenchmarks.NDbf: IterationTime=1.0000 s   -> 2 outliers were removed (4.37 ms, 4.44 ms)
 
+
+# v1.1.0
+
+Cross-library comparison: read every field of every record of
+`test/fixtures/tl_2019_01_place.dbf` (586 records), in the style of
+[MarkPflug/Benchmarks](https://github.com/MarkPflug/Benchmarks/blob/main/source/Benchmarks/DbfDataReaderBenchmarks.cs).
+Reproduce with:
+`dotnet run -c Release --project test/DbfDataReader.Benchmarks -p:DbfDataReaderVersion=1.1.0 -- --filter "*DbfDataReaderBenchmarks*" --job short`
+
+BenchmarkDotNet v0.15.8, macOS (Apple M3 Max), .NET 10.0.2, Job=ShortRun
+(numbers are not comparable with the v0.5.x tables above: different file and hardware)
+
+| Method  | Mean     | Error     | StdDev   | Ratio | RatioSD | Gen0    | Gen1    | Allocated | Alloc Ratio |
+|-------- |---------:|----------:|---------:|------:|--------:|--------:|--------:|----------:|------------:|
+| Sylvan  | 284.1 us |  39.52 us |  2.17 us |  0.54 |    0.02 | 41.0156 |  0.9766 | 336.81 KB |        0.80 |
+| NDbf    | 527.2 us | 429.13 us | 23.52 us |  1.00 |    0.05 | 51.7578 |  0.9766 | 423.52 KB |        1.00 |
+| DbfData | 611.1 us |  40.72 us |  2.23 us |  1.16 |    0.04 | 85.9375 | 11.7188 | 704.41 KB |        1.66 |
+
+# v2.1.0
+
+Same comparison against DbfDataReader 2.1.0 — the sequential read path is unchanged
+from 1.1.0 (all of the SQL, typed-query and index features are additive):
+
+| Method  | Mean     | Error     | StdDev   | Ratio | RatioSD | Gen0    | Gen1    | Allocated | Alloc Ratio |
+|-------- |---------:|----------:|---------:|------:|--------:|--------:|--------:|----------:|------------:|
+| Sylvan  | 286.5 us |  88.50 us |  4.85 us |  0.51 |    0.01 | 41.0156 |  0.9766 | 336.81 KB |        0.80 |
+| NDbf    | 563.2 us | 207.53 us | 11.38 us |  1.00 |    0.02 | 51.7578 |  0.9766 | 423.52 KB |        1.00 |
+| DbfData | 647.6 us | 384.16 us | 21.06 us |  1.15 |    0.04 | 85.9375 | 11.7188 | 704.41 KB |        1.66 |
+
+# v2.1.0 — automatic index use
+
+Generated 50,000-row table (65-byte records) with a compound index on `ID` (unique
+integers) and `CODE` (character keys, ~100 rows per value); see
+`BenchmarkTableGenerator` in `test/DbfDataReader.Benchmarks`. Each pair runs the same
+SQL through `DbfDbConnection` with `UseIndexes` on and off; the generated files are
+verified for index/scan equivalence before anything is measured.
+
+Reproduce with:
+`dotnet run -c Release --project test/DbfDataReader.Benchmarks -- --filter "*IndexQueryBenchmarks*"`
+
+BenchmarkDotNet v0.15.8, macOS (Apple M3 Max), .NET 10.0.2, Job=ShortRun
+
+| Method          | Categories                   | Mean         | Ratio | Allocated   | Alloc Ratio |
+|---------------- |----------------------------- |-------------:|------:|------------:|------------:|
+| 'full scan'     | character seek (100 rows)    | 22,174.38 us | 1.000 | 16813.84 KB |       1.000 |
+| index           | character seek (100 rows)    |    156.94 us | 0.007 |    81.27 KB |       0.005 |
+|                 |                              |              |       |             |             |
+| 'read all rows' | count(*) all rows            | 21,752.63 us |  1.00 | 16804.55 KB |       1.000 |
+| 'status scan'   | count(*) all rows            | 15,131.75 us |  0.70 |    10.42 KB |       0.001 |
+|                 |                              |              |       |             |             |
+| 'full scan'     | count(*) filtered (10k rows) | 23,582.86 us |  1.00 | 17980.82 KB |        1.00 |
+| 'index only'    | count(*) filtered (10k rows) |    972.50 us |  0.04 |  1201.05 KB |        0.07 |
+|                 |                              |              |       |             |             |
+| 'full scan'     | equality seek (1 row)        | 22,998.16 us | 1.000 | 17980.99 KB |       1.000 |
+| index           | equality seek (1 row)        |     50.12 us | 0.002 |    31.98 KB |       0.002 |
+|                 |                              |              |       |             |             |
+| 'full scan'     | range scan (100 rows)        | 23,776.99 us | 1.000 | 17983.64 KB |       1.000 |
+| index           | range scan (100 rows)        |    102.24 us | 0.004 |    81.12 KB |       0.005 |
+|                 |                              |              |       |             |             |
+| 'scan + sort'   | top 10 order by desc         | 60,556.31 us |  1.00 | 66357.99 KB |        1.00 |
+| index           | top 10 order by desc         |  2,986.39 us |  0.05 |  5661.96 KB |        0.09 |