reduce CGO calls when scanning rows #1291
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Edit: this PR now includes #1294 since it fixes the CIFuzz and macOS tests. |
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Codecov ReportAttention: Patch coverage is
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## master #1291 +/- ##
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- Coverage 47.16% 47.14% -0.02%
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Files 12 12
Lines 1533 1542 +9
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+ Hits 723 727 +4
- Misses 669 672 +3
- Partials 141 143 +2 ☔ View full report in Codecov by Sentry. |
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Note: this PR includes #1294 since it fixes the CIFuzz and macOS tests. |
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sqlite3.go
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| // DeclType returns the declared type, which is currently GO_SQLITE3_DECL_DATE | ||
| // or GO_SQLITE3_DECL_BOOL, since those are the only two types that we need for | ||
| // converting values. | ||
| func (c columnType) DeclType() int { |
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Why are these methods public?
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No reason - fixed.
| // _sqlite3_column_decltypes stores the declared column type in the typs array. | ||
| // This function must always be called before _sqlite3_column_types since it | ||
| // overwrites the datatype. | ||
| static void _sqlite3_column_decltypes(sqlite3_stmt* stmt, uint8_t *typs, int ntyps) { |
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I find it somewhat confusing that this ends up using one integer to contain both the derived declared type and also the real column type.
How much savings would there be relative to today if instead of doing this, we just added a function like static int _sqlite3_column_derived_decltype(sqlite3_stmt* stmt,int iCol)? Then that could return values from your "enum" (0, GO_SQLITE3_DECL_BOOL, or GO_SQLITE3_DECL_DATE), and would not need any bitmasking.
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I find it somewhat confusing that this ends up using one integer to contain both the derived declared type and also the real column type.
Yeah, it's a bit tricky. I originally used two slices to store the derived declared type and real type separately, but switching to using one slice and a the bit mask since it saves an alloc.
How much savings would there be relative to today if instead of doing this, we just added a function like static int _sqlite3_column_derived_decltype(sqlite3_stmt* stmt,int iCol)? Then that could return values from your "enum" (0, GO_SQLITE3_DECL_BOOL, or GO_SQLITE3_DECL_DATE), and would not need any bitmasking.
Most of the performance improvement here comes from batching the CGO calls needed to get the column's declared and real type (basically, the performance improvement comes from reducing the number of CGO calls - see BenchmarkStmt10Cols). So going back to having to call a CGO function for each column would negate most of the performance improvements here.
This commit improves the performance of queries by at least 20% by only
collecting the information needed to convert sqlite3 values to Go values
and by batching CGO calls when scanning rows (the performance
improvement scales with the number of columns being scanned).
This commit adds a new coltype field to the SQLiteRows struct which
stores the declared column type (either data/time or boolean) and the
sqlite3 datatype. Previously, this library would fetch the string
representation of each column, which is inefficient and rarely needed
since the non-standard SQLiteRows.DeclTypes method is rarely called.
It also changes the benchmark suite to use an in-memory database since
we do not want the file system interfering with benchmark results.
goos: darwin
goarch: arm64
pkg: github.com/mattn/go-sqlite3
cpu: Apple M1 Max
│ base.10.txt │ new.10.txt │
│ sec/op │ sec/op vs base │
CustomFunctions-10 3.318µ ± 2% 3.115µ ± 2% -6.10% (p=0.000 n=10)
Suite/BenchmarkExec-10 1.236µ ± 1% 1.240µ ± 2% ~ (p=0.617 n=10)
Suite/BenchmarkQuery-10 4.004µ ± 7% 3.363µ ± 2% -16.02% (p=0.000 n=10)
Suite/BenchmarkParams-10 4.241µ ± 1% 3.758µ ± 2% -11.40% (p=0.000 n=10)
Suite/BenchmarkStmt-10 2.830µ ± 0% 2.378µ ± 2% -15.97% (p=0.000 n=10)
Suite/BenchmarkRows-10 126.3µ ± 1% 101.3µ ± 1% -19.79% (p=0.000 n=10)
Suite/BenchmarkStmtRows-10 124.9µ ± 1% 100.5µ ± 2% -19.56% (p=0.000 n=10)
Suite/BenchmarkStmt10Cols-10 10.130µ ± 0% 7.042µ ± 1% -30.48% (p=0.000 n=10)
geomean 8.655µ 7.328µ -15.33%
│ base.10.txt │ new.10.txt │
│ B/op │ B/op vs base │
CustomFunctions-10 568.0 ± 0% 576.0 ± 0% +1.41% (p=0.000 n=10)
Suite/BenchmarkExec-10 128.0 ± 0% 128.0 ± 0% ~ (p=1.000 n=10) ¹
Suite/BenchmarkQuery-10 688.0 ± 0% 648.0 ± 0% -5.81% (p=0.000 n=10)
Suite/BenchmarkParams-10 1.078Ki ± 0% 1.031Ki ± 0% -4.35% (p=0.000 n=10)
Suite/BenchmarkStmt-10 920.0 ± 0% 872.0 ± 0% -5.22% (p=0.000 n=10)
Suite/BenchmarkRows-10 9.305Ki ± 0% 9.188Ki ± 0% -1.26% (p=0.000 n=10)
Suite/BenchmarkStmtRows-10 9.289Ki ± 0% 9.164Ki ± 0% -1.35% (p=0.000 n=10)
Suite/BenchmarkStmt10Cols-10 992.0 ± 0% 696.0 ± 0% -29.84% (p=0.000 n=10)
geomean 1.181Ki 1.106Ki -6.35%
¹ all samples are equal
│ base.10.txt │ new.10.txt │
│ allocs/op │ allocs/op vs base │
CustomFunctions-10 18.00 ± 0% 18.00 ± 0% ~ (p=1.000 n=10) ¹
Suite/BenchmarkExec-10 7.000 ± 0% 7.000 ± 0% ~ (p=1.000 n=10) ¹
Suite/BenchmarkQuery-10 23.00 ± 0% 23.00 ± 0% ~ (p=1.000 n=10) ¹
Suite/BenchmarkParams-10 27.00 ± 0% 27.00 ± 0% ~ (p=1.000 n=10) ¹
Suite/BenchmarkStmt-10 25.00 ± 0% 25.00 ± 0% ~ (p=1.000 n=10) ¹
Suite/BenchmarkRows-10 525.0 ± 0% 519.0 ± 0% -1.14% (p=0.000 n=10)
Suite/BenchmarkStmtRows-10 524.0 ± 0% 518.0 ± 0% -1.15% (p=0.000 n=10)
Suite/BenchmarkStmt10Cols-10 39.00 ± 0% 19.00 ± 0% -51.28% (p=0.000 n=10)
geomean 46.26 42.17 -8.86%
¹ all samples are equal
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This commit improves the performance of queries by at least 15% by only collecting the information needed to convert sqlite3 values to Go values and by batching CGO calls when scanning rows (the performance improvement scales with the number of columns being scanned).
This commit adds a new coltype field to the SQLiteRows struct which stores the declared column type (either data/time or boolean) and the sqlite3 datatype. Previously, this library would fetch the string representation of each column, which is inefficient and rarely needed since the non-standard SQLiteRows.DeclTypes method is rarely called.
It also changes the benchmark suite to use an in-memory database since we do not want the file system interfering with benchmark results.