Documentation
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Overview ¶
Package sqlcount counts SQL statements, so a test can assert how work GROWS rather than how long it takes.
It lives in its own package because internal/testutil imports internal/ingest, and the walker's own tests need this.
Index ¶
Constants ¶
const DriverName = "sqlite-counting"
DriverName is the driver to open a database with when the test wants its statements counted. Call Register first.
Variables ¶
This section is empty.
Functions ¶
func RegisterDriver ¶
func RegisterDriver()
RegisterDriver registers the counting driver, once per process.
The base driver is taken from an opened "sqlite" handle rather than constructed, so this stays correct if the sqlite package changes how it exports its driver.
func Reset ¶
func Reset() (count func() int64)
Reset zeroes the counter and returns a func reading it.
The counter is process-global, so a test that reads it must not run in parallel with another that issues statements.
func ResetPrepares ¶
func ResetPrepares() (count func() int64)
ResetPrepares zeroes the PREPARE counter and returns a func reading it.
A separate count from Reset because it measures a different thing. Every query EXECUTES once however it is issued, so an execution count cannot tell a reused prepared statement from one compiled afresh per call — and the compilation is the cost: a profile of a warm point read on the direct path showed SQLite's parser at ~half of all remaining time once page I/O was out of the way (mache-3063fb). A prepare count separates them: it scales with calls when a hot path hands database/sql a query STRING each time, and stays fixed when the statement is prepared once and reused.
Added per this file's own rule for counters: when a gate needs the number.
Types ¶
type ReadCounted ¶
ReadCounted is a read-only database whose file reads are counted.
func OpenReadCounted ¶
func OpenReadCounted(path string) (*ReadCounted, error)
OpenReadCounted opens the database at path read-only, counting the bytes SQLite reads from its file. The page cache is per connection, so the count for a query includes the pages it had to fetch, not ones already cached by an earlier query on the same connection.
func (*ReadCounted) Close ¶
func (r *ReadCounted) Close() error
Close closes the database, then unregisters its VFS.
func (*ReadCounted) Reset ¶
func (r *ReadCounted) Reset() (bytes func() int64)
Reset zeroes the byte counter and returns a func reading it.
Source Files