[performance] retry db queries on busy errors (#2025)

* catch SQLITE_BUSY errors, wrap bun.DB to use our own busy retrier, remove unnecessary db.Error type

Signed-off-by: kim <grufwub@gmail.com>

* remove dead code

Signed-off-by: kim <grufwub@gmail.com>

* remove more dead code, add missing error arguments

Signed-off-by: kim <grufwub@gmail.com>

* update sqlite to use maxOpenConns()

Signed-off-by: kim <grufwub@gmail.com>

* add uncommitted changes

Signed-off-by: kim <grufwub@gmail.com>

* use direct calls-through for the ConnIface to make sure we don't double query hook

Signed-off-by: kim <grufwub@gmail.com>

* expose underlying bun.DB better

Signed-off-by: kim <grufwub@gmail.com>

* retry on the correct busy error

Signed-off-by: kim <grufwub@gmail.com>

* use longer possible maxRetries for db retry-backoff

Signed-off-by: kim <grufwub@gmail.com>

* remove the note regarding max-open-conns only applying to postgres

Signed-off-by: kim <grufwub@gmail.com>

* improved code commenting

Signed-off-by: kim <grufwub@gmail.com>

* remove unnecessary infof call (just use info)

Signed-off-by: kim <grufwub@gmail.com>

* rename DBConn to WrappedDB to better follow sql package name conventions

Signed-off-by: kim <grufwub@gmail.com>

* update test error string checks

Signed-off-by: kim <grufwub@gmail.com>

* shush linter

Signed-off-by: kim <grufwub@gmail.com>

* update backoff logic to be more transparent

Signed-off-by: kim <grufwub@gmail.com>

---------

Signed-off-by: kim <grufwub@gmail.com>

1 files changed, 10 insertions, 10 deletions

diff --git a/internal/db/bundb/search.go b/internal/db/bundb/search.go
index 1d7eefd48..f4e41d0f4 100644
--- a/internal/db/bundb/search.go
+++ b/internal/db/bundb/search.go
@@ -56,7 +56,7 @@ import (
 // This isn't ideal, of course, but at least we could cover the most common use case of
 // a caller paging down through results.
 type searchDB struct {
-	conn  *DBConn
+	db    *WrappedDB
 	state *state.State
 }
 
@@ -89,7 +89,7 @@ func (s *searchDB) SearchForAccounts(
 		frontToBack = true
 	)
 
-	q := s.conn.
+	q := s.db.
 		NewSelect().
 		TableExpr("? AS ?", bun.Ident("accounts"), bun.Ident("account")).
 		// Select only IDs from table.
@@ -148,7 +148,7 @@ func (s *searchDB) SearchForAccounts(
 	}
 
 	if err := q.Scan(ctx, &accountIDs); err != nil {
-		return nil, s.conn.ProcessError(err)
+		return nil, s.db.ProcessError(err)
 	}
 
 	if len(accountIDs) == 0 {
@@ -183,7 +183,7 @@ func (s *searchDB) SearchForAccounts(
 // followedAccounts returns a subquery that selects only IDs
 // of accounts that are followed by the given accountID.
 func (s *searchDB) followedAccounts(accountID string) *bun.SelectQuery {
-	return s.conn.
+	return s.db.
 		NewSelect().
 		TableExpr("? AS ?", bun.Ident("follows"), bun.Ident("follow")).
 		Column("follow.target_account_id").
@@ -196,7 +196,7 @@ func (s *searchDB) followedAccounts(accountID string) *bun.SelectQuery {
 // in the concatenation.
 func (s *searchDB) accountText(following bool) *bun.SelectQuery {
 	var (
-		accountText = s.conn.NewSelect()
+		accountText = s.db.NewSelect()
 		query       string
 		args        []interface{}
 	)
@@ -225,7 +225,7 @@ func (s *searchDB) accountText(following bool) *bun.SelectQuery {
 	// different number of placeholders depending on
 	// following/not following. COALESCE calls ensure
 	// that we're not trying to concatenate null values.
-	d := s.conn.Dialect().Name()
+	d := s.db.Dialect().Name()
 	switch {
 
 	case d == dialect.SQLite && following:
@@ -276,7 +276,7 @@ func (s *searchDB) SearchForStatuses(
 		frontToBack = true
 	)
 
-	q := s.conn.
+	q := s.db.
 		NewSelect().
 		TableExpr("? AS ?", bun.Ident("statuses"), bun.Ident("status")).
 		// Select only IDs from table
@@ -326,7 +326,7 @@ func (s *searchDB) SearchForStatuses(
 	}
 
 	if err := q.Scan(ctx, &statusIDs); err != nil {
-		return nil, s.conn.ProcessError(err)
+		return nil, s.db.ProcessError(err)
 	}
 
 	if len(statusIDs) == 0 {
@@ -361,11 +361,11 @@ func (s *searchDB) SearchForStatuses(
 // statusText returns a subquery that selects a concatenation
 // of status content and content warning as "status_text".
 func (s *searchDB) statusText() *bun.SelectQuery {
-	statusText := s.conn.NewSelect()
+	statusText := s.db.NewSelect()
 
 	// SQLite and Postgres use different
 	// syntaxes for concatenation.
-	switch s.conn.Dialect().Name() {
+	switch s.db.Dialect().Name() {
 
 	case dialect.SQLite:
 		statusText = statusText.ColumnExpr(