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Do not skip metadata when quering SELECT * FROM ... #275

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Do not skip metadata when quering SELECT * FROM ... #275

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18 changes: 18 additions & 0 deletions session.go
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Original file line number Diff line number Diff line change
Expand Up @@ -475,6 +475,16 @@ func (s *Session) SetTrace(trace Tracer) {
s.mu.Unlock()
}

var selectWildcardNextWarning int64

func warnSelectWildcardStartPerformanceIssue() {
now := time.Now().Unix()
if atomic.LoadInt64(&selectWildcardNextWarning) < now {
atomic.StoreInt64(&selectWildcardNextWarning, now+60)
Logger.Println("warning: skipping metadata is disabled for `SELECT * FROM ...` queries due to potential correctness issues when altering the table. This may cause a decrease in performance. It is recommended to avoid using `SELECT * FROM ...` and provide specific column names.")
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}
}

// Query generates a new query object for interacting with the database.
// Further details of the query may be tweaked using the resulting query
// value before the query is executed. Query is automatically prepared
Expand All @@ -483,6 +493,10 @@ func (s *Session) Query(stmt string, values ...interface{}) *Query {
qry := queryPool.Get().(*Query)
qry.session = s
qry.stmt = stmt
if !qry.disableSkipMetadata && strings.HasPrefix(strings.ToLower(stmt), "select *") {
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qry.disableSkipMetadata = true
warnSelectWildcardStartPerformanceIssue()
}
qry.values = values
qry.defaultsFromSession()
qry.routingInfo.lwt = false
Expand All @@ -506,6 +520,10 @@ func (s *Session) Bind(stmt string, b func(q *QueryInfo) ([]interface{}, error))
qry := queryPool.Get().(*Query)
qry.session = s
qry.stmt = stmt
if !qry.disableSkipMetadata && strings.HasPrefix(strings.ToLower(stmt), "select *") {
qry.disableSkipMetadata = true
warnSelectWildcardStartPerformanceIssue()
}
qry.binding = b
qry.defaultsFromSession()
qry.routingInfo.lwt = false
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