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Preload in chunks to avoid mssql parameter limit

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Daniel Hammerschmid 2022-07-14 09:40:24 +02:00 committed by Gerhard Gruber
parent 25fabd9f40
commit a4919ae554
1 changed files with 41 additions and 18 deletions
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39
callback_query_preload.go
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@ -242,16 +242,17 @@ func (scope *Scope) handleBelongsToPreload(field *Field, conditions []interface{
return
}
// find relations
results := makeSlice(field.Struct.Type)
scope.Err(preloadDB.Where(fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relation.AssociationForeignDBNames), toQueryMarks(primaryKeys)), toQueryValues(primaryKeys)...).Find(results, preloadConditions...).Error)
uniquePrimaryKeysMap := map[interface{}]bool{}
for _, key := range toQueryValues(primaryKeys) {
uniquePrimaryKeysMap[indirect(reflect.ValueOf(key)).Interface()] = true
}
// assign find results
var (
resultsValue = indirect(reflect.ValueOf(results))
indirectScopeValue = scope.IndirectValue()
)
uniquePrimaryKeys := make([]interface{}, 0, len(uniquePrimaryKeysMap))
for key := range uniquePrimaryKeysMap {
uniquePrimaryKeys = append(uniquePrimaryKeys, key)
}
indirectScopeValue := scope.IndirectValue()
foreignFieldToObjects := make(map[string][]*reflect.Value)
if indirectScopeValue.Kind() == reflect.Slice {
for j := 0; j < indirectScopeValue.Len(); j++ {
@ -261,6 +262,27 @@ func (scope *Scope) handleBelongsToPreload(field *Field, conditions []interface{
}
}
// need to query relations in chunk of 2000
// to avoid exceeding the mssql parameter limit of 2100
chunkSize := 2000
for i := 0; i < len(uniquePrimaryKeys); i += chunkSize {
var primaryKeyChunk []interface{}
if chunkSize > len(uniquePrimaryKeys)-i {
primaryKeyChunk = uniquePrimaryKeys[i:]
} else {
primaryKeyChunk = uniquePrimaryKeys[i : i+chunkSize]
}
// find relations
results := makeSlice(field.Struct.Type)
queryMarks := "?" + strings.Repeat(",?", len(primaryKeyChunk)-1)
scope.Err(preloadDB.Where(fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relation.AssociationForeignDBNames), queryMarks), primaryKeyChunk...).Find(results, preloadConditions...).Error)
// assign find results
var (
resultsValue = indirect(reflect.ValueOf(results))
)
for i := 0; i < resultsValue.Len(); i++ {
result := resultsValue.Index(i)
if indirectScopeValue.Kind() == reflect.Slice {
@ -274,6 +296,7 @@ func (scope *Scope) handleBelongsToPreload(field *Field, conditions []interface{
scope.Err(field.Set(result))
}
}
}
}
// handleManyToManyPreload used to preload many to many associations