/// <summary>
/// Creates a necessary partition if it does not exist.
/// </summary>
public static void CreatePartition(NpgsqlConnection conn, string tableName,
DateTime today, PartitionSize partitionSize, out string partitionName)
{
DateTime startDate;
DateTime endDate;
if (partitionSize == PartitionSize.OneMonth)
{
startDate = new DateTime(today.Year, today.Month, 1, 0, 0, 0, DateTimeKind.Utc);
endDate = startDate.AddMonths(1);
}
else // PartitionSize.OneYear
{
startDate = new DateTime(today.Year, 1, 1, 0, 0, 0, DateTimeKind.Utc);
endDate = startDate.AddYears(1);
}
partitionName = tableName +
"_" + startDate.ToString(PartitionDateFormat) +
"_" + endDate.ToString(PartitionDateFormat);
new NpgsqlCommand(
$"CREATE TABLE IF NOT EXISTS {partitionName} PARTITION OF {tableName} " +
$"FOR VALUES FROM('{startDate:yyyy-MM-dd} 00:00:00Z') TO ('{endDate:yyyy-MM-dd} 00:00:00Z')",
conn).ExecuteNonQuery();
}
public static IEnumerable <IReadOnlyCollection <T> > PartitionUnique <T>([NotNull] this ICollection <T> thisValue, int size, PartitionSize type, IEqualityComparer <T> comparer = null)
{
if (size < 0)
{
throw new ArgumentOutOfRangeException(nameof(size));
}
if (size == 0 || thisValue.Count == 0)
{
return(Enumerable.Empty <IReadOnlyCollection <T> >());
}
if (type == PartitionSize.TotalCount)
{
size = (int)Math.Ceiling(thisValue.Count / (double)size);
}
return(thisValue.PartitionUnique(size, comparer));
}
public static IEnumerable <IDictionary <TKey, TValue> > Partition <TKey, TValue>([NotNull] this IDictionary <TKey, TValue> thisValue, int size, PartitionSize type = PartitionSize.PerPartition)
{
if (size < 0)
{
throw new ArgumentOutOfRangeException(nameof(size));
}
if (size == 0 || thisValue.Count == 0)
{
yield break;
}
int sz;
switch (type)
{
case PartitionSize.TotalCount:
sz = (int)Math.Ceiling(thisValue.Count / (double)size);
break;
default:
sz = size;
break;
}
int n = 0;
IDictionary <TKey, TValue> dictionary = new Dictionary <TKey, TValue>(sz);
foreach (KeyValuePair <TKey, TValue> item in thisValue)
{
dictionary.Add(item);
n++;
if (n == thisValue.Count || dictionary.Count == sz)
{
yield return(dictionary);
dictionary.Clear();
}
}
}