Hi, Julien Rouhaund, who has proposed a patch for partition-wise ordering mentioned to me offlist that the comments for PartitionBoundInfoData do not mention the fact that the datums in datums array are ordered. I think that's important to mention there. So here's patch to do that.
The comment I have added refers to the functions which order the datums, since every partition kind has different method of ordering datums and I think the prologue is not a suitable place to explain that ordering. I have added a sentence for range and list partitioning since the ordering is easier to explain in those cases. Also added a sentence about canonical PartitionBoundInfoData without using that word. -- Best Wishes, Ashutosh Bapat EnterpriseDB Corporation The Postgres Database Company
diff --git a/src/backend/catalog/partition.c b/src/backend/catalog/partition.c index dd4a8d3..865f572 100644 --- a/src/backend/catalog/partition.c +++ b/src/backend/catalog/partition.c @@ -72,6 +72,13 @@ * of datum-tuples with 2 datums, modulus and remainder, corresponding to a * given partition. * + * The datums in datums array are arranged in the increasing order defined by + * functions qsort_partition_rbound_cmp(), qsort_partition_list_value_cmp() and + * qsort_partition_hbound_cmp() for range, list and hash partitioned tables + * resp. For range and list partitions this simply means that the datums in the + * datums array are arranged in the increasing order defined by the partition + * key collation. + * * In the case of list partitioning, the indexes array stores one entry for * every datum, which is the index of the partition that accepts a given datum. * In case of range partitioning, it stores one entry per distinct range @@ -82,6 +89,9 @@ * partition which would accept that datum-tuple would be given by the entry * pointed by remainder produced when hash value of the datum-tuple is divided * by the greatest modulus. + * + * PartitionBoundInfoData structures for two partitioned table with exactly same + * bounds look exactly same. */ typedef struct PartitionBoundInfoData
