Proposal of Table Partition - Mailing list pgsql-hackers

Hi, everyone! I'd like to propose a postgres partition implementation. First, I would show the design to everyone, and
talkabout it. If we think the design is not very bad, and can be commit to the PostgreSQL baseline, then I will post
thecode to the community.<br />(note: my english is not very good.)<br /><br />Table Partition Design<br
/>=====================<br/>In this design, partitions are normal tables in inheritance hierarchies, with the same
tablestructure with the partitioned table.<br /><br />In pg_class we have an additional relpartition field which has
followingvalues:<br />'s'        /* single regular table */<br />'r'        /* partitioned table by range */<br
/>'l'       /* partitioned table by list */<br />'h'        /* partitioned table by hash */<br />'c'        /* child
partitiontable */<br /><br />Add a new system schema named 'pg_partition', just like 'pg_toast', we can create the
partitioncatalog table to store the partition entries. let's assume the partition catalog's name is pg_partition_2586
(2586is the partitioned table's OID in pg_class).<br />a range or interval partition catalog's structure is as
follows:<br/>column            data type            comment<br />partname        name                a partition's
name,this is the primary key<br />partid            oid                    a partition's OID in pg_class<br
/>interval       text                a interval partition's interval(maybe a expression)<br />partkey1        depends
onpartitioned table<br />...<br />partkeyN        depends on partitioned table<br />partkey1, ..., partkeyN is a
partition'supper bound.<br />Finally, make a unique constraint on partkey1, ..., partkeyN.<br />Every time we create a
newpartition, we insert a new tuple into this partition catalog.<br />Every time we drop an old partition, we delete
therelated tuple in this partition catalog.<br /><br />For a partitioned table's CREATE action, we should transform the
actioninto the CREATE action of partitioned table and partitions, and the INSERT action into the partition catalog.<br
/><br/>For INSERT action, we implement a RelationGetTuplePartid method, which can find the partition the tuple belongs
to.It will do an index scan on the partition catalog table(assume it is pg_partition_2586) to find the partition.<br
/>anda ExecGetPartitionResultRel method, which can return the partition's ResultRelInfo to execute INSERT action.<br
/><br/>For partitioned table's scan action, and JOIN action, we implemented a plan node named 'PartitionExpand'. the
plannode can expand the partitioned table scan node into a list of partitions according to the filter and conditions.
andit can expand partitioned table JOIN node into a list of partitions JOIN node wisely.<br /><br />For pg_dump backup
action,we should dump the partition catalog, and relpartition field in pg_class.<br /><br />so these are the main
pointsof the design, and I can show any detail you wondered later.<br />