Hallow hackers I have the following problem to solve and would like to get advice on the best way to do it.
The problem: When growing a pl/proxy based database cluster, one of the main operations is splitting a partition. The standard flow is as follows: 1) make a copy of the partitions table(s) to another database 2) reconfigure pl/proxy to use 2 partitions instead of one The easy part is making a copy of all or half of the table to another database. The hard part is fast deletion (i mean milliseconds, comparable to TRUNCATE) the data that should not be in a partition (so that RUN ON ALL functions will continue to return right results). It would be relatively easy, if we still had the RULES for select available for plain tables, but even then the eventual cleanup would usually mean at least 3 passes of disk writes (set xmax, write deleted flag, vacuum and remove) What I would like to have is possibility for additional visibility checks, which would run some simple C function over tuple data (usually hash(fieldval) + and + or ) and return visibility (is in this partition) as a result. It would be best if this is run at so low level that also vacuum would use it and can clean up the foreign partition data in one pass, without doing the delete dance first. So finally the QUESTION : where in code would be the best place to check for this so that 1) both regular queries and VACUUM see it 2) the tuple data (and not only system fields or just xmin/xmax) would be available for the function to use -- ------- Hannu Krosing PostgreSQL Unlimited Scalability and Performance Consultant 2ndQuadrant Nordic PG Admin Book: http://www.2ndQuadrant.com/books/ -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
