Thread: send()/receive() and on-disk storage
Hi, Currently, there's a discussion on the pljava list, and we're confused about a small detail: Does PostgreSQL call the datatypes' defined send() function before storing the tuple data in the table, on disk, and call receive() when reading it again? My position was that send()/receive() are only used for client communication in the V3 protocol binary mode, and COPY in binary mode, but the backend stores them in the tables as_is (modulo compression/ TOASTing). Is my assumption correct? Btw, I'm going to triple-check this in the source and via tests, too. Thanks, Markus -- Markus Schaber | Logical Tracking&Tracing International AG Dipl. Inf. | Software Development GIS Fight against software patents in Europe! www.ffii.org www.nosoftwarepatents.org
On Fri, Sep 29, 2006 at 03:44:07PM +0200, Markus Schaber wrote: > Does PostgreSQL call the datatypes' defined send() function before > storing the tuple data in the table, on disk, and call receive() when > reading it again? No. > My position was that send()/receive() are only used for client > communication in the V3 protocol binary mode, and COPY in binary mode, > but the backend stores them in the tables as_is (modulo compression/ > TOASTing). Yes. It would be terribly inefficient to call those functions for each read/write. The disk has the internal format, send/receive deal with a portable not-host-dependant representation of the data. Have a nice day, -- Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/ > From each according to his ability. To each according to his ability to litigate.
Hi, Martijn, Martijn van Oosterhout wrote: > It would be terribly inefficient to call those functions for each > read/write. The disk has the internal format, send/receive deal with a > portable not-host-dependant representation of the data. Thanks. Markus -- Markus Schaber | Logical Tracking&Tracing International AG Dipl. Inf. | Software Development GIS Fight against software patents in Europe! www.ffii.org www.nosoftwarepatents.org