Nagib Abi Fadel wrote:
So considering those facts, it would be better to use the Sequence Method, since it would only require cleaning up one table .... Or is there anything else i am missing ???
It is becoming more of a toss-op. Prior to 7.4, the system indexes would grow until a manual REINDEX was issued in a stand-alone backend. In 7.4, the dead tuples remain, but at least can be re-used once they've been marked that way by the occassional vacuum. autovacuum will tend to make dead-tuple reclaimation transparent, like Oracle.
The absolutely cheapest method is to write a pair of functions in 'C' that sets/gets a global variable:
#include "postgres.h" #include "fmgr.h"
#define MAX_DATA 64
char session_data[MAX_DATA] = "";
PG_FUNCTION_INFO_V1(setvalue);
Datum setvalue(PG_FUNCTION_ARGS) {text *value; long len;
value = PG_GETARG_TEXT_P(0);
len = VARSIZE(value) - VARHDRSZ;
if (len >= MAX_DATA) {
elog(ERROR, "setvalue: value too long: %li", len);
}
memcpy(session_data, VARDATA(value), len);
session_data[len] = 0;PG_RETURN_BOOL(true);
}
PG_FUNCTION_INFO_V1(getvalue);
Datum getvalue(PG_FUNCTION_ARGS) {text *result; long len;
len = strlen(session_data) + VARHDRSZ; result = (text *) palloc(len); VARATT_SIZEP(result) = len; memcpy(VARDATA(result), session_data, len - VARHDRSZ);
PG_RETURN_TEXT_P(result);
}
-- Compile
gcc -c example.c -I/usr/include/pgsql/server gcc -shared -o pgexample.so pgexample.o
-- Install somewhere PostgreSQL can get at it
cp pgexample.so /usr/local/mypglibs
-- Create the functions where path-to-lib is the path to -- the shared library.
CREATE OR REPLACE FUNCTION setvalue(text) RETURNS boolean AS '/usr/local/mypglibs/pgexample.so' LANGUAGE 'C' WITH (isStrict);
CREATE OR REPLACE FUNCTION getvalue() RETURNS text AS '/usr/local/mypglibs/pgexample.so' LANGUAGE 'C' WITH (isStrict);
Now all you need to to is invoke setvalue() at the start of the session, and build views around getvalue():
CREATE VIEW v_foo AS SELECT * FROM foo WHERE foo.key = getvalue();
At the start of a session:
SELECT setvalue('Mike Mascari was here');Hope that helps,
Mike Mascari
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