Question

我有一个用户定义的类型 mytype ：

CREATE TYPE mytype AS (
    value1 integer
);

我想使用C函数返回mytype。这是我写的：

#include "postgres.h"
#include "fmgr.h"
#include "funcapi.h"
#include "catalog/pg_type.h"

#ifdef PG_MODULE_MAGIC
PG_MODULE_MAGIC;
#endif

PG_FUNCTION_INFO_V1(testfunc);

Datum
testfunc(PG_FUNCTION_ARGS) {
    TupleDesc   tupdesc;
    Datum       values[1];
    bool        nulls[1];

    MemSet(values, 0, sizeof(values));
    MemSet(nulls, 0, sizeof(nulls));

    tupdesc = CreateTemplateTupleDesc(1, false);
    TupleDescInitEntry(tupdesc, (AttrNumber) 1, "value1", INT4OID, -1, 0);

    tupdesc = BlessTupleDesc(tupdesc);

    values[0] = Int32GetDatum(100);

    HeapTuple rettuple = heap_form_tuple( tupdesc, values, nulls );
    PG_RETURN_DATUM( HeapTupleGetDatum( rettuple ) );
}

SQL参考：

CREATE OR REPLACE FUNCTION testfunc() RETURNS mytype AS 'path/to/library.so', 'testfunc' LANGUAGE C STRICT;

现在，当我尝试测试我的功能时，它会崩溃连接：

postgres=# SELECT testfunc();
SSL SYSCALL error: EOF detected
The connection to the server was lost. Attempting reset: Failed.

请告诉我我在哪里做错了。

服务器日志：

2017-01-12 18:47:45 IST LOG:  server process (PID 25208) was terminated by signal 11: Segmentation fault
2017-01-12 18:47:45 IST DETAIL:  Failed process was running: SELECT testfunc();
2017-01-12 18:47:45 IST LOG:  terminating any other active server processes
2017-01-12 18:47:45 IST WARNING:  terminating connection because of crash of another server process
2017-01-12 18:47:45 IST DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2017-01-12 18:47:45 IST HINT:  In a moment you should be able to reconnect to the database and repeat your command.
2017-01-12 18:47:45 IST FATAL:  the database system is in recovery mode
2017-01-12 18:47:45 IST LOG:  all server processes terminated; reinitializing
2017-01-12 18:47:45 IST LOG:  database system was interrupted; last known up at 2017-01-12 18:45:10 IST
2017-01-12 18:47:45 IST FATAL:  the database system is in recovery mode
2017-01-12 18:47:45 IST LOG:  database system was not properly shut down; automatic recovery in progress
2017-01-12 18:47:46 IST LOG:  record with zero length at 0/1C692E8
2017-01-12 18:47:46 IST LOG:  redo is not required
2017-01-12 18:47:46 IST LOG:  MultiXact member wraparound protections are now enabled
2017-01-12 18:47:46 IST LOG:  database system is ready to accept connections
2017-01-12 18:47:46 IST LOG:  autovacuum launcher started

我参考了this和this

在Postgres C函数中返回Composite-type

0 个答案: