在PostgreSQL中创建函数时遇到"undefined symbol: Float8GetDatum“

Question

我使用的是redhat linux 7.3中的PostgreSQL11.5。在sql脚本中，该函数的创建方式如下：

create or replace function alpine_miner_float_array_sum_accum(state float[], ind float[])
returns float[]
AS 'alpine_miner', 'alpine_miner_float_array_sum_accum'
language C immutable;

但它会给出以下错误：

ERROR:  could not load library "/usr/pgsql-11/lib/alpine_miner.so": /usr/pgsql-11/lib/alpine_miner.so: undefined symbol: Float8GetDatum
SQL state: XX000

我发现/usr/pgsql-11/lib/alpine_min.so确实存在，ld命令的输出如下：

linux-vdso.so.1 =>  (0x00007ffda65d6000)
libc.so.6 => /lib64/libc.so.6 (0x00007eff25a67000)
/lib64/ld-linux-x86-64.so.2 (0x00007eff26051000)

ldd命令：

ld: warning: cannot find entry symbol _start; not setting start address
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `construct_md_array'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `get_call_result_type'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `ArrayGetNItems'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `logf'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `deconstruct_array'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `CurrentMemoryContext'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `acosf'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `GetAttributeByName'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `elog_finish'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `errstart'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `pg_detoast_datum'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `exp'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `sqrtf'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `MemoryContextAllocZero'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `elog_start'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `errmsg'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `BlessTupleDesc'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `get_typlenbyvalalign'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `Float8GetDatum'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `log'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `pow'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `errdetail'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `DatumGetFloat8'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `errfinish'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `sqrt'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `heap_form_tuple'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `format_procedure'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `construct_array'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `MemoryContextAlloc'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `pfree'
/usr/pgsql-11/lib/alpine_miner.so: undefined reference to `errcode'

你有什么想法吗？提前谢谢。

Answer 1

在构建alpine_miner.so时，您是在一个PostgreSQL安装的基础上构建它的，该安装的配置与您尝试使用它的安装不同。

在标题问题的情况下，alpine_miner.so是使用未定义的USE_FLOAT8_BYVAL构建的，但您的PostgreSQL已经定义了它：

#ifdef USE_FLOAT8_BYVAL
static inline Datum
Float8GetDatum(float8 X)
{
        union
        {
                float8          value;
                int64           retval;
        }                       myunion;

        myunion.value = X;
        return Int64GetDatum(myunion.retval);
}
#else
extern Datum Float8GetDatum(float8 X);
#endif

但未定义的链接器引用列表还表明，您正在尝试将共享对象加载到旧的或修改过的PostgreSQL中：

例如，自2004年4月提交375369acd1c以来，BlessTupleDesc一直在服务器中。

要获得进一步的帮助，您必须公开PostgreSQL的确切制造商和版本以及alpine_miner.so的确切构建过程。