Hello:
I find that the real timestamp format(got from the file which is produced by copying binary to ) is different from what i find in timestamp_send func.

i do think that the binary format of a timestamp "2006-04-18 11:20:20" should be "44 2B B0 6A 00 00 00 00" standing for "secs:1143713898, usecs:0" but in fact it is:"41A7 7DBA D400 0000 "

timestamp is defined as int64 or float8, when it is defined as int64, it looks like timeval, first 32 bits for seconds,second 32 bits for usec.
and from the timestamp_send func, it just changes the first 32 bits to binary then combines the next 32 bits

/* codes from timestamp_send
*/

Datum
timestamp_send(PG_FUNCTION_ARGS)
{
Timestamp timestamp = PG_GETARG_TIMESTAMP(0);
StringInfoData buf;

pq_begintypsend(&buf);
#ifdef HAVE_INT64_TIMESTAMP
pq_sendint64(&buf, timestamp);
#else
pq_sendfloat8(&buf, timestamp);
#endif
PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}

/* codes from pq_sendint64
*/
void
pq_sendint64(StringInfo buf, int64 i)
{
uint32 n32;

/* High order half first, since we're doing MSB-first */
#ifdef INT64_IS_BUSTED
/* don't try a right shift of 32 on a 32-bit word */
n32 = (i < 0) ? -1 : 0;
#else
n32 = (uint32) (i >> 32);
#endif
n32 = htonl(n32);
appendBinaryStringInfo(buf, (char *) &n32, 4);

/* Now the low order half */
n32 = (uint32) i;
n32 = htonl(n32);
appendBinaryStringInfo(buf, (char *) &n32, 4);
}


so i do think that the binary format of a timestamp "2006-04-18 11:20:20" should be "44 2B B0 6A 00 00 00 00" standing for "secs:1143713898, usecs:0"

but in fact it is:" 41A7 7DBA D400 0000 " , i don't know why.

maybe, i have looked into a wrong func, then which is the right one?


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"energumen@buaa.edu.cn" <energumen@buaa.edu.cn> writes:
> timestamp is defined as int64 or float8, when it is defined as int64, it looks like timeval, first 32 bits for seconds,second 32 bits for usec.

No, it's seconds times 1000000, not times 2^32.

regards, tom lane

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