Hello. At Mon, 22 Jul 2019 02:28:22 +0000, "Matsumura, Ryo" <matsumura....@jp.fujitsu.com> wrote in <03040DFF97E6E54E88D3BFEE5F5480F74AC15BBD@G01JPEXMBYT04> > Hi > > # I rewrote my previous mail. > > PQconnectPoll() is used as method for asynchronous using externally or > internally. > If a caller confirms a socket ready for writing or reading that is > requested by return value of previous PQconnectPoll(), next PQconnectPoll() > must not be blocked. But if the caller specifies target_session_attrs to > 'read-write', PQconnectPoll() may be blocked. > > Detail: > If target_session_attrs is set to read-write, PQconnectPoll() calls > PQsendQuery("SHOW transaction_read_only") althogh previous return value was > PGRES_POLLING_READING not WRITING. > In result, PQsendQuery() may be blocked in pqsecure_raw_write(). > > I attach a patch. > > Regards > Ryo Matsumura
First, this patch looks broken. patched> if (conn->sversion >= 70400 && patched> conn->target_session_attrs != NULL && patched> strcmp(conn->target_session_attrs, "read-write") == 0) patched> { patched> } Perhaps you did cut-n-paste instead of copy-n-paste. I'm not sure such a small write just after reading can block, but doing that makes things tidy. You also need to update the corresponding documentation. regards. -- Kyotaro Horiguchi NTT Open Source Software Center