Hello. At Thu, 14 Mar 2019 07:17:08 +0000, "Matsumura, Ryo" <matsumura....@jp.fujitsu.com> wrote in <03040DFF97E6E54E88D3BFEE5F5480F737AC390D@G01JPEXMBYT04> > Hi > > I'm afraid that PREPARE of ecpglib is not thread safe. > The following global variables are modified without any locking system. > Is it unnecessary worry? > > [interfaces/ecpg/ecpglib/prepare.c] > static int nextStmtID = 1; > static stmtCacheEntry *stmtCacheEntries = NULL; > static struct declared_statement *g_declared_list;
A connection cannot be concurrently used by multiple threads so the programmer must guard connections using mutex [1] or friends. If it is done by a single mutex (I suppose it is common.), there's no race condition also on the prepared statement storage. I'm not sure it is explicitly aimed but I suppose that there's no problem in a common usage of the library. [1] https://www.postgresql.org/docs/current/ecpg-connect.html > If your application uses multiple threads of execution, they > cannot share a connection concurrently. You must either > explicitly control access to the connection (using mutexes) or > use a connection for each thread. regards. -- Kyotaro Horiguchi NTT Open Source Software Center
