2 messages in com.mysql.lists.bugsRe: Too many connections| From | Sent On | Attachments |
|---|---|---|
| Ronny Melz | 31 May 2005 17:35 | |
| Paul Coldrey | 01 Jun 2005 00:25 |
| Subject: | Re: Too many connections |
|---|---|
| From: | Paul Coldrey (pa...@ensigma.com.au) |
| Date: | 06/01/2005 12:25:47 AM |
| List: | com.mysql.lists.bugs |
Hi Ronny,
To save an email from the mysql big-wigs I'll start with their standard line that "this list is dedicated to repeatable test cases". I strongly suspect they would not see you post as suitably complete to show the presence a bug and allow it to be repeated. Perhaps your message would be better posted to the users list.
Having said that, here are some thoughts that might help you:
The API I have has a function mysql_reap_query(...) which seems to be entirely undocumented, but the source code offers this pearl:
/* send the query and return so we can do something else */ /* needs to be followed by *mysql_reap_query*() when we want to finish processing it */
It appears this function may be deprecated?? If so it raises the question of how does the server know when to free the data created by:
mysql_query( &mysql, query )
It may be the call to:
res = mysql_store_result( &mysql )
triggers the clean up,.. but this doesn't seem intuitive (to me).
Ronny Melz wrote:
Dear all,
I have a problem with the mysql interface for c, which after a couple of hours thinking about bad or faulty programming are eliminated with probability almost 100%.
within a loop, I do a mysql_query(), which is executed and I poll the result and everything is fine. Up to when max_connections of the mysqld is reached: each of the queries leaves after executing a sleeping mysql process behind on the server, which hence throws the "Too many connections" error (or under certain conditions even a "Can't create TCP/IP socket (24)").
Just because of this problem I recently upgraded mysql (including the libraries) from 4.0.21 to 4.1.12, but the problem persisted.
Does anybody have an idea of how to solve this problem? Any suggestions are appreciated.
Best, Ronny
p.s.: code #define GET_W_NR \ "select wort_nr from wortliste where wort_bin='%s' limit 1" MYSQL mysql; MYSQL_RES *res; MYSQL_ROW row; char *query;
init... { mysql_init(&mysql); if ( !mysql_real_connect( &mysql, "127.0.0.1", "username", "passwd", "dbase", 0, "/var/lib/mysql/mysql.sock", 0 ) ) { fprintf(stderr, "Failed: %s\n", mysql_error(&mysql)); } if (!(query = (char*) malloc(256*sizeof(char)))) fprintf(stderr, "no pointer"); }
this is called in a loop and returns with an error after `max_connections` cycles: { sprintf(query, GET_W_NR, refWort); if ( mysql_query( &mysql, query ) ) { fprintf(stderr, "query failed: %s\n", mysql_error(&mysql)); return 0; } if ( !( res = mysql_store_result( &mysql ) ) ) {fprintf(stderr, "store failed: %s\n", mysql_error(&mysql)); return 0;} if ( row = mysql_fetch_row( res ) ) ref_word_nr = atoi(row[0]); else {fprintf(stderr, "fetch failed: %s\n", mysql_error(&mysql)); return 0;} mysql_free_result(res); }
exit... free(query); mysql_close(&mysql);