Error of allocating memory for just a simple XQuery update

I have a php script which has a loop, in which, there is a XQuery update command issued to Tamino databsae to insert a new attribute to a existing element. Since I didn’t use any transaction control, so each time the command is executed, it commit automatically. However, sometimes I get Tamino Error saying it cann’t allocate memory failed. I use “top” to check, and find out that there are up to 12 “inosrv” process running at the same time, each of which use a lot of memory. could anybody tell me why is this happening? How can I avoid the memory allocation error. The loop loops about 1000 times. Each time it insert a new attribute to a different element in the same document. PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME CPU COMMAND 4380 sag 17 0 630M 630M 340M S 8.3 31.3 1:42 1 inosrv 4372 sag 15 0 630M 630M 340M S 2.0 31.3 5:31 2 inosrv 4373 sag 15 0 630M 630M 340M S 1.8 31.3 5:32 2 inosrv 4367 sag 15 0 630M 630M 340M S 1.7 31.3 5:33 2 inosrv 4368 sag 15 0 630M 630M 340M S 1.6 31.3 5:34 2 inosrv 4370 sag 15 0 630M 630M 340M S 1.6 31.3 5:33 2 inosrv 4371 sag 15 0 630M 630M 340M S 1.6 31.3 5:35 2 inosrv 4374 sag 16 0 630M 630M 340M S 1.5 31.3 5:33 0 inosrv 4366 sag 15 0 630M 630M 340M S 1.4 31.3 5:33 2 inosrv 4369 sag 15 0 630M 630M 340M R 1.4 31.3 5:33 2 inosrv 4375 sag 15 0 630M 630M 340M S 1.4 31.3 5:31 0 inosrv

Do you happend to have 12 running databases on your server ?

Noop. When I started the application, those process showed up together, when the process is done, all the process is disappeard