python - memory usage, how to free memory

Question

I am using python and when indexing documents (for search engine) it takes a lot of RAM, after i stop the indexing process the memory is still full (like 8gb of RAM). This is bad because i need my search engine to work all the time and not to reset the OS when i finished indexing. Is there any efficient way how to manage with huge arrays,dictionaries and lists, and how to free them. Any ideas?

I saw also some questions about it on stackoverflow, but they are old:

Python memory footprint vs. heap size

Profile Memory Allocation in Python (with support for Numpy arrays)

Info:

free -t
             total       used       free     shared    buffers     cached
Mem:          5839       5724        114          0         15       1011
-/+ buffers/cache:       4698       1141
Swap:         1021        186        835
Total:        6861       5910        950


top | grep python 

 3164 root      20   0 68748  31m 1404 R   17  0.5  53:43.89 python                                                                     
 6716 baddc0re  20   0 84788  30m 1692 S    0  0.5   0:06.81 python     

 ps aux | grep python

root      3164 57.1  0.4  64876 29824 pts/0    R+   May27  54:23 python SE_doc_parse.py
baddc0re  6693  0.0  0.2  53240 16224 pts/1    S+   00:46   0:00 python index.py

uptime

01:02:40 up  1:43,  3 users,  load average: 1.22, 1.46, 1.39


sysctl vm.min_free_kbytes

vm.min_free_kbytes = 67584

The real problem is when i start the script the indexing is fast, but when the usage is increasing it is getting slower.

Document wikidoc_18784 added on 2012-05-28 01:03:46 "fast"
wikidoc_18784
-----------------------------------
Document wikidoc_21934 added on 2012-05-28 01:04:00 "slower"
wikidoc_21934
-----------------------------------
Document wikidoc_22903 added on 2012-05-28 01:04:01 "slower"
wikidoc_22903
-----------------------------------
Document wikidoc_20274 added on 2012-05-28 01:04:10 "slower"
wikidoc_20274
-----------------------------------
Document wikidoc_23013 added on 2012-05-28 01:04:53  "even more slower"
wikidoc_23013

The size of the documents is one or two pages of text maximum. The indexing of 10 pages takes about 2-3 seconds.

Tnx everyone for the help :)

Answer 1

From discussion it seems you are storing the data in nothing but a giant huge dict (not often I get to say that with a straight face ;) ) Maybe offsetting the data onto a proper database like redis might reduce the memory usage of python. It might also make your data more efficient and faster to work with.