[pgpool-hackers: 2794] Reducing amount of debugging messages

[Tatsuo Ishii]

Currently most of debugging messages are marked as DEBUG1.  As of
today we have 620 ereport(DEBUG...) lines.  Out of 620 lines, 542 are
DEBUG1. As a result if enable DEBUG1 message emitted, considerably
large amount of log file is generated.

For example if I run pgbench just for 10 seconds:

    pgbench -p 11000 -c 10 -M extended test

18MB of log file is generated. I analyzed the log file to find out
what debug messages are often used.

$ grep -v DETAIL pgpool.log > pgpool.log-without-DETAIL 
$ awk '{print $6}' pgpool.log-without-DETAIL| awk '{count[$0]++}END{for(i in count)print count[i], i}'|sort -nr

27265 session
21644 pool_virtual_master_db_node_id:
18288 pool_write:
14785 reading
11620 pushing
10101 processing
10100 read_kind_from_backend:
9987 pool_flush_it:
6020 pool_wait_till_ready_for_query:
3642 read_kind_from_backend
3600 pool_pending_message_head_message:
3500 pool_pending_message_pull_out:
3500 pool_pending_message_add:
3146 DB
2944 while
2800 called
2500 Execute:
2202 SimpleForwardToFrontend:
1963 pool_read:
1950 do_query:
1560 pool_send_and_wait:
1400 pop
1380 adding
902 checking
715 pool_query_context_destroy:
715 decide
700 Parse:
700 Describe:
700 Bind:
500 parse
400 not
220 process
62 detect
54 authenticate
49 initializing
47 I
45 verify_backend_node_status:
37 shmem_exit(-1):
37 proc_exit(-1):
30 authentication
24 health
21 waiting
20 creating
12 comparing
11 setting
11 sending
11 selecting
11 RESET
11 Frontend
10 node
10 do_command:
2 get_server_version:
2 function
2 find_primary_node:
2 backend
1 unlogged
1 temporary
1 system
1 pool_coninfo_size:
1 pgpool-II
1 make
1 find_primary_node_repeatedly:
1 Setting
1 Request
1 Recovery
1 ProcessInfo:
1 Backend

I have eliminated top 15 or so messages by downgrading them to
DEBUG5. Now I get 1.1 MB log file for the same pgbench run if I set
"log_min_messages = DEBUG1".  Attached is the patch for this. I would
like to commit the patch if there's no objection.

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp
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