Question

I am using MAMP and codeigniter framework.

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Am facing a very weird problem. There is an active record statement where i write.

$this->db->select('user_vcard.pro_pic_filename AS `author_pro_pic_filepath`');

If i use AS author_pro_pic_filepath in the CI statement, after executing the HTTP request I get a SERVER ERROR. Then if i try to refresh the page, my browser stalls for a long time and then, at one point, it says

Error Number: 1205.
Lock wait timeout exceeded; try restarting transaction

However, if i replace AS author_pro_pic_filepath with ANY OTHER NAME, it works just fine.

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Here are somethings i tried to do to solve the problem:

1. I exported a .sql dump of the database and kept it in a safe place
2. I tried dropping all tables.
3. I tried dropping the entire database.
4. I cleared all MySQL user privileges from the tables
5. I cleared all cookies, session data from my browser
6. I tried on both Safari and Chrome
7. I tried shutting down MAMP.
8. I tried shutting down my laptop.
9. I tried doing all the above together.
10. I also tried turning off all transaction statements inside my codeigniter code.

No change in result. It is always behaving like I mentioned above.

I have used this same active record statement in several other files in my app. Everywhere it is working fine. But only in this ONE particular file I am facing the issue mentioned above.

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result of SQL query: SHOW ENGINE INNODB MUTEX;

Rows: 2

Type    InnoDB  
Name    /users/severin/MAMPexp/MAMP_packages/mysql-5.5.9/storage/innobase/srv/srv0srv.c:1030    
Status  os_waits=1

Type    InnoDB
Name    /users/severin/MAMPexp/MAMP_packages/mysql-5.5.9/storage/innobase/log/log0log.c:832 
Status  os_waits=7

---

result of SQL query: SHOW ENGINE INNODB MUTEX;

Rows: 1

Type    InnoDB      
Name    
Status  
=====================================
120426 18:39:04 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 5 seconds
-----------------
BACKGROUND THREAD
-----------------
srv_master_thread loops: 56 1_second, 56 sleeps, 5 10_second, 8 background, 8 flush
srv_master_thread log flush and writes: 57
----------
SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 8, signal count 8
Mutex spin waits 2, rounds 31, OS waits 1
RW-shared spins 7, rounds 210, OS waits 7
RW-excl spins 0, rounds 0, OS waits 0
Spin rounds per wait: 15.50 mutex, 30.00 RW-shared, 0.00 RW-excl
------------
TRANSACTIONS
------------
Trx id counter 8BCB
Purge done for trx's n:o < 8BBD undo n:o < 0
History list length 149
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 0, not started, OS thread id 4531712000
MySQL thread id 55, query id 926 localhost root
SHOW ENGINE INNODB STATUS
---TRANSACTION 8BBB, not started, OS thread id 4531163136
MySQL thread id 44, query id 820 localhost doc2doc
---TRANSACTION 8BBD, ACTIVE 486 sec, OS thread id 4531437568
3 lock struct(s), heap size 376, 2 row lock(s), undo log entries 1
MySQL thread id 45, query id 831 localhost doc2doc
Trx read view will not see trx with id >= 8BBE, sees < 8BBE
--------
FILE I/O
--------
I/O thread 0 state: waiting for i/o request (insert buffer thread)
I/O thread 1 state: waiting for i/o request (log thread)
I/O thread 2 state: waiting for i/o request (read thread)
I/O thread 3 state: waiting for i/o request (read thread)
I/O thread 4 state: waiting for i/o request (read thread)
I/O thread 5 state: waiting for i/o request (read thread)
I/O thread 6 state: waiting for i/o request (write thread)
I/O thread 7 state: waiting for i/o request (write thread)
I/O thread 8 state: waiting for i/o request (write thread)
I/O thread 9 state: waiting for i/o request (write thread)
Pending normal aio reads: 0 [0, 0, 0, 0] , aio writes: 0 [0, 0, 0, 0] ,
ibuf aio reads: 0, log i/o's: 0, sync i/o's: 0
Pending flushes (fsync) log: 0; buffer pool: 0
413 OS file reads, 520 OS file writes, 381 OS fsyncs
0.00 reads/s, 0 avg bytes/read, 0.00 writes/s, 0.00 fsyncs/s
-------------------------------------
INSERT BUFFER AND ADAPTIVE HASH INDEX
-------------------------------------
Ibuf: size 1, free list len 0, seg size 2, 0 merges
merged operations:
insert 0, delete mark 0, delete 0
discarded operations:
insert 0, delete mark 0, delete 0
Hash table size 276707, node heap has 1 buffer(s)
0.00 hash searches/s, 0.00 non-hash searches/s
---
LOG
---
Log sequence number 5050799
Log flushed up to   5050799
Last checkpoint at  5050799
0 pending log writes, 0 pending chkp writes
370 log i/o's done, 0.00 log i/o's/second
----------------------
BUFFER POOL AND MEMORY
----------------------
Total memory allocated 137363456; in additional pool allocated 0
Dictionary memory allocated 114130
Buffer pool size   8192
Free buffers       7736
Database pages     455
Old database pages 0
Modified db pages  0
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 0, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 402, created 53, written 322
0.00 reads/s, 0.00 creates/s, 0.00 writes/s
Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000
Pages read ahead 0.00/s, evicted without access 0.00/s
LRU len: 455, unzip_LRU len: 0
I/O sum[0]:cur[0], unzip sum[0]:cur[0]
--------------
ROW OPERATIONS
--------------
0 queries inside InnoDB, 0 queries in queue
2 read views open inside InnoDB
Main thread id 4506259456, state: waiting for server activity
Number of rows inserted 507, updated 2, deleted 0, read 1679
0.00 inserts/s, 0.00 updates/s, 0.00 deletes/s, 0.00 reads/s
----------------------------
END OF INNODB MONITOR OUTPUT
============================

Answer 1

OMG……….. I have just proven myself to be a big time dumb ass after having spent 2 days trying to figure this out.

I was calling a helper function while I had not loaded the helper beforehand.

Pardon my idiocy.