CODEWITHSUNDEEP
phpmemoryphpexcel
Chris Utter
Chris Utter

Reputation: 143

PHPExcel not releasing memory

I have a script which reads emails with Excel files attached.
I am using PHPExcel to parse these files.

The current problem I am having, is with an email which has five spreadsheets attached.
Each time the fifth file is loaded, PHP runs out of memory.

Initially I tried nullifying ($objPHPExcel = NULL;) and unsetting (unset($objPHPExcel);) the PHPExcel Object each time after I was through with it. That didn't help.

I then tried adding garbage collection to the process (gc_enable(); $cycles_collected = gc_collect_cycles();). That didn't help.

I printed the current php memory usage to my error log and I can see it grow with the loading of each Excel file into PHPExcel, I also can see that the memory usage does not decrease with each NULL, unset or gc_collect.

Here is some of the sample output to my error_log right before and after PHP runs out of memory:

[17-Aug-2017 16:04:29 America/Chicago] [Blackouts] Current Memory Usage at beginning of script before loading Excel file: 85575176

[17-Aug-2017 16:04:32 America/Chicago] [Blackouts] Current Memory Usage after loading Excel file: 104474632

[17-Aug-2017 16:04:34 America/Chicago] [Blackouts] Current Memory Usage after parsing of Excel file is complete: 104480416

[17-Aug-2017 16:04:34 America/Chicago] [Blackouts] Current Memory Usage after PHPExcel object set to null: 104480536

[17-Aug-2017 16:04:34 America/Chicago] [Blackouts] Current Memory Usage after PHPExcel object is unset: 104480256

[17-Aug-2017 16:04:34 America/Chicago] [Blackouts] gc collected cycles: 0

[17-Aug-2017 16:04:34 America/Chicago] [Blackouts] Current Memory Usage after gc_collect_cycles: 104480416

[17-Aug-2017 16:04:34 America/Chicago] [Blackouts] script completed: /path/to/file/Schedule Week of 14 Aug 2017 - 21 Aug 2017.xlsx

[17-Aug-2017 16:04:34 America/Chicago] [Blackouts] Current Memory Usage at beginning of script before loading Excel file: 104484072

[17-Aug-2017 16:04:36 America/Chicago] [Blackouts] Current Memory Usage after loading Excel file: 122069128

[17-Aug-2017 16:04:38 America/Chicago] [Blackouts] Current Memory Usage after parsing of Excel file is complete: 122114480

[17-Aug-2017 16:04:38 America/Chicago] [Blackouts] Current Memory Usage after PHPExcel object set to null: 122114600

[17-Aug-2017 16:04:38 America/Chicago] [Blackouts] Current Memory Usage after PHPExcel object is unset: 122114320

[17-Aug-2017 16:04:38 America/Chicago] [Blackouts] gc collected cycles: 0

[17-Aug-2017 16:04:38 America/Chicago] [Blackouts] Current Memory Usage after gc_collect_cycles: 122114480

[17-Aug-2017 16:04:38 America/Chicago] [Blackouts] script completed: /path/to/file/Schedules Week of 14 Aug 2017 - 21 Aug 2017.xlsx

[17-Aug-2017 16:04:38 America/Chicago] [Blackouts] Current Memory Usage at beginning of script before loading Excel file: 122118192

[17-Aug-2017 16:04:39 America/Chicago] PHP Fatal error:  Allowed memory size of 134217728 bytes exhausted at Zend/zend_vm_execute.h:22207 (tried to allocate 72 bytes) in /mnt/nas_001_www/Classes/PHPExcel/Cell.php on line 551

Upvotes: 1

Views: 2597

Answers (1)

Mark Baker
Mark Baker

Reputation: 212522

You cannot simply nullify or unset a PHPExcel object to remove it from memory, as explained in the documentation, because it contains cyclic references (the workbook contains a collection of worksheet objects, and each worksheet references the workbook; and similarly with worksheet and cell objects) that cannot simply be resolved by an unset. Instead, you need to break those references first

$objPHPExcel->disconnectWorksheets();
unset($objPHPExcel)

Upvotes: 7

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