After hours of trying and searching, I am hoping someone can help with my issue.
I created a CSV upload which works great on small numbers(at least 100 works fine). When testing a file with 2,000 records or so, I get an error of "Connect Error: SQLSTATE[08004] [1040] Too many connections".
From what I can tell, this error can be resolved by closing my DB connection after insert, which I can not figure out how to do in Zend 2, all the results are for Zend 1.
If there is a better way to insert large records into MySQL from CSV, then I am open to those suggestions as well.
My controller code:
while ($line = fgetcsv($fp, 0, ",")){
$record = array_combine($header, $line);
$record['group_id'] = $extra1;
$employee->exchangeArray($record);
$this->getEmployeeTable()->saveEmployee($employee);
}
And my saveEmployee code is just a basic Insert:
$adapter = new Adapter($dbAdapterConfig);
$sql = "INSERT INTO......;
$resultSet = $adapter->query($sql, \Zend\Db\Adapter\Adapter::QUERY_MODE_EXECUTE);
I believe adding a closeconnection() or something after $resultSet would resolve my issue.
On every iteration you call your saveEmployee method so on every iteration you make a new instance of Adapter.
Move your Adapter initialization out of the while loop (before the loop) and you should be fine.
Related
I noticed large amout of sessions running on database. Almost half of them have a query, take a look at . In my project I use queue worker to execute a code in background and use database as queue connection.
Here is the code I use:
Passing jobs to Batch:
$jobs = [];
foreach($data as $d){
$jobs[] = new EstimateImportJob($d);
}
$batch = Bus::batch($jobs)->dispatch();
Job source code:
$current_date = Carbon::now();
// Using these as tables don`t have increment traits
$last_po_id = \DB::connection("main")->table('PO')->latest('ID')->first()->ID;
$last_poline_id = \DB::connection("main")->table('POLINE')->latest('ID')->first()->ID;
$last_poline_poline = \DB::connection("main")->table('POLINE')->latest('POLINE')->first()->POLINE;
\DB::connection('main')->table('POLINE')->insert($d);
As I know Laravel is supposed to close DB connection after code executions is finished. But I can`t find a reason why I have so many database sessions. Any ideas would be appretiated!
Normally, even with working queue worker expected result is to have 3-4 database sessions.
I'm trying to get ADODB caching to work. I have a php script where i define the DB connection.
global $conn;
$conn = new COM ("ADODB.Connection");
$connStr = "PROVIDER-SQLOLEDB;SERVER=;UID=;PWD=;DATABASE=);
$conn->open($connStr);
I left the unnecessary details out of the picture.
Then in some other script i import the connection.php, and then try to make a normal query.
$query = "SELECT * from table where some_id = 21540 and other_id = BOGUS_INFO"
$rs = $GLOBALS['conn']->CacheExecute(60,$query);
This returns Uncaught exception 'com_exception'.. ADODB.Connection Arguments are of the wrong type,are out of acceptable range, or are in conflict with another.
I'm baffled because the next line of code works flawlessly.
$rs = $GLOBALS['conn']->execute($query); //OK!
Any ideeas?
I also tried CacheGetOne but i get the same error.
Could it be from the way i defined this thing below? (it's literally like that in my code)
$GLOBALS['ADODB_CACHE_DIR']=$_SERVER['DOCUMENT_ROOT'].'/../cache/adodb';
Well after alot of hassle, i kinda found an answer by choosing another way of doing things. I downloaded the latest ADODB build. Inserted it in my project, and modified files accordingly:
The connection.php changed to:
require('PATH/adodb.inc.php');
require('PATH/adodb-csvlib.inc.php');//read somewhere that i need this for the caching executes
$GLOBALS['ADODB_CACHE_DIR'] = $_SERVER['DOCUMENT_ROOT'].'/cache/adodb';
global $ADODB_CACHE_DIR; //don't know which one adodb usese really to identify cache directory so for safety - both
$ADODB_CACHE_DIR = $_SERVER['DOCUMENT_ROOT'].'/cache/adodb';
$conn = NewADOConnection('mssqlnative');//i tried first with mssql simple but script terminated execution on execute() attempt.. no error.. no nothing.. no output .. strange
$conn->Connect($myServer, $myUser, $myPass, $myDb);
After that i had to fiddle a bit with the code because,
$rs = $conn->CacheExecute(time,query)
returns Adodbrecordset_array_mssqlnative Object, and not an array, and, in my code i used to display and manipulate values as
while (!$rs->EOF) {
$rs['row']->value;
$rs->MoveNext();
}
and now they should be
$rs->fields['row'];
Another tricky thing was getting the fields array to be associated to the names of the columns in my query, but after a short search i discovered
$GLOBALS['conn']->SetFetchMode(ADODB_FETCH_ASSOC);
and voila! Everything works, even the caching.
It took script execution times with this bare optimisation from 1 sec to 0.1 or even 0.005 sometimes.
I'm having an intermittent problem with quite a complex search system. Every once in a while a PHP Daemon I wrote, which adds new content to our database and an RT index for sphinx throws a mysterious exception.
Message is simply "Statement could not be executed".
The code that causes it is (trimmed):
<?php
$itemIds = Array( 79555 );
$index = 'doc';
$adapter = $this->dbAdapter;
$qi = function($name) use ($adapter) {
return $adapter->platform->quoteIdentifier($name);
};
$checkSql = '
SELECT * FROM
'. $qi( $index ) . '
WHERE
id = ' . (int)$itemIds[0];
$checkStatement = $this->dbAdapter->query($checkSql);
$result = $checkStatement->execute();
The exception doesn't seem to occur on any particular trigger, but persists from the time it's first thrown to the time I restart the daemon. I've outputted the sql generated by Zend\DB\Adapter and bar ids being different, there seems to be no diference in the queries from ones that succeed to ones that fail.
There's no associated error in the sphinx logs (that I can see) and if I load neutron/sphinxsearch-api/sphinxapi.php and run GetLastError() it returns a blank string.
My thinking is that it's a connection error - or possibly a misconfiguration with the sphinx config making it timeout, but I'm not sure.
This sounds like you are using persistant connections. At times a connection might be dropped, but your code doesnt account for this, and is still trying to use a connection that has been closed. Maybe try checking for the error, and if get it, reconnects.
In short, make the code resilient to the connection occasionally having been closed.
I have an issue, it has only cropped up now. I am on a shared web hosting plan that has a maximum of 10 concurrent database connections. The web app has dozens of queries, some pdo, some mysql_*.
Loading one page in particular peaks at 5-6 concurrent connections meaning it takes a minimum of 2 users loading it at the same time to spit an error on one or both of them.
I know this is inefficient, I'm sure I can cut that down quite a bit, but that's what my idea is at the moment is to move the pdo code into a function and just pass in a query string and an array of variables, then have it return an array (partly to tidy my code).
THE ACTUAL QUESTION:
How can I get this function to continue to retry until it manages to execute, and hold up the script that called it (and any script that might have called that one) until it manages to execute and return it's data? I don't want things executing out of order, I am happy with code being delayed for a second or so during peak times
Since someone will ask for code, here's what I do at the moment. I have this in a file on it's own so I have a central place to change connection parameters. the if statement is merely to remove the need to continuously change the parameters when I switch from my test server to the liver server
$dbtype = "mysql";
$server_addr = $_SERVER['SERVER_ADDR'];
if ($server_addr == '192.168.1.10') {
$dbhost = "localhost";
} else {
$dbhost = "xxxxx.xxxxx.xxxxx.co.nz";
}
$dbname = "mydatabase";
$dbuser = "user";
$dbpass = "supersecretpassword";
I 'include' that file at the top of a function
include 'db_connection_params.php';
$pdo_conn = new PDO("mysql:host=$dbhost;dbname=$dbname", $dbuser, $dbpass);
then run commands like this all on the one connection
$sql = "select * from tbl_sub_cargo_cap where sub_model_sk = ?";
$capq = $pdo_conn->prepare($sql);
$capq->execute(array($sk_to_load));
while ($caprow = $capq->fetch(PDO::FETCH_ASSOC)) {
//stuff
}
You shouldn't need 5-6 concurrent connections for a single page, each page should only really ever use 1 connection. I'd try to re-architect whatever part of your application is causing multiple connections on a single page.
However, you should be able to catch a PDOException when the connection fails (documentation on connection management), and then retry some number of times.
A quick example,
<?php
$retries = 3;
while ($retries > 0)
{
try
{
$dbh = new PDO("mysql:host=localhost;dbname=blahblah", $user, $pass);
// Do query, etc.
$retries = 0;
}
catch (PDOException $e)
{
// Should probably check $e is a connection error, could be a query error!
echo "Something went wrong, retrying...";
$retries--;
usleep(500); // Wait 0.5s between retries.
}
}
10 concurrent connections is A LOT. It can serve 10-15 online users easily.
Heavy efforts needed to exhaust them.
So there is something wrong with your code.
There are 2 main reasons for it:
slow queries take too much time and thus serving one hit uses one mysql connection for too long.
multiple connections opened from every script.
The former one have to be investigated but for the latter one it's simple:
Do not mix myqsl_ and PDO in one script: you are opening 2 connections at a time.
When using PDO, open connection only once and then use it throughout your code.
Reducing the number of connections in one script is the only way to go.
If you have multiple instances of PDO class in your code, you will need to add that timeout handling code you want to every call. So, heavy code rewriting required anyway.
Replace these new instances with global $pdo; instead. It will take the same amount of time but it will be permanent solution, not temporary patch as you want it.
Please be sensible.
PHP automatically closes all the connections st the end of the script, you don't have to care about closing them manually.
Having only one connection throughout one script is a common practice. It is used by ALL the developers around the world. You can use it without any doubts. Just use it.
If you have transaction and want to log something in database you sometimes need 2 connections in one script
I am writing an Android app which communicates with a PHP backend. The backend db is SQLite 3. The problem is, I am getting this error intermittently PHP Warning: SQLite3::prepare(): Unable to prepare statement: 5, database is locked. I am opening a connection to the database in each PHP file and closing it when the script finishes. I think the problem is that one script locked the database file while writing to it and the second script was trying to access it, which failed. One way of avoiding this would be to share a connection between all of the php scripts. I was wondering if there is any other way of avoiding this?
Edit:
This is the first file:
<?php
$first = SQLite3::escapeString($_GET['first']);
$last = SQLite3::escapeString($_GET['last']);
$user = SQLite3::escapeString($_GET['user']);
$db = new SQLite3("database.db");
$insert = $db->prepare('INSERT INTO users VALUES(NULL,:user,:first,:last, 0 ,datetime())');
$insert->bindParam(':user', $user, SQLITE3_TEXT);
$insert->bindParam(':first', $first, SQLITE3_TEXT);
$insert->bindParam(':last', $last, SQLITE3_TEXT);
$insert->execute();
?>
Here is the second file:
<?php
$user = SQLite3::escapeString($_GET['user']);
$db = new SQLite3("database.db");
$checkquery = $db->prepare('SELECT allowed FROM users WHERE username=:user');
$checkquery->bindParam(':user', $user, SQLITE3_TEXT);
$results = $checkquery->execute();
$row = $results->fetchArray(SQLITE3_ASSOC);
print(json_encode($row['allowed']));
?>
First, when you are done with a resource you should always close it. In theory it will be closed when it is garbage-collected, but you can't depend on PHP doing that right away. I've seen a few databases (and other kinds of libraries for that matter) get locked up because I didn't explicitly release resources.
$db->close();
unset($db);
Second, Sqlite3 gives you a busy timeout. I'm not sure what the default is, but if you're willing to wait a few seconds for the lock to clear when you execute queries, you can say so. The timeout is in milliseconds.
$db->busyTimeout(5000);
I was getting "database locked" all the time until I found out some features of sqlite3 must be set by using SQL special instructions (i.e. using PRAGMA keyword). For instance, what apparently solved my problem with "database locked" was to set journal_mode to 'wal' (it is defaulting to 'delete', as stated here: https://www.sqlite.org/wal.html (see Activating And Configuring WAL Mode)).
So basically what I had to do was creating a connection to the database and setting journal_mode with the SQL statement. Example:
<?php
$db = new SQLite3('/my/sqlite/file.sqlite3');
$db->busyTimeout(5000);
// WAL mode has better control over concurrency.
// Source: https://www.sqlite.org/wal.html
$db->exec('PRAGMA journal_mode = wal;');
?>
Hope that helps.