[Mapserver-dev] Re: mapsde.c

[Paul Ramsey]

Ah, the scales lift from my eyes :)  The implications of versioned 
versus non-versioned. For the record, the SDE we are going against is 
not versioned, and your fix seems like a very reasonable way to 
crosscut the two cases.

On 18-Oct-04, at 5:34 PM, Howard Butler wrote:

> This afternoon Brock and I implemented a couple of small changes to 
> prevent this from happening.  The behavior we defined is that if the 
> user did not set a version, no version queries are done (instead of 
> defaulting to SDE.DEFAULT).  We still need to have the ability to set 
> the version to SDE.DEFAULT, however.
>
> At 07:03 PM 10/18/2004, Paul Ramsey wrote:
>> I have a suspicion that some of the version handling code might be 
>> making us slower than we need to be.
>>
>> In particular, here we check for a version, and use SDE.DEFAULT if 
>> there is not one provided, then we go and do SE_version_get_info() 
>> which will later provide us with a state_id. But, if our version is 
>> SDE.DEFAULT, isn't our state_id == SE_DEFAULT_STATE_ID. So we don't 
>> need to do the version_get_info(), and we also do not need to do the 
>> tests for SE_stateinfo_is_open(), or the SE_stream_set_state() and 
>> all the stuff preceding it.
>>
>> These are questions, not statements, I could be completely wrong in 
>> my interpretation.
>>
>>   if (numparams < 3){
>>     // User didn't specify a version, we'll use SDE.DEFAULT
>>     if (layer->debug)
>>       msDebug("msSDELayerOpen(): Layer %s did not have a"
>>               "specified version.  Using SDE.DEFAULT.\n", 
>> layer->name);
>>       status = SE_version_get_info(sde->connection, "SDE.DEFAULT", 
>> version);
>>   }
>>   else {
>>     if (layer->debug)
>>       msDebug("msSDELayerOpen(): Layer %s specified version %s.\n",
>>               layer->name,
>>               params[2]);
>>     status = SE_version_get_info(sde->connection, params[2], version);
>>   }
>>
>> Paul
>>
>> Brock Anderson wrote:
>>
>>> Now that FastCGI and the SDE connection pooling code seem to work,
>>> I've had a chance to do some performance tests on the new and
>>> improved MapServer. Some early results show that Mapserver is about
>>> 1-2 seconds faster per getMap request than it was with regular CGI,
>>> but it is still much slower than ArcIMS for simple getMap requests. I
>>> was testing with a map that had three fairly simple layers; ArcIMS
>>> returns in ~800ms, MapServer in about 1600ms.
>>> It looks like msSDELayerOpen() and msSDELayerClose() account for much
>>> of that difference. I added some debugging statements to the code,
>>> which revealed:
>>> In msSDELayerOpen():
>>> SE_version_get_info() takes 20 - 30ms
>>> SE_layer_get_info() takes ~100ms
>>> SE_stream_set_state() takes ~10ms
>>> the code inside the block:
>>>   if (!(sde->state_id == SE_DEFAULT_STATE_ID)){
>>>    ...
>>>   }
>>> takes 20 - 100ms
>>> In msSDELayerClose()
>>> SE_stream_free() takes 20 - 30ms
>>> These may seem like minor performance hits, but they occur for each 
>>> layer, and those numbers become quite significant.  I especially
>>> worry about the way we handle state ids, and I wonder if we are doing
>>> it efficiently.  Frank and Howard: do either of you have ideas for
>>> how mapsde.c could be streamlined?
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>
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