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Getting the data out of a memo field |
Sun, Jan 31 2010 8:21 AM | Permanent Link |
Roy Lambert NLH Associates Team Elevate | I'm dumping the contents of a CLOB into a stringlist for further processing. Speed is fine whilst the CLOB is "reasonably" sized (say < 1Mb) but as size climbs it gets a lot worse. To give some idea
Chars Lines ms 204352 2850 46 324210 4464 78 452218 6204 141 542929 7462 203 699108 9809 171 819093 11145 218 884900 12061 250 1188894 16092 312 1309774 17814 327 2738211 37204 1107 3848943 52532 2013 4136634 55929 2294 5696786 77038 4166 15638443 211371 31497 I'm using the default settings for BLOB block size. There are 4 CLOB columns and 1 BLOB column and if I increase the BLOB block size I'm going to have a shed load of wasted space. The table involved is my email table and this particular column is the email in encoded format. All I want out of is the headers (say max first 3k chars). Is there a fast way of getting those? Roy Lambert ps don't even suggest Copy - been there, done that, its just as slow. |
Mon, Feb 1 2010 11:16 AM | Permanent Link |
Tim Young [Elevate Software] Elevate Software, Inc. timyoung@elevatesoft.com | Roy,
<< I'm using the default settings for BLOB block size. There are 4 CLOB columns and 1 BLOB column and if I increase the BLOB block size I'm going to have a shed load of wasted space. The table involved is my email table and this particular column is the email in encoded format. All I want out of is the headers (say max first 3k chars). Is there a fast way of getting those? >> Due to the random-access nature of BLOB streams in Delphi, we have to read the entire BLOB in order to avoid transactional issues. What we do here in our outgoing mail server table is store the headers separately from the body, and it seems to work pretty well. << ps don't even suggest Copy - been there, done that, its just as slow. >> What do you mean by "copy" ? -- Tim Young Elevate Software www.elevatesoft.com |
Tue, Feb 2 2010 4:50 AM | Permanent Link |
Roy Lambert NLH Associates Team Elevate | Tim
>Due to the random-access nature of BLOB streams in Delphi, we have to read >the entire BLOB in order to avoid transactional issues. What we do here in >our outgoing mail server table is store the headers separately from the >body, and it seems to work pretty well. That's what I did in my old app but I changed in the new one to holding the complete encoded email. I used to split headers, message and attachments but felt it was better to keep them together. I may have to revise the decision ><< ps don't even suggest Copy - been there, done that, its just as slow. >> > >What do you mean by "copy" ? Copy(TableField,AsString,1,3000) I added that just in case some kindly soul suggested it as an approach. Roy Lambert |
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