[Checkins] SVN: relstorage/trunk/notes/migrate-to-1.5.txt Provide an additional script to clean out the old bytea data for the deleted column.
Martijn Pieters
mj at zopatista.com
Wed Jun 15 14:08:01 EDT 2011
Log message for revision 121955:
Provide an additional script to clean out the old bytea data for the deleted column.
Changed:
U relstorage/trunk/notes/migrate-to-1.5.txt
-=-
Modified: relstorage/trunk/notes/migrate-to-1.5.txt
===================================================================
--- relstorage/trunk/notes/migrate-to-1.5.txt 2011-06-15 17:47:59 UTC (rev 121954)
+++ relstorage/trunk/notes/migrate-to-1.5.txt 2011-06-15 18:08:01 UTC (rev 121955)
@@ -36,6 +36,19 @@
DROP COLUMN oldbytea;
COMMIT;
+Note that DROP COLUMN does not reclaim the space occupied by the oldbytea
+column. If there is a large amount of data in the blob_chunk table, you may
+want to re-initialize the whole table by moving the data to a temporary table
+and then copying it back:
+
+ BEGIN;
+ CREATE TEMP TABLE blob_chunk_copy (LIKE blob_chunk) ON COMMIT DROP;
+ INSERT INTO blob_chunk_copy SELECT * FROM blob_chunk;
+ TRUNCATE blob_chunk;
+ INSERT INTO blob_chunk SELECT * FROM blob_chunk_copy;
+ COMMIT;
+
+
MySQL history-preserving
------------------------
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