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![Erik Johnston](/assets/img/avatar_default.png)
Due to the table locks taken out by the naive upsert, the table statistics may be out of date. During deduplication it is important that the correct index is used as otherwise a full table scan may be incorrectly used, which can end up thrashing the database badly.
31 lines
1.3 KiB
SQL
31 lines
1.3 KiB
SQL
/* Copyright 2018 New Vector Ltd
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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-- analyze user_ips, to help ensure the correct indices are used
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INSERT INTO background_updates (update_name, progress_json) VALUES
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('user_ips_analyze', '{}');
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-- delete duplicates
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INSERT INTO background_updates (update_name, progress_json, depends_on) VALUES
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('user_ips_remove_dupes', '{}', 'user_ips_analyze');
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-- add a new unique index to user_ips table
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INSERT INTO background_updates (update_name, progress_json, depends_on) VALUES
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('user_ips_device_unique_index', '{}', 'user_ips_remove_dupes');
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-- drop the old original index
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INSERT INTO background_updates (update_name, progress_json, depends_on) VALUES
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('user_ips_drop_nonunique_index', '{}', 'user_ips_device_unique_index');
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