Count rows queries #1442
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Count rows queries #1442
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online schema changes with deletion. architecture as detailed explained here: https://kb.wixpress.com/x/8pocBQ Where clause condition will always receive the default 1=1. in case we would like to delete table data we will use the where clause as in a "select" meaning we will put the data we want to save in the where clause. to include values on the where clause - use the condition as it is. for exclude values please put "not" before. Please note : Where clause condition will be enforced only from the source table and not from the binlog. meaning if I put a where clause of id < 100, and id # 2 was updated \ inserted, it will be in the new table because this DML will be taken from the binlog. this is a feature since this is newly update\insert otherwise it should be inserted into the binlogs as a deleted row. If you are using one filter operation with in , please don't put more than 5 values. otherwise please use the sub-select option. For hash \ string it is better to use the sub-select option, avoiding string manipulation issues in the middle (Jenkins, ansible, Casper). Where clause can not be edited in the middle of ghost run.
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| query := fmt.Sprintf(`select /* gh-ost */ count(*) as count_rows from %s.%s`, sql.EscapeName(this.migrationContext.DatabaseName), sql.EscapeName(this.migrationContext.OriginalTableName)) | ||
| query := fmt.Sprintf(`select /* gh-ost */ table_rows as count_rows from information_schema.tables where table_schema="%s" and table_name="%s"`, sql.EscapeName(this.migrationContext.DatabaseName), sql.EscapeName(this.migrationContext.OriginalTableName)) |
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table_rows from information_schema is an estimate, not necessarily the exact row count. Elsewhere we estimate the row count if select count(*) cannot complete. So we do not wish to change this.
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This PR [briefly explain what it does]
script/cibuildreturns with no formatting errors, build errors or unit test errors.