*: Set the batch delete/insert size by session variable #5413
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We hardcode it to 20k. But if the row size is large. It will still break the transaction size limitation. So we need to provide a way to set it dynamicially.
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/run-all-tests |
zz-jason
reviewed
Dec 15, 2017
sessionctx/variable/tidb_vars.go
Outdated
| @@ -96,6 +96,10 @@ const ( | |||
| // split data into multiple batches and use a single txn for each batch. This will be helpful when deleting large data. | |||
| TiDBBatchDelete = "tidb_batch_delete" | |||
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| // tidb_dml_batch_size is used to split the insret/delete data into small batches. It only takes effort when tidb_batch_insert/tidb_batch_delete is on. | |||
| // Its default value is 20000. When the row size is large. User could change it to a smaller one to avoid break the transaction size limitation. | |||
| TiDBDMLBatchSize = "tidb_dml_batch_size" | |||
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tidb_dml_batch_size may be confused with tidb_max_chunk_size, how about tidb_write_batch_size ?
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tidb_dml_batch_size is used for DML. tidb_max_chunk_size is used for select. DML includes update/insert/delete. So I think tidb_dml_batch_size is a proper name.
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LGTM |
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/run-all-tests |
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/run-all-tests |
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@tiancaiamao @coocood @winkyao PTAL |
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LGTM |
tiancaiamao
approved these changes
Dec 18, 2017
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We hardcode it to 20k. But if the row size is large. It will still break the transaction size limitation. So we need to provide a way to set it dynamically.