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[URGENT] Fix bug when long lines are truncated with extended inserts #477

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merged 1 commit into from
Nov 1, 2025
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[URGENT] Fix bug when long lines are truncated with extended inserts #477

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14 changes: 7 additions & 7 deletions pkg/database/mysql/table.go
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Original file line number Diff line number Diff line change
Expand Up @@ -325,6 +325,13 @@ func (table *baseTable) Stream() <-chan string {
continue
}

// Truncate our insert if it won't fit
if insert.Len() != 0 && insert.Len()+b.Len() > table.data.MaxAllowedPacket-1 {
_, _ = insert.WriteString(";")
valueOut <- insert.String()
insert.Reset()
}
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@bibstha bibstha Oct 28, 2025

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This is how things were in https://github.com/databacker/mysql-backup/pull/473/files#diff-70e106267ef4a71652c95e6eee62fa5d5c435cbb66d47f1afb4474b8fdcb30fd
And logically it makes sense. We should first truncate and then check if "INSERT" should be added or not.

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@deitch deitch Oct 29, 2025

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Just a misplaced section? Ouch.


if insert.Len() == 0 {
_, _ = fmt.Fprint(&insert, strings.Join(
// extra "" at the end so we get an extra whitespace as needed
Expand All @@ -334,13 +341,6 @@ func (table *baseTable) Stream() <-chan string {
_, _ = insert.WriteString(",")
}

// Truncate our insert if it won't fit
if insert.Len() != 0 && insert.Len()+b.Len() > table.data.MaxAllowedPacket-1 {
_, _ = insert.WriteString(";")
valueOut <- insert.String()
insert.Reset()
}

_, _ = b.WriteTo(&insert)
}
if insert.Len() != 0 {
Expand Down