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Option to Set Dynamic Minimum Chunk Size #854

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c69d36d
min chunk
ahirreddy Aug 21, 2024
dbbc4f1
better comments
ahirreddy Aug 22, 2024
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20 changes: 20 additions & 0 deletions bin/pt-online-schema-change
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Original file line number Diff line number Diff line change
Expand Up @@ -10099,6 +10099,12 @@ sub main {
my $avg_rate = 0; # rows/second
my $limit = $o->get('chunk-size-limit'); # brevity
my $chunk_time = $o->get('chunk-time'); # brevity
my $min_chunk_size = $o->get('dynamic-min-chunk-size');
# Exit if the user passes a value less than 1
if ($min_chunk_size < 1) {
_die("The value passed for --dynamic-min-chunk-size is less than 1. Please pass a value greater than or equal to 1.");
}
print ts("Minimum chunk size is $min_chunk_size\n");

my $callbacks = {
init => sub {
Expand Down Expand Up @@ -10312,6 +10318,12 @@ sub main {
$tbl->{nibble_time}, # is this amount of time
);

# Enforce minimum chunk size. If the value is lower than the specified min, update
# the chunk size value accordingly.
if ($tbl->{chunk_size} < $min_chunk_size) {
$tbl->{chunk_size} = $min_chunk_size;
}

if ( $tbl->{chunk_size} < 1 ) {
# This shouldn't happen. WeightedAvgRate::update() may
# return a value < 1, but minimum chunk size is 1.
Expand Down Expand Up @@ -13298,6 +13310,14 @@ them. The existing rows which contain NULL values will be converted to the defau
based on datatype, e.g. 0 for number datatypes, '' for string datatypes.
New rows will use the user defined default value if specified for the column.

=item --dynamic-min-chunk-size

type: int; default: 1

When using dynamic chunk sizing, do not copy chunks smaller than this desired minimum chunk size.

The minimum value for this option is 1 and default value is 1.

=item --only-same-schema-fks

Check foreigns keys only on tables on the same schema than the original table.
Expand Down