backup: reduce default kv.bulk_sst.target_size to 16mb

Release note: none.

docs/generated/settings/settings-for-tenants.txt

@@ -29,7 +29,7 @@ kv.allocator.qps_rebalance_threshold	float	0.25	minimum fraction away from the m
 kv.allocator.range_rebalance_threshold	float	0.05	minimum fraction away from the mean a store's range count can be before it is considered overfull or underfull
 kv.bulk_io_write.max_rate	byte size	1.0 TiB	the rate limit (bytes/sec) to use for writes to disk on behalf of bulk io ops
 kv.bulk_sst.max_allowed_overage	byte size	64 MiB	if positive, allowed size in excess of target size for SSTs from export requests; export requests (i.e. BACKUP) may buffer up to the sum of kv.bulk_sst.target_size and kv.bulk_sst.max_allowed_overage in memory
-kv.bulk_sst.target_size	byte size	64 MiB	target size for SSTs emitted from export requests; export requests (i.e. BACKUP) may buffer up to the sum of kv.bulk_sst.target_size and kv.bulk_sst.max_allowed_overage in memory
+kv.bulk_sst.target_size	byte size	16 MiB	target size for SSTs emitted from export requests; export requests (i.e. BACKUP) may buffer up to the sum of kv.bulk_sst.target_size and kv.bulk_sst.max_allowed_overage in memory
 kv.closed_timestamp.follower_reads_enabled	boolean	true	allow (all) replicas to serve consistent historical reads based on closed timestamp information
 kv.protectedts.reconciliation.interval	duration	5m0s	the frequency for reconciling jobs with protected timestamp records
 kv.range_split.by_load_enabled	boolean	true	allow automatic splits of ranges based on where load is concentrated

docs/generated/settings/settings.html

@@ -31,7 +31,7 @@
 <tr><td><code>kv.allocator.range_rebalance_threshold</code></td><td>float</td><td><code>0.05</code></td><td>minimum fraction away from the mean a store's range count can be before it is considered overfull or underfull</td></tr>
 <tr><td><code>kv.bulk_io_write.max_rate</code></td><td>byte size</td><td><code>1.0 TiB</code></td><td>the rate limit (bytes/sec) to use for writes to disk on behalf of bulk io ops</td></tr>
 <tr><td><code>kv.bulk_sst.max_allowed_overage</code></td><td>byte size</td><td><code>64 MiB</code></td><td>if positive, allowed size in excess of target size for SSTs from export requests; export requests (i.e. BACKUP) may buffer up to the sum of kv.bulk_sst.target_size and kv.bulk_sst.max_allowed_overage in memory</td></tr>
-<tr><td><code>kv.bulk_sst.target_size</code></td><td>byte size</td><td><code>64 MiB</code></td><td>target size for SSTs emitted from export requests; export requests (i.e. BACKUP) may buffer up to the sum of kv.bulk_sst.target_size and kv.bulk_sst.max_allowed_overage in memory</td></tr>
+<tr><td><code>kv.bulk_sst.target_size</code></td><td>byte size</td><td><code>16 MiB</code></td><td>target size for SSTs emitted from export requests; export requests (i.e. BACKUP) may buffer up to the sum of kv.bulk_sst.target_size and kv.bulk_sst.max_allowed_overage in memory</td></tr>
 <tr><td><code>kv.closed_timestamp.follower_reads_enabled</code></td><td>boolean</td><td><code>true</code></td><td>allow (all) replicas to serve consistent historical reads based on closed timestamp information</td></tr>
 <tr><td><code>kv.protectedts.reconciliation.interval</code></td><td>duration</td><td><code>5m0s</code></td><td>the frequency for reconciling jobs with protected timestamp records</td></tr>
 <tr><td><code>kv.range_split.by_load_enabled</code></td><td>boolean</td><td><code>true</code></td><td>allow automatic splits of ranges based on where load is concentrated</td></tr>

pkg/ccl/storageccl/export.go

@@ -42,7 +42,7 @@ var ExportRequestTargetFileSize = settings.RegisterByteSizeSetting(
 		"export requests (i.e. BACKUP) may buffer up to the sum of %s and %s in memory",
 		SSTTargetSizeSetting, MaxExportOverageSetting,
 	),
-	64<<20, /* 64 MiB */
+	16<<20,
 ).WithPublic()
 
 // MaxExportOverageSetting is the cluster setting name for the