<p><codeph>MEMORY_SPILL_RATIO</codeph> identifies the memory usage threshold for memory-intensive operators in a transaction. When the transaction reaches this memory threshold, it spills to disk. Greenplum Database uses the <codeph>MEMORY_SPILL_RATIO</codeph> to determine the initial memory to allocate to a transaction.</p>
<p> The minimum <codeph>MEMORY_SPILL_RATIO</codeph> percentage you can specify for a resource group is 1. The maximum is 100. The upper limit of this ratio is (100 - <codeph>MEMORY_SHARED_QUOTA</codeph>). The default <codeph>MEMORY_SPILL_RATIO</codeph> is 20.</p>
<p>The sum of <codeph>MEMORY_SHARED_QUOTA</codeph> and <codeph>MEMORY_SPILL_RATIO</codeph> must not exceed 100.</p>
<p> The minimum <codeph>MEMORY_SPILL_RATIO</codeph> percentage you can specify for a resource group is 0. The maximum is 100. The default <codeph>MEMORY_SPILL_RATIO</codeph> is 20.</p>
<p>You define the <codeph>MEMORY_SPILL_RATIO</codeph> when you create a resource group. You can selectively set this limit on a per-query basis at the session level with the <codeph><xrefhref="../ref_guide/config_params/guc-list.xml#memory_spill_ratio"type="section"/></codeph> server configuration parameter.</p>
<pd>The quota of shared memory in the resource group. Resource groups with a <codeph>MEMORY_SHARED_QUOTA</codeph> threshold set aside a percentage of memory allotted to the resource group to share across transactions. This shared memory is allocated on a first-come, first-served basis as available. A transaction may use none, some, or all of this memory. The minimum memory shared quota percentage you can specify for a resource group is 0. The maximum is 100. The default <codeph>MEMORY_SHARED_QUOTA</codeph> value is 20. The sum of the <codeph>MEMORY_SHARED_QUOTA</codeph> and <codeph>MEMORY_SPILL_RATIO</codeph> values specified for a resource group cannot exceed 100.</pd>
<pd>The quota of shared memory in the resource group. Resource groups with a <codeph>MEMORY_SHARED_QUOTA</codeph> threshold set aside a percentage of memory allotted to the resource group to share across transactions. This shared memory is allocated on a first-come, first-served basis as available. A transaction may use none, some, or all of this memory. The minimum memory shared quota percentage you can specify for a resource group is 0. The maximum is 100. The default <codeph>MEMORY_SHARED_QUOTA</codeph> value is 20.</pd>
<pd>The memory usage threshold for memory-intensive operators in a transaction. When the transaction reaches this threshold, it spills to disk. The minimum memory spill ratio percentage you can specify for a resource group is 1. The maximum is 100. The upper limit is (100 - <codeph>MEMORY_SHARED_QUOTA</codeph>). The default <codeph>MEMORY_SPILL_RATIO</codeph> value is 20. The sum of the <codeph>MEMORY_SHARED_QUOTA</codeph> and <codeph>MEMORY_SPILL_RATIO</codeph> values specified for a resource group cannot exceed 100.</pd>
<pd>The memory usage threshold for memory-intensive operators in a transaction. When the transaction reaches this threshold, it spills to disk. The minimum memory spill ratio percentage you can specify for a resource group is 0. The maximum is 100. The default <codeph>MEMORY_SPILL_RATIO</codeph> value is 20.</pd>