Static query optimization

Abstract

Techniques and structures for tuning database queries. Actual statistics associated with data stored are retrieved from at least one memory device. The data is associated with one or more tenants of the multi-tenant database system. The actual statistics include at least one type of statistic maintained for the data. A subset of the actual statistics is selected based on a data trait targeted for optimization. A statistical value is calculated for each actual statistic from the subset of actual statistics across one or more tenants having the data trait targeted for optimization. An optimal query plan is determined based on the original query and the calculated statistical values.

1 - 20 . (canceled) 
     
     
         21 . A method comprising:
 retrieving actual statistics associated with data stored on at least one memory device having data associated with multiple tenants of multi-tenant database environment and the tenants have one or more data traits targeted for query optimization, wherein the actual statistics comprise actual statistical values associated with the one or more tenants;   selecting a subset of the actual statistics;   computing, with a query tuning and processing device, synthetic statistics for the one or more tenants based on the actual statistical values and the data traits for the tenants based on a predetermined value associated with the subset of the actual statistics and the predetermined value corresponds to an exemplary value based on a historical association of the one or more data traits with a selected tenant of the one or more tenants; and   determining, by the query tuning and processing device, one or more query plans for optimally processing queries on behalf of the one or more tenants based for which the synthetic statics have been computed utilizing the synthetic statistics.   
     
     
         22 . The method of  claim 21  wherein the synthetic statistics are further based on an average value associated with the subset of the actual statistics. 
     
     
         23 . The method of  claim 22  wherein the average value comprises a predetermined value representing an exemplary value based on a data trait of an exemplary tenant of the one or more tenants. 
     
     
         24 . The method of  claim 23  wherein the exemplary value is computed based on multiple values comprising a highest value associated with the exemplary tenant having the data trait targeted for optimization. 
     
     
         25 . The method of  claim 24  wherein the multiple values further comprise a lowest value associated with the exemplary tenant having the data trait targeted for optimization. 
     
     
         26 . A non-transitory computer-readable medium having stored thereon instructions that, when executed by one or more processors coupled with a memory device, are configurable to cause the one or more processors to tune queries in a multi-tenant database environment, the one or more processors to:
 retrieve actual statistics associated with data stored on at least one memory device having data associated with multiple tenants of multi-tenant database environment and the tenants have one or more data traits targeted for query optimization, wherein the actual statistics comprise actual statistical values associated with the one or more tenants;   select a subset of the actual statistics;   compute, with a query tuning and processing device, synthetic statistics for the one or more tenants based on the actual statistical values and the data traits for the tenants based on a predetermined value associated with the subset of the actual statistics and the predetermined value corresponds to an exemplary value based on a historical association of the one or more data traits with a selected tenant of the one or more tenants; and   determine, by the query tuning and processing device, one or more query plans for optimally processing queries on behalf of the one or more tenants based for which the synthetic statics have been computed utilizing the synthetic statistics.   
     
     
         27 . The non-transitory computer-readable medium of  claim 26  wherein the synthetic statistics are further based on an average value associated with the subset of the actual statistics. 
     
     
         28 . The non-transitory computer-readable medium of  claim 27  wherein the average value comprises a predetermined value representing an exemplary value based on a data trait of an exemplary tenant of the one or more tenants. 
     
     
         29 . The non-transitory computer-readable medium of  claim 28  wherein the exemplary value is computed based on multiple values comprising a highest value associated with the exemplary tenant having the data trait targeted for optimization. 
     
     
         30 . The non-transitory computer-readable medium of  claim 29  wherein the multiple values further comprise a lowest value associated with the exemplary tenant having the data trait targeted for optimization. 
     
     
         31 . A system comprising:
 a memory device;   one or more hardware processors coupled with the memory device, the one or more hardware processors configurable to retrieve actual statistics associated with data stored on at least one memory device having data associated with multiple tenants of multi-tenant database environment and the tenants have one or more data traits targeted for query optimization, wherein the actual statistics comprise actual statistical values associated with the one or more tenants, to select a subset of the actual statistics, to compute, with a query tuning and processing device, synthetic statistics for the one or more tenants based on the actual statistical values and the data traits for the tenants based on a predetermined value associated with the subset of the actual statistics and the predetermined value corresponds to an exemplary value based on a historical association of the one or more data traits with a selected tenant of the one or more tenants, and to determine, by the query tuning and processing device, one or more query plans for optimally processing queries on behalf of the one or more tenants based for which the synthetic statics have been computed utilizing the synthetic statistics.   
     
     
         32 . The system of  claim 31  wherein the synthetic statistics are further based on an average value associated with the subset of the actual statistics. 
     
     
         33 . The system of  claim 32  wherein the average value comprises a predetermined value representing an exemplary value based on a data trait of an exemplary tenant of the one or more tenants. 
     
     
         34 . The system of  claim 33  wherein the exemplary value is computed based on multiple values comprising a highest value associated with the exemplary tenant having the data trait targeted for optimization. 
     
     
         35 . The system of  claim 34  wherein the multiple values further comprise a lowest value associated with the exemplary tenant having the data trait targeted for optimization.