AMQ-9541 limit expensive queries on the database side #1275
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| PreparedStatement s = null; | ||
| ResultSet rs = null; | ||
| try { | ||
| s = c.getConnection().prepareStatement(this.statements.getFindDurableSubMessagesByPriorityStatement()); | ||
| s = c.getConnection().prepareStatement(this.limitQuery(this.statements.getFindDurableSubMessagesByPriorityStatement())); | ||
| s.setMaxRows(Math.min(maxReturned * 2, maxRows)); |
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I'm not sure why there is "* 2" for the setMaxRows
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Not an expert, but I did some git blame digging, the * 2 got introduced in https://issues.apache.org/jira/browse/AMQ-2980, to take into account the messages from low and high priority queues, to ensure that none get lost and to not hog more memory than needed. Down the road this happened java.sql.SQLException: setMaxRows() out of range. 50871918 > 50000000. (https://issues.apache.org/jira/browse/AMQ-1870). The solution to this was to pick the lowest of two values (maxReturner * 2) and maxRows, to ensure such exception does not happen.
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| PreparedStatement s = null; | ||
| ResultSet rs = null; | ||
| try { | ||
| s = c.getConnection().prepareStatement(this.statements.getFindDurableSubMessagesStatement()); | ||
| s = c.getConnection().prepareStatement(this.limitQuery(this.statements.getFindDurableSubMessagesStatement())); | ||
| s.setMaxRows(Math.min(maxReturned * 2, maxRows)); |
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I'm not sure why there is "* 2" for the setMaxRows
…ere there is a setMaxRows on the statement.
jeanouii
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…ere there is a setMaxRows on the statement.